THMMY.gr

ComSoc Asia Pacfic Region invites you to attend a Webinar on 5G Wireless Cellular Networks, by IEEE Fellow, Professor Branka Vucetic from University of Sydney. This talk will address the drivers, visions and requirements for the fifth generation (5G) of wireless cellular communication networks, in particular, the new 5G technologies and research directions, including significant capacity improvements. The Webinar will be held on Tuesday October 29, 2013 only! Don't miss it!

Topic: 5G Wireless Cellular Networks
Date: Tuesday, October 29, 2013 Time: 16:00-17:00pm (Beijing Time), China Time (Beijing, GMT+08:00)
Speaker: Prof Branka Vucetic, University of Sydney

About the Speaker
Prof. Branka Vucetic currently works as Peter Nicol Russel Chair and Director of the Centre of Excellence in Telecommunications at the University of Sydney. During her career she has held various research and academic positions in Yugoslavia, Australia and UK. Her research interests include wireless communications, coding, digital communication theory and MIMO systems. She co-authored four books and more than three hundred papers in telecommunications journals and conference proceedings. She has been elected to the grade of IEEE Fellow for contributions to the theory and applications of channel coding.

How to Attend

Topic: 5G Wireless Cellular Networks
Date: Tuesday, October 29, 2013
Time: 4:00 pm, China Time (Beijing, GMT+08:00)
Meeting Number: 591 941 226
Meeting Password: wireless

https://ieeemeetings.webex.com/mw0307l/mywebex/default.do?service=1&siteurl=ieeemeetings&nomenu=true&main_url=%2Fmc0806l%2Fe.do%3Fsiteurl%3Dieeemeetings%26AT%3DMI%26EventID%3D252285252%26UID%3D1735463637%26Host%3D41c1495c5a02243d3a%26FrameSet%3D2%26PW%3DNYzM2MmJlYzBk

Αρκετά ενδιαφέρον webinar και πολύ σχετικό με το μάθημα  ;). Αξίζει να το παρακολουθήσετε!!!!

Στο πρώτο μάθημα των Κινητών και Δορυφορικών επικοινωνιών ασχοληθήκαμε με τα Κυψελωτά Δίκτυα, τη δομή τους και είδαμε πως εξαρτάται η επιλογή του μεγέθους της συστάδας από τις ομοκαναλικές παρεμβολές ή με άλλα λόγια του QoS. Αναφερθήκαμε στο LTE και το LTE-Advance και είδαμε την τάση που υπάρχει να πάμε σε δομές υψηλού N κ.α.

Αλλά είναι όλα αυτά σύγχρονα; Αξίζει να αφιερώσω χρόνο για να τα δω σε βάθος; Συμβαίνουν στην πραγματικότητα; κ.α.

Για να καταφέρετε να απαντήσουμε σε όλα αυτά αξίζει να παρακολουθούμε προς τα που κινείται ο έξω-από-τη-σχολή κόσμος, μέσα από webinar, seminars, conferences, tutorials κ.α.

Με βάση το παραπάνω σκεπτικό θα σας ανεβάζω εδώ (ή αν δε θέλετε να γίνεται χαμός μπορούμε να ζητήσουμε από κάποιον moderator να σπάσει ή να αλλάξει όνομα στο topic) διάφορες ενδιαφέρουσες πληροφορίες και εκδηλώσεις που μπορείτε να παρακολουθήσετε μέσω internet ή πιθανότατα να έχετε την ευκαιρία να δείτε από κοντά και μπορούν να δράσουν συμπληρωματικά με το μάθημα.

Το σημερινό, λοιπόν, θέμα είναι σχετικό με το πρώτο μας μάθημα και έχει τίτλο: Small Cell Wireless Networks (tutorial). Το συγκεκριμένο tutorial έχει διάρκεια 2hr 24min 3sec, είναι video.

Η περιγραφή του είναι:

Small cell networks have recently emerged as a key cost-effective solution for enhancing the capacity, coverage, and performance of wireless cellular systems. This tutorial, provides a comprehensive overview on Small Cell Networks(SCNs) while highlighting key challenges and associated solutions, beginning with an overview on advanced analytical techniques, such as stochastic geometry, suitable for modeling and analyzing SCNs.

Details of advanced interference management techniques tailored for the unique features of SCNs are examined, introducing key concepts such as cell range expansion, cell selection and adaptive resource partitioning that lie at the heart of next-generation LTE-Advanced systems. Self-organizing networks (SONs) as applied to small cell deployment is covered.  This tutorial concludes with an in-depth overview on the current and future challenges facing the large-scale deployment of wireless SCNs.

Το link για εγγραφή και παρακολούθηση είναι: https://www.comsoc.org/form/tutorial-registration-small-cell-wireless-networks (https://www.comsoc.org/form/tutorial-registration-small-cell-wireless-networks). 


Κάποιες επιπλέον παρατηρήσεις, τις οποίες πρέπει να έχετε στο μυαλό σας:
- Δεν υπάρχουν μόνο οι ομοκαναλικές παρεμβολές. Υπάρχουν σαν κατηγορίες και οι inter-carrier & adjacent channel interference
- Η μελέτη και έρευνα για την καταπολέμηση ή εκμετάλλευση των interference είναι σε εξέλιξη.

Και μία ανακοίνωση για το μάθημα:

Για αυτή τη βδομάδα θα κάνουμε ασκήσεις την Δευτέρα 21/10/2013, ενώ την Τρίτη θα γίνει θεωρία με τον κ. Καραγιαννίδη.

Στο eThmmy, στο υλικό του μαθήματος, μπορείτε να βρείτε την παρουσίαση του μαθήματος των ασκήσεων στα Κυψελωτά Συστήματα.

Σημείωση:

Το τελευταίο παράδειγμα έχει κάποια μοντέλα  που θα δούμε στο επόμενο μάθημα ασκήσεων. Συνεπώς, αν κάποιος διαβάσει τις παρουσιάσεις, ας το παραλείψει σε πρώτη φάση.

Αν ενδιαφέρεστε να δείτε κάποια περισσότερα πράγματα πάνω σε OFDM, όπως:
 - τι είναι
- ποια η ιστορία του
- η δομή του
- τι πλεονεκτήματα και τι μειονεκτήματα έχει
- που χρησιμοποιείται
- που θεωρείτε ότι θα παίξει σημαντικό ρόλο,

μπορείτε να ρίξετε μία ματιά στο Βιβλίο: MIMO-OFDM for LTE, WiFi and WiMAX: Coherent versus Non-coherent and Cooperative Turbo Transceivers (http://course.sdu.edu.cn/G2S/eWebEditor/uploadfile/20130121153751721.pdf)

Σχετικά με το βιβλίο:

MIMO-OFDM for LTE, WIFI and WIMAX: Coherent versus Non-Coherent and Cooperative Turbo-Transceivers provides an up-to-date portrayal of wireless transmission based on OFDM techniques augmented with Space-Time Block Codes (STBCs) and Spatial-Division Multiple Access (SDMA). The volume also offers an in-depth treatment of cutting-edge Cooperative Communications.
This monograph collates the latest techniques in a number of specific design areas of turbo-detected MIMO-OFDM wireless systems. As a result a wide range of topical subjects are examined, including channel coding and multiuser detection (MUD), with a special emphasis on optimum maximum-likelihood (ML) MUDs, reduced-complexity genetic algorithm aided near-ML MUDs and sphere detection. The benefits of spreading codes as well as joint iterative channel and data estimation are only a few of the radical new features of the book.

Also considered are the benefits of turbo and LDPC channel coding, the entire suite of known joint coding and modulation schemes, space-time coding as well as SDM/SDMA MIMOs within the context of various application examples. The book systematically converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems; the depth of discussions increases towards the end of the book.
- Discusses many state-of-the-art topics important to today's wireless communications engineers.
- Includes numerous complete system design examples for the industrial practitioner.
- Offers a detailed portrayal of sphere detection.
- Based on over twenty years of research into OFDM in the context of various applications, subsequently presenting comprehensive bibliographies.




Να σημειώσω στο σημείο αυτό ότι δεν θα χρειαστείτε το βιβλίο αυτό για να κάνετε τις εργασίες (ή έστω όλο αυτό το βιβλίο), αλλά είναι ένας πολύ καλός οδηγός για το OFDM.

Στο υλικό μαθήματος έχουν ανέβει τα εξής βιβλία:

- Κινητή Ραδιοεπικοινωνία (Φ.-Ν. Παυλίδου)
- Wireless Communications: Principles and Practice (Rappaport - Prentice Hall 1st Ed 1996)
- Satellite Communications Systems (Maral & Bousquet - John Wiley & Sons 5th Ed 2009)

Στο ethmmy στην ενότητα Εργασίες-Εργαστήρια του μαθήματος, μπορείτε να δηλώσετε τις ομάδες σας για την εργασία στο OFDM. Οι δηλώσεις λήγουν την Δευτέρα 04/11/2013.

Υπενθύμιση για την εργασία!

Εγώ έφτιαξα μια ομάδα ανοιχτή (Νο.1) αλλά να ξέρετε δεν μπορώ να υποσχεθώ οτι θα κάνω την εργασία μέχρι τέλους...θα προσπαθήσω αλλά θα εξαρτηθεί απο τον χρόνο μου και απο το πως θα πάει...

Το λέω επειδή κάποιος μπήκε ήδη μαζί μου και δεν είμαι σίγουρος για το ποιος είναι..

οπότε όποιον δεν τον πειράζει ας μπεί στην ίδια ομάδα με μένα

Οι ομάδες για την εργασία είναι των 2 ή των 3 ατόμων;

2 ή 3. Το ανοίγω τώρα για 3 για να μπορείτε να δηλώσετε.

Υπάρχει θέμα με την δήλωση των ομάδων...δε μας δίνει επιλογή να φτιάξουμε ομάδες όπως θέλουμε αλλά μας βάζει αυτόματα στην πρώτη ομάδα που έχει άδεια θέση

Νομίζω ότι το έφτιαξα. Για κάνε μία δοκιμή.

κομπλε

Στο eThmmy θα βρείτε την παρουσίαση για τις Απώλειες και τις διαλείψεις μεγάλης κλίμακας που έγινε στο μάθημα των ασκήσεων.

Σήμερα λήγει η προθεσμία για την δήλωση ενδιαφέροντος για εργασία.

Αν υπάρχει κάποιος που θέλει να κάνει εργασία και δεν το έχει δηλώσει ακόμη, ας βιαστεί. Οι δηλώσεις γίνονται στην αντίστοιχη καρτέρα (Εργασίες-Εργαστήρια) στο eThmmy. 

Στη σελίδα http://www.comsoc.org/webinars θα βρείτε το webinar που οργανώνει το IEEE Communications Society με θέμα "Mobile Backhaul for small cells".

MODERATOR:

Glenn Parsons, IEEE Communications Magazine Technical Editor,
IEEE 802.1 Vice Chair, Ericsson Standards Advisor

PRESENTERS:

Stefano Ruffini, R&D Expert, Ericsson, ITU-T Associate
Tim Pearson, Technology Strategist, Sprint, Principle MEF Representative

Για όποιον ενδιαφέρεται να δει μία προσέγγιση του Ασύρματου καναλιού (fading) από μία πλευρά πιο Information Theory, καθώς και άλλα ζητήματα που αφορούν τις Ασύρματες Τηλεπικοινωνίες. Μπορεί να ρίξει μία ματιά στο βιβλίο των Che και Viswanath "Fundamentals of Wireless Communication" στο http://www.eecs.berkeley.edu/~dtse/book.html.

Εξελίξεις στις τηλεπικοινωνίες:

Duke University Students Discover a Way to Charge Cell Phones With Wi-Fi


Για περισσότερα δείτε παρακάτω:
http://inhabitat.com/duke-university-students-find-a-way-to-charge-cell-phones-with-wi-fi/

Στο eThmmy έχουν ανέβει:
1. Οι παρουσιάσεις των διαλέξεων θεωρίας του κ. Καραγιαννίδη,
2. Η παρουσίαση σε κανάλια διαλείψεων μικρής κλίμακας του μαθήματος των ασκήσεων.

Ένα ενδιαφέρον άρθρο: New Indoor Navigation Technologies Work Where GPS Can’t

http://spectrum.ieee.org/telecom/wireless/new-indoor-navigation-technologies-work-where-gps-cant

Ενημέρωση για ευκαιρίας εργασίας τελειοφοίτων και αποφοίτων στην ESA  :D

Στην πρώτη ώρα του αυριανού μαθήματος (Τρίτη 26/11/2013 - 13.00-15.00) θα γίνει ενημέρωση για ευκαιρίες εργασίας στον Ευρωπαϊκό Οργανισμός Διαστήματος (European Space Agent - http://www.esa.int/) που αφορούν τελειόφοιτους και απόφοιτους του τμήματος.


Η δήλωση ενδιαφέροντος για τις συγκεκριμένες θέσεις έχει καταληκτική ημερομηνία: 15/12/2013.

Στο Υλικό Μαθήματος στο eThmmy έχει ανέβει η παρουσίαση του μαθήματος ασκήσεων που αφορά τους Δέκτες διαφορικής λήψης.

utr!

Webinar: "LTE and LTE-A MIMO Link Adaption Performance Optimization"

LTE/LTE-Advanced utilizes a 100% packet-switched air interface to provide numerous services to connected user equipment (UE).   To maximize throughput to each UE communicating over a complex time-varying channel, LTE/LTE-A adds MIMO link adaptation to the adaptive coding and modulation methods used in UMTS.  This presentation will cover the link adaptation methods in LTE/LTE-A and present strategies for simulating and designing receivers to implement these methods.


Link: http://www.comsoc.org/webinars

Τηλεπικοινωνιακά νέα  ;)

IEEE 1901.2™ “Standard Approved - Driven and Sponsored by IEEE ComSoc Power-Line Communications Standards Committee

According to the latest news from IEEE Standards Association, IEEE has approved The IEEE 1901.2™ “Standard for Low-Frequency (less than 500kHz) Narrowband Power-Line Communications for Smart-Grid Applications.” The achievement has been driven and is sponsored by the Power-Line Communications Standards Committee of the IEEE Communications Society (IEEE ComSoc).

“The IEEE 1901.2 standard raises the bar of performance with mandatory differential and robust coherent modulation, with added enhancements for increased data rates greater than 300kbps,” said Jim LeClare, chair of the IEEE Low-Frequency Narrowband Power-Line Communications Working Group. “The design potential for low-frequency, narrowband OFDM (Orthogonal Frequency Division Multiplexing) Power-Line Communications (PLC) has expanded past the energy industry, with designs spanning the globe in industrial automation, transportation, street lighting, mining, medical applications and more.”

In August 2013, IEEE 1901.2 completed its first sponsor ballot, which paved the way for its approval. Because the standard was natively designed for the modern smart grid, it leverages techniques and recent innovations in communications technology and the smart grid security framework. Comprised of three foundational components—physical/medium access (PHY/MAC) layer, coexistence and electromagnetic-compatibility (EMC) requirements—IEEE 1901.2 supports the balanced and efficient use of the PLC channel by all classes of low-frequency and narrowband devices. The standard defines detailed mechanisms for coexistence among standard technologies operating in the same frequency band.

“Over a two- to three-year time frame, the IEEE 1901.2 working group has worked very hard to bring this standard from draft form to full approval,” said Oleg Logvinov, vice chair of IEEE Low-Frequency Narrowband Power-Line Communications Working Group and director of special assignments, Industrial and Power Conversion Division, STMicroelectronics. “I would like to extend a hearty congratulations to the entire working group for reaching this milestone. Having this standard widely available is paramount to the forward progress of technologies provided by semiconductor manufacturers, meter and systems manufacturers, software developers, service providers, utilities and more.”

Designed to specify secure PLC at data rates up to 500kbps and at transmission frequencies of less than 500kHz for applications, IEEE 1901.2 addresses low-frequency, narrowband PLC over low-voltage lines of less than 1000V between transformer and meter, through transformer low-voltage to medium-voltage (1000V up to 72kV) and through transformer medium-voltage to low-voltage power lines in both urban and in long-distance (multi-kilometer) rural communications.

For more information about the IEEE Low-Frequency Narrowband Power-Line Communications Working Group, please visit the working group’s Web site.

IEEE 1901.2 is scheduled to be published on 6 December 2013 and will be available for purchase at the IEEE Standards Store.


Πηγή: http://www.comsoc.org/blog/ieee-19012%E2%84%A2-%E2%80%9Cstandard-approved-driven-and-sponsored-ieee-comsoc-power-line-communications-stand

Στα πλαίσια του μαθήματος θα πραγματοποιηθούν δύο εργαστήρια, ένα πάνω σε διαλείψεις μικρής και μεγάλης κλίμακας (small and large scale fading) και ένα πάνω σε OFDM SISO συστήματα.
Πιο συγκεκριμένα, στο πρώτο εργαστήριο θα δούμε τα παρακάτω μοντέλα:
- Μοντέλο δύο-ακτίνων - Μοντέλο Rayleigh
- Μοντέλο καναλιού του IEEE 802.11 και
- Filtered white Gaussian noise (FWGN) model.
Στο δεύτερο εργαστήριο, θα δούμε απλές υλοποιήσεις ενός OFDM SISO συστήματος καθώς και τα μέτρα ποιότητας του συστήματος.

Τα εργαστήριο θα πραγματοποιηθεί στη νησίδα υπολογιστών που βρίσκεται απέναντι από τη γραμματεία του ΤΗΜΜΥ, την Δευτέρα 2 Δεκεμβρίου και ώρα 11.00-13.00, και την Τρίτη 3 Δεκεμβρίου και ώρα 13.00 - 15.00.

Σημείωση, την Τρίτη το εργαστήριο θα ξεκινήσει ακριβώς στη 13.00.

Στο ethmmy στην καρτέλα Εργασία-Εργαστήριο μπορείτε να δηλώσετε το εργαστήριο. (Αυτό επειδή μας ζήτησαν περίπου το πλήθος των ατόμων που θα βρίσκονται στη νησίδα).

Η παρουσία της ESA έχει ανέβει στο Υλικό Μαθήματος.

Τηλεπικοινωνιακά Νέα :D

Wireless Power Transfer for Electric Vehicles

Researchers from North Carolina State University have developed new technology and techniques for transmitting power wirelessly from a stationary source to a mobile receiver -- moving engineers closer to their goal of creating highway "stations" that can recharge electric vehicles wirelessly as the vehicles drive by.

"We've made changes to both the receiver and the transmitter in order to make wireless energy transfer safer and more efficient," says Dr. Srdjan Lukic, an assistant professor of electrical engineering at NC State and senior author of a paper on the research.

The researchers developed a series of segmented transmitter coils, each of which broadcasts a low-level electromagnetic field. The researchers also created a receiver coil that is the same size as each of the transmitter coils, and which can be placed in a car or other mobile platform. The size of the coils is important, because coils of the same size transfer energy more efficiently.

The researchers modified the receiver so that when it comes into range and couples with a transmitter coil, that specific transmitter coil automatically increases its current -- boosting its magnetic field strength and the related transfer of energy by 400 percent. The transmitter coil's current returns to normal levels when the receiver passes out of the range of the transmitter.
These modifications improve on previous mobile, wireless power transfer techniques.

One previous approach was to use large transmitter coils. But this approach created a powerful and imprecise field that could couple to the frame of a car or other metal objects passing through the field. Because of the magnetic field's strength, which is required to transfer sufficient power to the receiver, these electromagnetic field "leaks" raised safety concerns and reduced system efficiency.

Another previous approach used smaller transmitter coils, which addressed safety and efficiency concerns. But this approach would require a very large number of transmitters to effectively "cover" a section of the roadway, adding substantial cost and complexity to the system, and requiring very precise vehicle position detection technology.
"We tried to take the best from both of those approaches," Lukic says.

Lukic and his team have developed a small, functional prototype of their system, and are now working to both scale it up and increase the power of the system.
Currently, at peak efficiency, the new system can transmit energy at a rate of 0.5 kilowatts (kW). "Our goal is to move from 0.5 kW into the 50 kW range," Lukic says. "That would make it more practical."

Πηγή: http://www.sciencedaily.com/releases/2013/11/131114122200.htm

Space in Videos by ESA

Μιας και σε λίγο καιρό θα αρχίσουμε να ασχολούμαστε με δορυφορικές επικοινωνίες: http://spaceinvideos.esa.int/Videos

Στο Υλικό Μαθήματος στο eThmmy έχει ανέβει η παρουσίαση του πρώτου εργαστηρίου που πραγματοποιήθηκε 02/12/2013.

Στο Υλικό μαθήματος --> Κινητές Επικοινωνίες - Συμπλήρωμα Θεωρίας & Ασκήσεις (2013-2014) έχουν ανέβει οι σημειώσεις για το OFDM

Στο Υλικό μαθήματος στην ενότητα  Εργασία (2013/2014) θα βρείτε παραδείγματα OFDM κωδίκων.

Τηλεπικοινωνιακά νέα  :D

"A New Record for Terahertz Transmission"

Link: http://spectrum.ieee.org/telecom/wireless/a-new-record-for-terahertz-transmission

Ποτε θα επιλεξουμε θεματα?

Μέχρι το τέλος της εβδομάδας θα έχουν ανεβεί τα πάντα στο ethmmy. Θα ενημερώσω σχετικά και εδώ.

Tutorial: Evolution of Reference Signals in LTE from 3GPP Release 8 to 12

Reference signals play a very important role in LTE. With the initial version of LTE as part of 3GPP Release 8 so called cell-specific reference signals (CRS) have been defined. This set of reference signal are utilized for channel estimation and coherent demodulation. In the uplink direction Demodulation Reference Signals (DMRS) were specified fulfilling the exact same purpose. With technology enhancements coming with 3GPP Release 9, such as position estimation based on radio signals as well as dual-layer beamforming intended for TD-LTE, new sets of reference signals have been introduced on top of CRS in the Downlink. And 3GPP Release 10 and 11 introduce even more reference signals, serving different purposes to enable features like higher-order MIMO or Coordinated Multi-Point (CoMP) operation. This tutorial will discuss the evolution of reference signals within the LTE standard from a test and measurement point of view.

link: https://www.comsoc.org/form/tutorial-registration-evolution-reference-signals-lte-3gpp-release-8-12

Οι εργασίες έχουν ανέβει στο υλικό του μαθήματος στο e-thmmy.

Η επιλογή των εργασιών θα γίνει αύριο στην πρώτη ώρα του μαθήματος.

Στο Υλικό Μαθήματος και στην ενότητα Εργασία 2013/2014 μπορείτε να βρείτε τα θέματα και το υλικό εργασιών, καθώς και το ποια εργασία θα κάνει η κάθε ομάδα (Team-Homework.pdf)

Έχει ανέβει και η εργασία της ομάδας 10 στο ethmmy.

Για όποιον θέλει να "ψαχτεί" λίγο σχετικά με το LTE, ένα καλό tutorial: http://www.mastertelecomfaster.com/index.php

Οι  παρουσιάσεις  των  εργασιών  από  τις  ομάδες  θα  γίνουν  την  Τρίτη  14/01/2014.

"Millimeter Wave Mobile Communications for 5G Cellular: It Will Work!"
Από τους:

• THEODORE S. RAPPAPORT
• SHU SUN
• RIMMA MAYZUS
• HANG ZHAO
• YANIV AZAR
• KEVIN WANG
• GEORGE N. WONG
• JOCELYN K. SCHULZ
• MATHEW SAMIMI
• FELIX GUTIERREZ[\li]
  

Είναι ελεύθερο προς όλους (open access) από το IEEEXplore. Μπορείτε να το δείτε στο http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6515173 .

Η αντιστοίχηση εργασίας με ομάδα βρίσκεται στο συνημμένο. Το eThmmy για κάποιο λόγο δεν με αφήνει να μπω, οπότε το ανεβάζω εδώ.

Στο παρακάτω link μπορείτε να βρείτε μία παρουσίαση για OFDM που κάνει αναφορά και σε Synchronization

http://bwrcs.eecs.berkeley.edu/Classes/EE225C/Lectures/Lec16_ofdm.pdf

Και για Channel Estimation:

http://herkules.oulu.fi/isbn9789514298578/isbn9789514298578.pdf

Καλή Χρονιά!!! Χρόνια Πολλά σε όλους μας...

Εύχομαι το 2014 να πραγματοποιήσει κάθε σας επιθυμία και να σας χαρίσει ότι περισσότερο έχετε ανάγκη...

Υγεία, Χαρά, Αγάπη, Τύχη και γενικά ό,τι δεν ήρθε το 2013  ;) 

[Tutorial] Advances in Coordinated Multi-Cell Multi-User MIMO Systems

Abstract

The tutorial begins with a discussion of multiuser MIMO (MU-MIMO) antenna techniques in a point-to-point single-cellular environment. The presenter explains how multi-user scheduling techniques can exploit the degree of Ο λογαριασμός έχει παραβιαστεί, μην ανοίξετε το link. in the user domain to enhance the coverage and capacity of MIMO systems simultaneously.

Next, point-to-multipoint MU-MIMO broadcast systems are covered with an emphasis on the limited feedback issue and beamforming design techniques for MU-MIMO broadcast systems. An explanation covers how the MU-MIMO broadcast techniques can be applied to improve performance of the multi-cellular MIMO systems in an interference-limited environment.

Last, the presenter introduces the state of art coordinated multi-point transmission (CoMP) techniques in 3GPP LTE-advanced or called the collaborative MIMO (Co-MIMO) techniques in IEEE 802.16m WiMAX, and concludes this tutorial by discussing the open issues in this field.

link: https://www.comsoc.org/form/tutorial-registration-advances-coordinated-multi-cell-multi-user-mimo-systems

Υπενθύμιση!

Οι  παρουσιάσεις  των  εργασιών  από  τις  ομάδες  θα  γίνουν  την  Τρίτη  14/01/2014.

Τηλεπικοινωνιακά Νέα!  :D

Scientists have created a molecular communication system that will allow us to send messages and data while we are in tunnels, pipelines and underwater.

Text message using vodka: Molecular communication can aid communication underground, underwater or inside the body

(http://cdn.physorg.com/newman/gfx/news/2013/hgvbuygut.jpg)

Scientists have created a molecular communications system for the transmission of messages and data in challenging environments such as tunnels, pipelines, underwater and within the body.
The technique has a wide range of applications in environments where electromagnetic waves cannot be used, for example in underground structures such as tunnels, pipelines or in underwater environments.
Molecular signalling is a common feature of the plant and animal kingdom – insects for example use pheromones for long-range signalling - but to date continuous data have not been transmitted.
Researchers at the University of Warwick in the UK and the York University in Canada have developed the capability to transform any generic message into binary signals, which in turn is 'programmed' into evaporated alcohol molecules to demonstrate the potential of molecular communications. Their results are published in the open access journal PLOS ONE.
The first demonstration signal was performed in Canada and was 'O Canada,' from the Canadian national anthem. It was sent several metres across open space before it was decoded by a receiver. The hardware is made from off-the-shelf electronics and costs around $100. The scientists believe the simple system could have a wide variety of applications, ranging from communication in hostile underground environments to nanotechnology.

#Invalid YouTube Link#

"We believe we have sent the world's first text message to be transmitted entirely with molecular communication, controlling concentration levels of the alcohol molecules, to encode the alphabets with single spray representing bit 1 and no spray representing the bit 0," says York U doctoral candidate Nariman Farsad, who led the experiment.
Dr Weisi Guo from the School of Engineering at the University of Warwick said: "Imagine sending a detailed message using perfume – it sounds like something from a spy thriller novel, but in reality it is an incredibly simple way to communicate.
" Of course people have achieved short ranged signalling using chemicals, but we have gone to the next level and successfully communicated continuous and generic messages over several metres.
"Signalling or cues are something we see all the time in the natural world - bees for example use chemicals in pheromones to signal to others when there is a threat to the hive.
"In the modern human world, our method won't replace electromagnetic waves which transmit the bulk of our data, but there are some areas where conventional communications systems are not particularly well-adapted.
"For example, inside tunnels, pipelines or deep underground structures, chemical signals can offer a more efficient way of transmitting sensor data, such as those collected to monitor the health of structures and processes.
"Potential targeted applications include wireless monitoring of sewage works and oil rigs. This could prevent future disasters such as the bus-sized fatberg found blocking the London sewage networks in 2013, and the Deepwater Horizon oil spill in 2010."
"They can also be used to communicate on the nano scale, for example in medicine where recent advances mean it's possible to embed sensors into the organs of the body or create miniature robots to carry out a specific task such as targeting drugs to cancer cells.
"On these tiny scales and in special structural environments, there are constraints with electromagnetic signals such as the ratio of antenna size to the wavelength of the signal, which chemical communication does not have.
"Molecular communication signals are also biocompatible and require very little energy to generate and propagate."
The team will now set up a company which aims to bring a range of academic and industrial products to the market.


Read more at: http://phys.org/news/2013-12-messages-molecules-aid-underground-underwater.html#jCp


link: http://phys.org/news/2013-12-messages-molecules-aid-underground-underwater.html

Τηλεπικοινωνιακά Νέα!  :D

LTE-Advanced Is the Real 4G

More network capacity, faster data speeds, and better coverage will come from LTE-Advanced mobile technologies.

(http://spectrum.ieee.org/img/lte-advantage-illo-1388157451950.jpg)


Read more at: http://spectrum.ieee.org/telecom/standards/lte-advanced-is-the-real-4g

Οι παρουσιάσεις των εργασιών θα γίνουν την Τρίτη 14/01/2014 και ώρα 13:00-15:00 στην Αίθουσα Α7.


Όσοι κάνουν εργασία θα πρέπει να παραδώσουν την αναφορά τους έως την ημερομηνία εξέτασης του μαθήματος.

Μάθημα Δευτέρα 13/01/2014

Τη Δευτέρα θα γίνει μάθημα μόνο την πρώτη ώρα (11:00 - 11:45) και θα ξεκινήσει 11:00 ακριβώς, με θέμα: "Απώλειες στις Δορυφορικές Επικοινωνίες", από τον Α. Μπουλογεώργο.

Τη 2η ώρα, μπορείτε να παρακολουθήσετε την δημόσια υποστήριξη του διδακτορικού του Β. Καπινά που θα γίνει στην αίθουσα Γενικών Συνελεύσεων και σχετίζεται με MIMO συστήματα.

Τηλεπικοινωνιακά Νέα!  :D

Greening the Cloud Using Renewable-Energy-Aware  Service Migration


link: http://www.comsoc.org/sites/default/files/webfm/freearticle/free.pdf

CES 2014 Trends: Wireless Networks Need to Learn to Cooperate

As the demand for bandwidth increases, wireless engineers are trying to figure out how to efficiently use all available networks, without sacrificing privacy and security


The big trends this year were an increased focus on cooperation and hand-offs between networks, an increased focus on privacy and security, and questions about how to make money from it all.


Transcript:

Josh Romero: Hi, I’m Josh Romero for IEEE Spectrum’s “Techwise Conversations”.  Today we’ll be talking with Stephen Cass who’s part of IEEE Spectrum’s team that’s live in Las Vegas covering CES 2014.  He’s here to talk about the latest trends in wireless.  Good morning Stephen—how’s Las Vegas?

Stephen Cass: Busy.  It’s only 8:00 in the morning, and already the place is getting pretty crazy, so it’s going to be another big day here at CES.

Josh Romero: I want to know what’s next and new with wireless systems. What have been the trends you’ve been hearing about the most this year, what are the themes emerging from the show?

Stephen Cass:  The big trend is everybody having to get their wireless technologies working together.  I think, in the past, you had one device and it might have one or maybe two wireless technologies.  If you had a cellular phone, it might have just had a 3G or 4G connection and Bluetooth; if you had a laptop it had Wi-Fi. And I think now we’re moving to a world where every device will be expected to negotiate multiple wireless systems, so you can move very seamlessly from place to place.  The reason why everybody—from device manufacturers to the cellphone carriers—are interested in this, is being able to deal with huge amounts of traffic. The idea is the ability to offload traffic.  Most traffic occurs in buildings, so if you’re on a cellphone and you’re doing a streaming video call, there’s not really a need to send that traffic to a cellphone tower down the block. Instead, why not pick it up inside the building, where all the other people who are trying to do video calls are.  So it’s really about how to very seamlessly hand off between these different technologies. Of course, a big challenge with that is the interference; now you’re combining multiple radios into one board or one chip, and with five or six radios you’re talking about interference within the device. And then you’ve got to deal with huge amounts of interference between users on the scale of city block.  So that’s kind of the big technical challenge, but there does seem to be huge momentum to overcome this.

Josh Romero:  So there’s increased cooperation between these previously separate networks at this point?

Stephen Cass: Yes exactly.  So for instance, the Wi-Fi Alliance now is in talks with the near-field communications community to talk about ways that you could maybe tap with your phone and get access to a wireless point.  The cellular people are also talking with operators of commercial Wi-Fi access points, like the type you might find in airports and hotels, again about how to seamlessly hand-off between the cellular network and the local Wi-Fi network.

Josh Romero: This is kind of an evolution of the wireless trends that we’ve been seeing for a couple years, but is there anything particularly new or distinctive that stood out to you at this year's show?

Stephen Cass: Yeah. I think one is the emphasis on control and privacy. In the past, it has always been, “Sure it’s there,” but it’s only imagined that very paranoid, or hardcore, or sort of techies would want to use it.  I think that recent concerns about surveillance has changed that. So everyone is taking security and privacy very seriously.  And how do you guarantee that, especially when you’re moving from all these different technologies and all these different networks?  How do you expose that control to users in a way that makes sense, that they don’t feel that things are being done underneath the hood that they don’t like, while at the same time not making it completely overwhelming so that every two seconds you’re hitting an “I agree to this” or “I agree to that” or "OK these terms of services" notice on your phone.  So that’s been a big issue.

So one issue where you have all these things working together, of course, is monetization and “How do we create a business model?”  Another issue that I asked about is net neutrality.  In the past, wireless mobile, because of it’s limited spectrum, has always made a play for saying that the rules of network neutrality shouldn’t quite apply to them, that there should be exceptions, they should be allowed to do  traffic shaping, so that everybody can make their cellphone call without getting swamped by one person doing a Bit Torrent.  So there are still elements of that idea, that spectrum is very scarce and very constrained but it will be interesting to see how it plays out when I move from fixed wireless systems like Wi-Fi, or the new system called Wi-Gig which is emerging in the next few years, onto cellular network and how that traffic is handled.  I think there’s a lot of work to be done, both technically, and with the business models and some of the technical administration models.

Josh Romero: So it sounds like the big trends this year were increased focus on cooperating and handoffs between networks, and increased focus on privacy and security—is that about right?

Stephen Cass:  I think that’s about right—and also an increased emphasis on how you would make money off it all.

Josh Romero: Great, thanks Stephen. We’ll look forward to hearing more of your reporting from the rest of the show.

Stephen Cass: Thanks Josh.

Josh Romero: We’ve been talking with Stephen Cass, who’s part of IEEE Spectrum’s team covering CES 2014.  For all CES coverage, check out the website.

For Techwise Conversations I’m Josh Romero.

This interview was recorded 8 January 2014.

Audio engineer: Francesco Ferorelli

Image: iStock

NOTE: Transcripts are created for the convenience of our readers and listeners and may not perfectly match their associated interviews and narratives. The authoritative record of IEEE Spectrum’s audio programming is the audio version.

Highlights from ”Wi-Fi to NFC: What’s Next for Wireless“ Session


Source: http://spectrum.ieee.org/podcast/telecom/wireless/ces-2014-trends-wireless-networks-need-to-learn-to-cooperate

LTE Advanced—Leading in chipsets and evolution

link: http://www.qualcomm.com/sites/default/files/document/files/wireless-networks-lte_advanced-leading_in_chipsets_and_evolution.v6.20130827.pdf

Στο παραπάνω link μπορείτε να βρείτε μία παρουσίαση της Qualcomm σχετικά με LTE-Advanced
και τεχνικές, όπως:
- Carrier Aggrigation
- MIMO κ.α.
σε Heterogeneous Networks (Ετερογενή δίκτυα), που χρησιμοποιούνται για αύξηση των:
- data rate
- spectal efficiency κ.α.

Extending the benefits of LTE Advanced to unlicensed spectrum

Description:

For operators to meet the anticipated 1000x increase in data traffic, deploying more small cells and utilizing all spectrum resources are key. Although licensed spectrum is the foundation, bandwidth-rich unlicensed spectrum around 5 GHz band can be used to effectively augment the capacity. The question is how to best opportunistically utilize it.

Extending the benefits of LTE Advanced to unlicensed spectrum brings its basic tenets of high-efficiency and robust mobility, while also making it a seamless extension of the larger LTE Advanced network. That means higher performance for operators and better broadband experience for users, and a common unified network for all spectrum types.

Presentation link: http://www.qualcomm.com/media/documents/extending-benefits-lte-advanced-unlicensed-spectrum

Σχετικά με την Εργασία και την Παρουσίαση

Η παρουσίαση την Τρίτη 13.00 - 15.00 είναι υποχρεωτική και δεν μπορεί να υπάρξει αναβολή. Οι ομάδες θα πρέπει να έχουν ετοιμάσει μία παρουσίαση διάρκειας 10-15' το πολύ (~10-15 διαφάνειες) στις οποίες αν δεν έχουν ολοκληρώσει την εργασία θα συμπεριλάβουν τα:
- πρόβλημα που εξετάζουν και ανάγκη επίλυσης (π.χ. Ποια η ανάγκη για Channel Estimation ή Sychronization)
- μοντέλο του συστήματος που εξετάζουν (SISO OFDM με block που θα δείχνουν που θα εφαρμόσουν (-ζουν) τις διάφορες τεχνικές)
- σύντομη παρουσίαση των καναλιών που έχουν και πως τα υλοποίησαν
- τεχνικές που θα χρησιμοποιήσουν και τι έχουν υλοποιήσει από αυτές
- ότι αποτελέσματα έχουν πάρει
Καλό είναι να αναφερθούν σε "κολλήματα" και προβλήματα που έχουν τόσο στις τεχνικές όσο και στην υλοποίηση, ώστε να γίνει συζήτηση και να βρεθούν λύσεις που θα σας βοηθήσουν να ολοκληρώσετε την εργασία.

Το παραπάνω αποτελεί μία γενική πρόταση στο πως μπορείτε να δομήσετε την παρουσίαση σας. Μπορείτε να ξεφύγετε όσο θέλετε.  ;)

4G LTE-Advanced Technology Overview

4G LTE refers to the evolved version of LTE that is being developed by 3GPP to meet or exceed the requirements of the International Telecommunication Union (ITU) for a true fourth generation radio-communication standard known as IMT-Advanced. 4G LTE, whose project name is LTE-Advanced, is being specified initially in Release 10 of the 3GPP standard, with a functional freeze targeted for March 2011. The 4G LTE standard will continue to be developed in subsequent releases. In October 2009, the 3GPP Partners formally submitted LTE-Advanced to the ITU as a candidate for 4G IMT-Advanced1. The certified technology specifications for IMT-Advanced are expected to be published in early 20112.

Key ITU requirements for IMT-Advanced that 4G LTE will support include the following3:

A high degree of common functionality worldwide while retaining the flexibility to support a wide range of local services and applications in a cost-efficient manner
Compatibility of services within IMT and with fixed networks
Capability for interworking with other radio systems
High quality mobile services
User equipment suitable for worldwide use
User-friendly applications, services, and equipment
Worldwide roaming capability
Enhanced peak data rates to support advanced mobile services and applications (100 Mbps for high mobility and 1 Gbps for low mobility)
3GPP cites an additional reason to align 4G LTE with IMT-Advanced: IMT-conformant systems will be candidates for any new spectrum bands identified by the WRC-07 (World Radiocommunication Conference). 4

3GPP Considerations

3GPP Technical Report (TR) 36.913, "Requirements for Further Advancements for E-UTRA (LTE-Advanced)," describes the requirements for further advancement of the LTE E-UTRA (air interface) and E-UTRAN (air interface network).5 These requirements are based on those of the ITU for IMT-Advanced as well as on 3GPP operators' own requirements for advancing LTE. Major technical considerations for 4G LTE development include:

Continual improvement to the LTE radio technology and architecture
Scenarios and performance requirements for interworking with legacy radio access technologies
Backward compatibility of LTE-Advanced with LTE. An LTE terminal should be able to work in an LTE-Advanced network and vice versa. Any exceptions will be considered by 3GPP.
Account taken of recent WRC-07 decisions for new IMT spectrum as well as existing frequency bands to ensure that LTE-Advanced geographically accommodates available spectrum for channel allocations above 20 MHz. Also, requirements must recognize those parts of the world in which wideband channels are not available.
System performance requirements

The system performance requirements for 4G-LTE will in most cases exceed those of IMT-Advanced. The 1 Gbps peak data rate required by the ITU will be achieved in 4G LTE using 4x4 MIMO and transmission bandwidth wider than approximately 70 MHz. In terms of spectral efficiency, today's LTE (Release 8) satisfies the IMT-Advanced requirement for the downlink, but the bps/Hz must be doubled in LTE-Advanced to meet the 4G requirement.


Table 1 compares the spectral efficiency targets for LTE, LTE-Advanced, and IMT-Advanced. Note that the peak rates for LTE-Advanced are substantially higher than the IMT-Advanced requirements, which highlights a desire to drive up peak performance in 4G LTE, although targets for average performance are closer to ITU requirements. However, TR 36.913 states that targets for average spectral efficiency and for cell-edge user throughput efficiency should be given higher priority than targets for peak spectral efficiency and other features such as VoIP capacity.5 Thus 4G LTE work will be focused on the challenges of raising average and cell-edge performance.

Table 1. Performance targets for LTE, Advanced-LTE, and IMT-Advanced6
(http://cp.home.agilent.com/upload/cmc_upload/ck/zz-migration/images/Performance_targets_LTE.jpg)


Performance targets for LTE Advanced-LTE IMT Advanced

White Space

The flexibility of spectrum is another important consideration. Actual available spectra differ by region and country. 3GPP is studying the feasibility of various deployment scenarios for spectrum allocation.

3GPP solution proposals

Proposed solutions for achieving LTE-Advanced performance targets are defined in 3GPP TR 36.814, "Further Advancements for E-UTRA Physical Layer Aspects."7 The following features are supported in LTE-Advanced proposals:

Carrier and spectrum aggregation--The lack of contiguous spectrum for wider transmission bandwidths (to 100 MHz) forces the use of carrier aggregation to meet peak data rate and spectrum flexibility requirements. Aggregation of contiguous and non-contiguous component carriers is allowed.
Enhanced uplink multiple access--The addition of N-times DFT-spread OFDM (also known as "clustered SC-FDMA") will satisfy increased data rate requirements while maintaining backward-compatibility with LTE.
Higher order MIMO transmission--Up to 8x8 MIMO in the downlink and 4x4 MIMO in the uplink is used to reach peak data rates. Beamforming with spatial multiplexing is being considered to increase data rates, coverage, and capacity.
Coordinated multipoint (CoMP) transmission and reception--This MIMO variant is intended to improve performance for high data rates, cell‐edge throughput, and system throughput. Is being studied for Release 11.
Relaying--In-channel relays receive, amplify, and retransmit downlink and uplink signals to improve coverage. More advanced relaying enables the use of some subframes in a channel to carry backhaul traffic. The main use cases for relays are to improve urban or indoor throughput, to add dead zone coverage, or to extend coverage in rural areas.
Other proposals related to 4G LTE address the support needs of an increasingly heterogeneous network that combines macro-, micro-, pico-, and femtocells, along with repeaters and relay nodes. Work is ongoing to develop advanced methods of radio resource management including new self-optimizing network (SON) features. The 4G LTE specifications also continue to focus on the use of femtocells and home base stations (eNBs) as a means of improving network efficiencies and reducing infrastructure costs.

Industry-supported field trials are already demonstrating the viability of many of the technical concepts in LTE-Advanced, and 3GPP's submission to the ITU included a self-evaluation of its proposals concluding that LTE-Advanced meets all IMT-Advanced requirements for being officially certified as 4G. Nevertheless, the timing of 4G LTE deployment is difficult to predict and will likely be dependent on industry demand and the success of today's Release 8 and 9 LTE rollouts.

Design and test challenges

As an evolution of LTE, LTE-Advanced will pose similar challenges to design and test engineers. The LTE standard is new and quite complex, with multiple channel bandwidths, different transmission schemes for the downlink and uplink, both frequency and time domain duplexing (FDD and TDD) transmission modes, and use of MIMO antenna techniques. LTE and LTE-Advanced will likely have to co-exist with 2G and 3G cellular systems for some time, so interworking necessities and potential interference remain important issues. In a difficult radio environment, LTE sets the bar for performance targets very high, and LTE-Advanced raises it even higher.

Some new challenges are anticipated with the solutions proposals for LTE-Advanced. For example, carrier aggregation will undoubtedly pose major difficulties for the UE, which must handle multiple simultaneous transmit and receive chains. The addition of simultaneous non-contiguous transmitters create a highly challenging radio environment in terms of spur management and self-blocking. Simultaneous transmit or receive with mandatory MIMO support will add significantly to the challenge of antenna design.

The introduction of clustered SC-FDMA in the uplink allows frequency selective scheduling within a component carrier for better link performance, and the PUCCH and PUSCH can be scheduled together to reduce latency. However, clustered SC-FDMA increases peak to average power ratio (PAR) by several dB, adding to transmitter linearity issues. Simultaneous PUCCH and PUSCH also increase PAR. Both features create multi-carrier signals within the channel bandwidth and increase the opportunity for in-channel and adjacent channel spur generation. Test tools will need to be enhanced with capability for signal generation and analysis of multicarrier signals in 4G power amplifiers.

Higher order MIMO will increase the need for simultaneous transceivers in a manner similar to carrier aggregation. However, MIMO has an additional challenge in that the number of antennas will multiply, and the MIMO antennas will have to be de-correlated. It will be especially difficult to design multiband, MIMO antennas with good de-correlation to operate in the small space of a 4G UE. Conducted testing of higher order MIMO terminals will no longer be usable for predicting actual radiated performance in an operational network. A study item in Release 9 of the 3GPP standard is looking at MIMO over the air testing as an alternative.

From the UE perspective, relaying is completely transparent. In this case the challenge is all on the network side. For the system to work, the link budget from the relay node to the macro eNB must be good, which implies line of site positioning. The main operational challenge in getting relaying to work will be in the management of the UE. The UE must be instructed to hand over to a relay node that is within range and release the relay node when the UE goes out of range. If this process is not well managed, the performance of the cell could actually go down, not up as intended.

These are just a few of the challenges that 4G LTE will present wireless design and test engineers. As the 4G specifications are published and the certification process moves ahead, so too will test vendors have to increase the capability of their products and invent ingenious new ways to verify the performance of the evolving 4G systems.

1 Press release, "3GPP Partners propose IMT-Advanced radio," Geneva, October 8, 2009.

2 3GPP Americas, "Mobile Broadband Innovation Path to 4G: Release 9, Release 10 and Beyond," www.3Gamericas.org

3 ITU-R M [IMT-TECH], "Requirements related to technical performance for IMT-Advanced radio interface(s)," August 2008.

4 3GPP web site, 3GPP - LTE-Advanced. 3GPP - LTE-Advanced

5 3GPP TR 36.913 V9.0.0 (2009-12), www.3gpp.org/ftp/Specs/archive/36_series/36.913

6 Rumney, Moray. LTE and the Evolution to 4G Wireless: Design and Measurement Challenges, p.416. 2009, Agilent Technologies Publication.

7 3GPP TR 36.814, www.3gpp.org/ftp/Specs/archive/36_series/36.814/


Source: http://www.home.agilent.com/agilent/editorial.jspx?ckey=1905163&id=1905163%22&lc=eng&cc=IN

Συμπληρωματικά:

Οι  ομάδες  που  ασχολούνται  με  την  εργασία  καλούνται  να  στείλουν  mail  στο  ampoulog@auth.gr  για  την  επιβεβαίωση  της  παρουσίασης  ή  να  το  δηλώσουν  στο  μάθημα  της  Δευτέρας  13/01/2014. 

Επίσης,  έως  και  μία  ώρα  πριν  την  παρουσίαση  οι  ομάδες  θα  πρέπει  να  στείλουν  τις  διαφάνειες  στο  παραπάνω  e-mail  σε  μορφή  .ppt,  .pptx,  .odp  ή  ο,τι  άλλο  θέλουν,  αλλά  και  .pdf,  διαφορετικά  θα  πρέπει  να  φροντίσουν  να  έχουν  την  παρουσίαση  μαζί  τους  σε  flash  drive.     

Για εφαρμογές (και όχι μόνο) του OFDM:
http://web.ee.ccu.edu.tw/~wl/ofdm/pdfnew/Chapter%208%20OFDM%20Applications.pdf
http://iosrjournals.org/iosr-jmce/papers/vol1-issue1/B0110711.pdf
http://engold.ui.ac.ir/~sabahi/Advanced%20digital%20communication/OFDM%20and%20Its%20Wireless%20Applications-%20A%20Survey.pdf
http://www.altera.com/literature/an/an503.pdf


Για όποιον ενδιαφέρεται να δει και κάποιες πιο ενεργειακές εφαρμογές του OFDM.


OFDM-Based High Speed Narrowband PLC Approved for Smart Metering and Smart Grids

Παρουσίαση στο: http://cms.comsoc.org/SiteGen/Uploads/Public/Docs_ISPLC_2009_/keynotes/2009-03-30_ISPLC-Keynote_V1d.pdf

και:
http://www.maximintegrated.com/products/powerline/pdfs/G3-PLC-Physical-Layer-Specification.pdf
http://www.idosi.org/wasj/wasj20(9)12/6.pdf

Στο υλικό μαθήματος -> Πρόσθετες σημειώσεις θεωρίας μπορείτε να βρείτε κάποια επιπλέον πράγματα για OFDM.

Cooperative Communication in Wireless Networks

Για όσους ενδιαφέρονται για Cooperative Communications!

link: http://xanthippi.ceid.upatras.gr/courses/mobile/2006_07/Cooperative.pdf

Cooperative Communications in Resource-Constrained Wireless Networks

link: http://xanthippi.ceid.upatras.gr/courses/mobile/2009_10/cooperative_resource.pdf

Cooperative Communications in Mobile Ad-Hoc Networks: Rethinking the Link Abstraction

link: http://www3.nd.edu/~jnl/pubs/crc-coop-chapter.pdf

Υπενθύμιση!

Καλησπέρα.

Το βιβλίο που παραθέτω μου φάνηκε ιδιαίτερα επικοδομητικό και πιστεύω ότι μπορεί να βοηθήσει και εσάς όχι μόνο στην μελέτη αλλά και στην εργασία.

Μπορείτε να δείτε ένα preview πριν το κατεβάσετε: http://books.google.gr/books/about/MIMO_OFDM_Wireless_Communications_with_M.html?id=6HwAoeuMr3kC&redir_esc=y

τι έγινε?
δεν πρόλαβα να το κατεβάσω και διαγράφηκε

Έκανα βλακεία με τα πνευματικά δικαιώματα και τα σχετικά...

Αλλά για ρίξτε μια ματιά εδώ, http://www.freebookspot.es/

Ο δικός μου τρόπος,

(Είναι πιο εύκολος από ότι φαίνεται)

Έχετε τα στοιχεία του βιβλίου (http://books.google.gr/books/about/MIMO_OFDM_Wireless_Communications_with_M.html?id=6HwAoeuMr3kC&redir_esc=y)
Έχετε την πηγή(http://www.freebookspot.es/).
Μόλις το βρείτε θα σας βγάλει μια λίστα με links(i.e. http://ryushare.com/ea492c9a57d/04708256...)
Αυτό το link σας κάνει redirect σε μια σελίδα όπου μπορείτε να το κατεβάσετε.
Σε αυτή την σελίδα κάν'τε scroll down και βρείτε ένα κουμπί που λέει "Low Speed Download"
Περιμένετε ένα λεπτό.
Μετά βάλτε την λέξη που σας ζητάει για να τσεκάρει εάν είστε botακι.
Μετά θα δημιουργήσει ένα link για να κάνετε Download.

Φυσικά μπορείτε να κάνετε τα δικά σας και να το βρείτε μέσα από τις δικές σας πηγές.(ΗΜΜΥ είστε)

Σε περίπτωση που δεν τα καταφέρετε πάλι υπάρχει τρόπος...Στο μάθημα!

Heterogeneous Networks in LTE

by Jeanette Wannstrom, masterltefaster.com and Keith Mallinson, WiseHarbor

Effective network planning is essential to cope with the increasing number of mobile broadband data subscribers and bandwidth-intensive services competing for limited radio resources. Operators have met this challenge by increasing capacity with new radio spectrum, adding multi-antenna techniques and implementing more efficient modulation and coding schemes. However, these measures alone are insufficient in the most crowded environments and at cell edges where performance can significantly degrade. Operators are also adding small cells and tightly-integrating these with their macro networks to spread traffic loads, widely maintain performance and service quality while reusing spectrum most efficiently.

One way to expand an existing macro-network, while maintaining it as a homogeneous network, is to “densify” it by adding more sectors per eNB or deploying more macro-eNBs. However, reducing the site-to-site distance in the macro-network can only be pursued to a certain extent because finding new macro-sites becomes increasingly difficult and can be expensive, especially in city centres. An alternative is to introduce small cells through the addition of low-power base stations (eNBs, HeNBs or Relay Nodes (RNs)) or Remote Radio Heads (RRH) to existing macro-eNBs. Site acquisition is easier and cheaper with this equipment which is also correspondingly smaller.

Small cells are primarily added to increase capacity in hot spots with high user demand and to fill in areas not covered by the macro network – both outdoors and indoors. They also improve network performance and service quality by offloading from the large macro-cells. The result is a heterogeneous network with large macro-cells in combination with small cells providing increased bitrates per unit area. See Figure 1.

(http://www.3gpp.org/images/articleimages/Hetnet/fig001.jpg)

Heterogeneous network planning was already used in GSM. The large and small cells in GSM are separated through the use of different frequencies. This solution is still possible in LTE. However, LTE networks mainly use a frequency reuse of one to maximize utilization of the licensed bandwidth.

In heterogeneous networks the cells of different sizes are referred to as macro-, micro-, pico- and femto-cells; listed in order of decreasing base station power. The actual cell size depends not only on the eNB power but also on antenna position, as well as the location environment; e.g. rural or city, indoor or outdoor . The HeNB (Home eNB) was introduced in LTE Release 9 (R9). It is a low power eNB which is mainly used to provide indoor coverage, femto-cells, for Closed Subscriber Groups (CSG), for example, in office premises. See Figure 2.

Specific to HeNBs, is that they are privately owned and deployed without coordination with the macro-network. If the frequency used in the femto-cell is the same as the frequency used in the macro-cells, and the femto-cell is only used for CSG, then there is a risk of interference between the femto-cell and the surrounding network.

The Relay Node (RN) is another type of low-power base station added to the LTE R10 specifications. The RN is connected to a Donor eNB (DeNB) via the Un radio interface, which is based on the LTE Uu interface. See Figure 2. When the frequencies used on Uu and Un for the RN are the same, there is a risk of self interference in the RN. From the UE perspective the RN will act as an eNB, and from the DeNB’s view the RN will be seen as a UE. As also mentioned, RRHs connected to an eNB via fibre can be used to provide small cell coverage.

(http://www.3gpp.org/images/articleimages/Hetnet/fig002.jpg)

Introducing a mix of cell sizes and generating a heterogeneous network adds to the complexity of network planning. In a network with a frequency reuse of one, the UE normally camps on the cell with the strongest received DL signal (SSDL), hence the border between two cells is located at the point where SSDL is the same in both cells. In homogeneous networks, this also typically coincides with the point of equal path loss for the UL (PLUL) in both cells. In a heterogeneous network, with high-power nodes in the large cells and low-power nodes in the small cells, the point of equal SSDL will not necessarily be the same as that of equal PLUL. See Figure 3.

(http://www.3gpp.org/images/articleimages/Hetnet/fig003.jpg)

A major issue in heterogeneous network planning is to ensure that the small cells actually serve enough users. One way to do that is to increase the area served by the small cell, which can be done through the use of a positive cell selection offset to the SSDL of the small cell. This is called Cell Range Extension (CRE). See Figure 4.

http://www.3gpp.org/images/articleimages/Hetnet/fig004.jpg

A negative effect of this is the increased interference on the DL experienced by the UE located in the CRE region and served by the base station in the small cell. This may impact the reception of the DL control channels in particular.



Περισσότερα στο: http://www.3gpp.org/technologies/keywords-acronyms/1576-hetnet

Παρακαλούνται  οι  φοιτητές  που  παρακολούθησαν  το  μάθημα  να  συμπληρώσουν    ηλεκτρονικά  το  δελτίο  αξιολόγησης  του  μαθήματος  μέχρι  τις  19/2/2014.   

Η  συμπλήρωση  του  δελτίου  μπορεί  να  γίνει  από  την  ιστοσελίδα  της  ΜΟΔΙΠ    (http://qa.auth.gr)  κάνοντας  "ΕΙΣΟΔΟ"    στο  σύστημα  με  τον  πανεπιστημιακό  σας  λογαριασμό  και  επιλέγοντας  Ηλεκτρονική  αξιολόγηση  ή  απευθείας  μέσω  του  συνδέσμου  (https://login-idp.auth.gr/idp/Authn/UserPassword).

http://www.youtube.com/watch?v=ATswqszCuMI

http://www.youtube.com/watch?v=P7nhgX0ppek

http://www.youtube.com/watch?v=Wn-BV9Zp8Pk

http://www.youtube.com/watch?v=JpzAFb30lKk

http://www.youtube.com/watch?v=yxYzjHBKNcA

http://www.youtube.com/watch?v=_vfzAL5L29Y

http://www.youtube.com/watch?v=QPydHE3a8Kw

http://www.youtube.com/watch?v=xDmQvJVJg8Y

http://www.youtube.com/watch?v=A58qMscr9ys

http://www.youtube.com/watch?v=2MW-4VgLkus

http://www.youtube.com/watch?v=BnFyzZGWuYs

http://www.youtube.com/watch?v=fTLEyYDm3Ck

http://www.youtube.com/watch?v=HD_sjhwFXxw

http://www.youtube.com/watch?v=r52M7891iP0

http://www.youtube.com/watch?v=5u_ey520WSQ

Τα παραπάνω αφορούν δορυφορικά συστήματα!

LTE Tutorial Παρουσίαση

http://kang.nt.e-technik.tu-darmstadt.de/nt/fileadmin/nas/Mitarbeiter/Marius_Pesavento/LTE_tutorial_FemtoForum_part1.pdf

http://kang.nt.e-technik.tu-darmstadt.de/nt/fileadmin/nas/Mitarbeiter/Marius_Pesavento/LTE_tutorial_FemtoForum_part2.pdf

Στις παραπάνω παρουσιάσεις μπορείτε να δείτε την χρήση κάποιων τεχνικών που συζητήσαμε κατά τη διάρκεια του μαθήματος στο LTE.

Ανακοίνωση

Τη Δευτέρα 20/01/2014 και την Τρίτη 21/01/2014 τα μαθήματα θα γίνουν κανονικά!

Λίγο πιο εκτός του μαθήματος, αλλά αξίζει να δείτε το βίντεο της διάλυσης του Challenger για εγκυκλοπαιδικούς σκοπούς.

Ιανουάριος 1986: Η διάλυση του Challenger στον αέρα καρέ-καρέ 13 εικόνες από την καταστροφή του διαστημικού λεωφορείου

28 Ιανουαρίου 1986. Το διαστημικό λεωφορείο Challenger διαλύεται 73 δευτερόλεπτα μετά την εκτόξευση του, σκοτώνοντας και τα επτά μέλη του πληρώματος. Ήταν η πρώτη φορά που οι ΗΠΑ έχασαν αστροναύτες κατά την πτήση.  Ανάμεσα στους νεκρούς αστροναύτες και μια δασκάλα η Κρίστα Μακόλιφ. Στο πρόσωπο της η Αμερική θα δει ένα νέο σύμβολο.   Ο ελαττωματικός σχεδιασμός της ασπίδας των πυραύλων και ο κρύος καιρός ήταν μερικοί από τους παράγοντες που θεωρήθηκαν υπεύθυνοι για την έκρηξη. Το γεγονός παρακολούθησαν από την τηλεόραση εκατομμύρια άνθρωποι:

(http://www.lifo.gr/icache/640/458/1/616159_challenger3.jpg)

(http://www.lifo.gr/icache/640/458/1/616160_challenger4.jpg)

(http://www.lifo.gr/icache/640/896/1/616161_challenger5.jpg)

(http://www.lifo.gr/icache/640/896/1/616162_challenger6.jpg)

(http://www.lifo.gr/icache/640/896/1/616163_challenger7.jpg)

(http://www.lifo.gr/icache/640/896/1/616164_challenger8.jpg)

(http://www.lifo.gr/icache/640/896/1/616165_challenger9.jpg)

(http://www.lifo.gr/icache/640/896/1/616166_challenger10.jpg)

(http://www.lifo.gr/icache/640/458/1/616167_challenger11.jpg)

(http://www.lifo.gr/icache/640/896/1/616168_challenger12.jpg)

(http://www.lifo.gr/icache/640/896/1/616169_challenger13.jpg)

(http://www.lifo.gr/icache/640/417/1/616170_challenger14.jpg)

http://www.youtube.com/watch?v=5hQL0NWS1Rc

http://www.youtube.com/watch?v=G2xRNAwgiZ4

Πηγή: http://www.lifo.gr/team/lola/45403

Καλησπέρα σε όλους,

Στο παρακάτω link μπορείτε να βρείτε ένα pdf, με τίτλο:
το οποίο περιγράφει το πρότυπο DVB-S2 από την πλευρά του Physical Layer.

Θεωρώ ότι έχει ενδιαφέρον να δείτε την εφαρμογή των εννοιών που συναντήσατε στα μαθήματα του τομέα, π.χ.
- Carrier-to-(Noise+Interference) ratio μία άλλη ονομασία για το SNIR,
- RC filters frequency transfer function, όπου RC raised cosine, (θυμίζω Ψηφιακές Τηλεπικοινωνίες ΙΙ)
- Modulations
- Interference κ.α.
ώστε να συνδυάσετε τις διάφορες πληροφορίες ;)

http://www.etsi.org/deliver/etsi_en/302300_302399/302307/01.03.01_60/en_302307v010301p.pdf
 

Δορυφορικά Νέα  :D

Alphasat's Pioneering High-frequency hosted payload set for experiments

European scientists can now begin probing unexplored frequencies, as mega telecom satellite Alphasat’s ‘Aldo Paraboni Q/V Band’ hosted payload has been given the green light to begin experiments. Six months after launch, the payload has undergone many commissioning and in-orbit tests before receiving the go-ahead to start operations. The Q/V-band mission, named after the late Italian scientist Aldo Paraboni who inspired it, is one of four technology demonstration payloads carried by Alphasat. It is dedicated to exploring the higher-frequency Q- and V-bands at 38 and 48 GHz.

It is necessary to look into using the higher frequencies for carrying data because our current information highways – the Ku- and Ka-bands from 12 to 18 GHz and 26.5 to 40 GHz, respectively – are becoming increasingly congested. Expanding the range of frequencies we can use means more bandwidth availability.

Περισσότερα στο: http://www.esa.int/Our_Activities/Telecommunications_Integrated_Applications/Alphasat/Alphasat_s_pioneering_high-frequency_hosted_payload_set_for_experiments

MIMO and Coordinated MultiPoint (CoMP) Transmission/Reception in LTE-Advanced

link: https://www.nttdocomo.co.jp/english/binary/pdf/corporate/technology/rd/technical_journal/bn/vol12_2/vol12_2_020en.pdf

Δείτε στο Figure 1 4x4 Single User MIMO σύστημα, καθώς και τα figures που αφορούν τις τεχνικές multiplexing.

Τηλεπικοινωνιακά νέα  :D  :o

New "Look And Link" Wireless Technology Enables Device-to-Device Links By Pointing

(http://spectrum.ieee.org/img/LTEphonetalkGettyImages-1390608442887.jpg)

See: http://spectrum.ieee.org/tech-talk/telecom/wireless/new-look-and-link-wireless-technology-enables-devicetodevice-links-by-pointing

Tutorial  ;)
[/b]
The worldwide incentives to evolve to a low-carbon economy are driving the development of smarter, ICT-enabled power grids. Realizing this next-generation power grid requires cooperation between previously separated industries (telecom, power technology, sensor technology, GIS technology, etc.). With many stakeholders involved, and many (legacy) systems that will get impacted, communication between these stakeholders and systems becomes a key aspect. Unlike many other systems, a massive amount of data will need to be transformed into real-time intelligence, which should drive one of the most critical grids of our society. Many questions and challenges arise with respect to resilience, compatibility, self-management, etc. A panel of experts from industry, university and government shares the issues that are currently addressed, and provides their view on the future challenges.
(https://www.comsoc.org/files/Career/free-tutorials/SmartGrid.jpg)

link: https://www.comsoc.org/form/tutorial-registration-cross-industry-view-smart-grid-communications

28/2 μάλλον!!

Ναι 28/02/2014.

Ποιες τεχνολογίες φέρνει το LTE-A;

http://www.tekna.no/ikbViewer/Content/787700/18%20LTE-Advanced%20Overview%20-%20Tor%20Leif%20Aarland.pdf

Further Along the Road to 4G:  An update on LTE and LTE-Advanced

http://www.home.agilent.com/upload/cmc_upload/All/Further_Along_the_Road_to_4G_an_Update_ond_LTE-Advanced_V2.pdf?cmpid=1-4254376024

[Free Tutorial]

Intelligent Transportation Systems: Advanced Communications Technologies & Applications

(https://www.comsoc.org/files/Career/free-tutorials/Intelligent.jpg)

Abstract: Intelligent Transportation Systems (ITS) based on wireless communications, the Internet, GPS, and sensor networks are emerging.  The central idea in an ITS system is to deliver useful information to all kinds of motorists, such as ordinary drivers, emergency vehicles, transit and service vehicles. The goal is to shorten driving time, make driving safer, speed law and medical assistance and others, and contribute to a better environment.

Engineers and researchers are identifying key issues to address to enable successful Intelligent Transportation Systems. This presentations provides an open discussion on recent research results on a broad range of topics relevant to ITS architecture, network support, communication-based technologies and application development.

link: https://www.comsoc.org/form/tutorial-registration-intelligent-transportation-systems-advanced-communications-technologies-a

Ιστορικά  ;)

FCC: POTS is History

The FCC gave the go ahead for a next-gen telephone network sending digitized voice and data through the internet rather than copper-based Plain Old Telephone Service and central offices.

(http://farm8.staticflickr.com/7371/12252816666_d85741432d.jpg)

AT&T and Verizon received a nod to test moving telephone services from existing circuit-switch technology to Internet protocol to see how the change may affect consumers.
The experiments would not test the new technology – it is already being used. The trials would seek to establish, among other things, how consumers welcome the change and how new technology performs in emergency situations, including in remote locations.

The IP transition tests allow companies that offer landline phone services to ultimately replace their old copper wires with newer technology like fiber or wireless.

“We cannot continue requiring service providers to invest in both old networks and new networks forever,” Commissioner Ajit Pai, a Republican, said.

More than a third of adults use cellphones as their only form of phone service, up from just 5 percent a decade ago. Federal regulations require phone companies to maintain the plain, old telephone system even as they continue building out advanced networks that imposes costs and slows investment.

Meanwhile, consumer advocates caution that moving too quickly to an IP-based phone network could leave some Americans behind.

link: http://www.dailywireless.org/2014/01/31/fcc-pots-is-history/

άλλα χρήσιμα:
[1] http://www.fcc.gov/document/fcc-oks-voluntary-experiments-testing-impact-technology-transitions
[2] http://en.wikipedia.org/wiki/Plain_old_telephone_service
[3] http://www.washingtonpost.com/blogs/the-switch/wp/2014/01/30/the-fcc-is-beta-testing-a-next-gen-telephone-network/
[4] http://www.reuters.com/article/2014/01/30/usa-fcc-iptransition-idUSL2N0L414G20140130

REGENERATIVE PAYLOADS IN SATELLITE COMMUNICATIONS

http://www.dlr.de/rd/Portaldata/28/Resources/dokumente/RA/Rodriguez.pdf

Συνοπτικές σημειώσεις από MIT για Satellite Communications!

http://ocw.mit.edu/courses/aeronautics-and-astronautics/16-851-satellite-engineering-fall-2003/lecture-notes/l21satelitecomm2_done.pdf

A guide to communication satellites:

http://www.eutelsat.com/files/contributed/news/media_library/brochures/guide-to-satellites.pdf

Tech Focus - Signal Processing in Communications

Free Access to papers on Signal Processing from recent IEEE Communications technical conferences, magazines, and journals.
(https://www.thmmy.gr/smf/index.php?action=dlattach;topic=57035.0;attach=50313)
Partial list includes:

• Signal Processing Communications Protocols
  
• Comprehensive sensing framework for signal processing in heterogeneous cellular networks
• Spectral efficiency in signal processing radios in interference limited environments
• Signal processing advances in speech recognition
• 100-Gb/s optical transport in employing digital signal processing
• An analysis of uplink base station cooperation with practical constraints
• Optimized scheduling algorithm for LTE downlink systems
• Multi-user Pre-processing in multi-antenna OFDM TDD systems with non-reciprocal transceivers
• DSP-based optical access approaches for enhancing NG-PON2 Systems

https://www.comsoc.org/form/tech-focus-registration-signal-processing-in-communications

Τηλεπικοινωνιακά νέα  :D

Vehicle-to-Vehicle Communications Tech Will Be Mandatory, say Feds

By Lucas Laursen
Posted 4 Feb 2014 | 19:41 GMT

(http://spectrum.ieee.org/img/USDepartmentofTransportationV2V-2-1391534593857.jpg)
Illustration: U.S. Department of Transportation


The National Highway Traffic Safety Administration (NHSTA) will soon propose rules for vehicle to vehicle (V2V) communications on U.S. roads, it announced yesterday. The agency is now finalizing a report on a 2012 trial with almost 3000 cars in Ann Arbor, Michigan, and will follow that report with draft rules that would "require V2V devices in new vehicles in a future year."

A car changing lanes, for example, might get a warning from its V2V system that another car is fast approaching in the driver's blind spot. NHTSA, which has been researching V2V since 2002, claims that such systems could prevent three quarters of road crashes. A public-private partnership in Europe has been testing V2V technologies since 2008, IEEE Spectrum reported at the time.

As envisioned by NHTSA, vehicles equipped with V2V would send position and speed data to one another ten times per second over an ad hoc wireless network. Onboard computers could then calculate whether nearby vehicles are a threat and alert drivers. Future protocols might incorporate information from the sort of onboard sensors that are growing more popular among carmakers, creating a road-spanning network of sensors and alerting cars to problems up or down the road. That kind of data ubiquity would help drivers avoid one another, and is a step toward more autonomy for self-driving cars.

As usual, there are tradeoffs. The agency wrote that V2V data would not identify vehicles, but added that, "vehicles would be identifiable through defined procedures only if there is a need to fix a safety problem" without defining those procedures. That implies that some sort of identifying information is in the system.

Drivers might as well accept that modern vehicles are no more capable of protecting their personal information, including location, than are mobile phones, as a Ford executive's comments made clear last month. The NHTSA also notes on its V2V website that, "Anonymous data from connected vehicles will be open to the public and can be used for a myriad of new safety, mobility and environmental applications." The paranoid will not take comfort in that: computer scientists have shown again and again that identifying individuals from anonymized data is easy.

David Friedman, the NHTSA's acting administrator, put a positive spin on his announcement, writing that future generations will remember this as the moment that, "the historical arc of transportation safety considerably changed for the better." Not the smoothest of people to people communications, but then again, this is about cars.

Source: http://spectrum.ieee.org/tech-talk/green-tech/advanced-cars/vehicle-to-vehicle-tech-will-be-mandatory-say-feds

Το LTE1800 είναι αυτό που χρησιμοποιούν οι εταιρίες που παρέχουν υπηρεσίες κινητής στην Ελλάδα (Cosmote και Vodafone).

Για περισσότερες πληροφορίες, μπορείτε να δείτε στα

[1] http://www.gsma.com/spectrum/wp-content/uploads/2012/03/lte1800mhzwhitepaper0.9.pdf
[2]https://d1dmfej9n5lgmh.cloudfront.net/gsmonline/article_attachments/attachments/33985/original/martin_ljungberg_ericsson_mwc_barcelona_2011.pdf?1353374287

Heterogeneous Networks

Anders Furuskär from Ericsson Research talks about Heterogeneous Networks, also known as HetNets. Heterogeneous networks are an attractive means of expanding mobile network.

https://www.youtube.com/watch?v=vTCYvbwmgEA

http://www.youtube.com/watch?v=vTCYvbwmgEA

Διάρκεια: 4:01

Heterogeneous Networks in LTE

by Jeanette Wannstrom, masterltefaster.com and Keith Mallinson, WiseHarbor

Effective network planning is essential to cope with the increasing number of mobile broadband data subscribers and bandwidth-intensive services competing for limited radio resources. Operators have met this challenge by increasing capacity with new radio spectrum, adding multi-antenna techniques and implementing more efficient modulation and coding schemes. However, these measures alone are insufficient in the most crowded environments and at cell edges where performance can significantly degrade. Operators are also adding small cells and tightly-integrating these with their macro networks to spread traffic loads, widely maintain performance and service quality while reusing spectrum most efficiently.

One way to expand an existing macro-network, while maintaining it as a homogeneous network, is to “densify” it by adding more sectors per eNB or deploying more macro-eNBs. However, reducing the site-to-site distance in the macro-network can only be pursued to a certain extent because finding new macro-sites becomes increasingly difficult and can be expensive, especially in city centres. An alternative is to introduce small cells through the addition of low-power base stations (eNBs, HeNBs or Relay Nodes (RNs)) or Remote Radio Heads (RRH) to existing macro-eNBs. Site acquisition is easier and cheaper with this equipment which is also correspondingly smaller.

Small cells are primarily added to increase capacity in hot spots with high user demand and to fill in areas not covered by the macro network – both outdoors and indoors. They also improve network performance and service quality by offloading from the large macro-cells. The result is a heterogeneous network with large macro-cells in combination with small cells providing increased bitrates per unit area. See Figure 1.

(http://www.3gpp.org/images/articleimages/Hetnet/fig001.jpg)


Η συνέχεια στο: http://www.3gpp.org/technologies/keywords-acronyms/1576-hetnet

LTE-A PHY Layer Overview &  Femto Design Challenges

http://sites.cttc.es/femtoschool/images/presentations/5_mariuspesavento_tudarmstadt_lteaphylayer.pdf

Και το video της παραπάνω παρουσίασης:
http://lteworld.org/video/lte-phy-layer-overview-femto-design-challenges

Telecommunications Satellites

Satellite telecommunication is the most mature of space applications. Starting 50 years ago with the launch of Telstar in 1962 and Syncom in 1963, satcom has continued to grow ever since.

At first, satellite performance was very limited. To compensate for this, very large ground stations with dish antennas more than 20 metres in diameter were required to establish links with them. The use of satellites was limited to long distance telephony and to the transport of television signals between studios.

By 1990, two out of every three intercontinental telephone calls were transmitted by telecommunication satellites. Satellites proved particularly useful for communicating with many of the countries in the less developed parts of the world.
 
New technology and different kinds of demand have changed the way communications satellites are used. More powerful satellites and the use of higher frequencies have made it possible for many people to receive direct signals from the sky. At the beginning of the 21st century, more than 100 million European homes were able to watch television programmes transmitted by satellites, either by direct reception or through cable distribution systems.

Satcom: Where space meets daily life
Today telecommunications satellites are part of our daily lives. Many everyday activities rely on telecommunication satellites that are in orbit, almost 36 000 kilometres above our heads.

Did you know that:

When you listen to the radio, it is very likely that the signal you are receiving has been distributed from the central studios by satellite?
Many newspapers and magazines are produced locally but printed centrally? The content of the paper is sent to the printing plants using satellite links.
Even when a news or sports event shown on television is taking place just a few kilometres away from the studios, it has probably been transmitted via satellite?
Most news agencies use satellites to distribute text, audio and video to their affiliates?
In many countries, access to the Internet is by satellite communication? Internet service providers often link their servers to the core of the Internet network by satellite. With the emergence of very powerful broadband satellites, users – equipped with their own broadband interactive satellite terminals – will get access to the Internet regardless of their distance from the nearest terrestrial node.

http://www.esa.int/Our_Activities/Telecommunications_Integrated_Applications/Telecommunications_satellites

LTE Radio Coverage Webinar

http://lteworld.org/video/lte-radio-coverage-webinar

5G Service On Your 4G Phone?

(http://spectrum.ieee.org/img/Artemis_pCells_in_Times_Squareb-1392792855139.jpg)

A new San Francisco-based start-up, Artemis Networks, announced today that it plans to commercialize its “pCell” technology, a novel wireless transmission scheme that could eliminate network congestion and provide faster, more reliable data connections. And the best part? It could work on your existing 4G LTE phone.

If it proves capable of scaling, pCell could radically change the way wireless networks operate, essentially replacing today’s congested cellular systems with an entirely new architecture that combines signals from multiple distributed antennas to create a tiny pocket of reception around every wireless device. Each pocket could use the full bandwidth of spectrum available to the network, making the capacity of the system “effectively unlimited,” says Steve Perlman, Artemis’s CEO.

First introduced in 2011 under the name DIDO (for distributed input, distributed output), pCell seems almost too fantastic to believe. And no doubt Artemis will have plenty of critics to pacify and kinks to smooth out before operators like Verizon or AT&T pay serious attention. But there are at least a couple reasons why the idea might have some real legs.

First, it’s an elegant solution to a persistent global problem. Wireless traffic is more than doubling each year and cellular operators are struggling to keep up with that growth. “Demand for spectrum has outpaced our ability to innovate,” says Perlman, whose past entrepreneurial ventures include the cloud-based gaming service OnLive and WebTV (now MSN TV), which he sold to Microsoft in 1997.

The reason isn’t for a lack of ideas. The wireless industry is pursuing plenty of them, including small cells, millimeter-wave spectrum, fancy interference coordination, and multiple antenna schemes such as MIMO. But Perlman thinks many of these fixes are just clever kludges for an outdated system. The real bottleneck, he argues, is the fundamental design of the cellular network. “There is no solution if you stick with cells,” he says.

What’s wrong with cells? In a word: interference. Base stations and wireless devices must carefully coordinate their transmission power and spectrum use so that they don’t jam one another’s signals. This ability to divide spectrum resources among many users has been at the heart of mobile systems pretty much since they emerged in the 1980s. It’s also the reason why data rates tend to plummet when many users try to use the same cells, such as in New York City’s Times Square.

Artemis is approaching wireless transmission in a completely new way. Basically, its pCell technology could allow each wireless device to use the full bandwidth of the network regardless of how many users join and how tightly they’re packed together. It’s as if your phone were continuously the sole user of its own personal cell. Hence the name pCell.

To understand how such a system would work, let’s start with the basic set-up. To deploy the technology, an operator would first need a cloud-based data center—a rack or many racks of connected servers that would do all the heavy computation for the system. The operator would then need to install radio antennas where its customers are located, such as in homes, businesses, and city streets. Although these access points might look like small cells (Artemis’s, pictured below, are about the size of a hat box), they’re unlike ordinary base stations. “They’re dumb devices,” Perlman says, serving merely as waypoints for relaying and deciphering signals. Each one could be placed anywhere that’s convenient and would link back to the data center through a fiber or wireless line-of-sight Internet connection.

(http://spectrum.ieee.org/img/Artemis_pWave_Sky-1392792585452.jpg)

Now suppose that your phone wants to connect with this pCell network. It would simply send out an access request as it normally does. And all of the “dumb” antennas in your vicinity—let’s say there are 10 of them—would pick up those signals and relay them to the data center.

That’s where things get interesting. Say, for example, you play a YouTube video. The pCell data center would request the video from Google’s servers, and then stream it to your phone through those 10 antennas. But here’s the key innovation: No one antenna would send the complete stream or even part of the stream. Instead, the data center would use the positions of the antennas and the channel characteristics of the system, such as multipath and fading, to calculate 10 unique waveforms, each transmitted by a different antenna. Although illegible when they leave the antennas, these waveforms would add up to the desired signal at your phone, exploiting interference rather than trying to avoid it.

And as you move about, and as other devices connect to and drop off the network, the data center would continuously recalculate new waveforms so that each device receives the correct aggregate signal. “There’s no handoffs and one has to take turns,” Perlman says. “You could literally light up a whole city using all the same spectrum.”

If pCell technology does take off in the next few years, it will likely be because it’s compatible with 4G LTE phones. It does this by simulating LTE base stations in software. The data center would use these virtual radios to inform its waveform calculations, essentially tricking an LTE phone into believing it’s connected to a physical base station. “Your phone thinks its the only phone in the cell and is sitting right next to the tower,” Perlman says. The same technique could also work for other wireless standards, such as 3G and Wi-Fi, he says.

So will operators adopt pCell? It’s unlikely that LTE carriers would replace their networks any time soon, even if Artemis’s technology proves to be the “sea change” Perelman believes it is. But its compatibility with LTE changes the game. For instance, operators could deploy pCell antennas in congested hot spots such as airports, sports stadiums, and city centers—places where they’re already investing in new infrastructure. Users could roam seamlessly between the two networks without having to buy new phones or switch service plans.

Artemis says it plans to license pCell to wireless carriers and Internet service providers. The company is now beginning large-scale trials in San Francisco and expects the technology will be ready for commercial rollouts by the end of 2014. It will be fascinating to see how its ambitions pan out.

source: http://spectrum.ieee.org/tech-talk/telecom/wireless/5g-service-on-your-4g-phone/?utm_source=techalert&utm_medium=email&utm_campaign=022014

LTE-A R.10 tutorial video ~6 min!


http://www.mastertelecomfaster.com/lte10/overview.php

[book] Fundamentals of Wireless Communication

Excerpt: The writing of this book was prompted by two main developments in wireless communication in the past decade. First is the huge surge of research activities in physical-layer wireless communication theory. While this has been a subject of study since the sixties, recent developments such as opportunistic and multiple input multiple output (MIMO) communication techniques have brought completely new perspectives on how to communicate over wireless channels. Second is the rapid evolution of wireless systems, particularly cellular networks, which embody communication concepts of increasing sophistication. This evolution started with second-generation digital standards, particularly the IS-95 Code Division Multiple Access standard, continuing to more recent third-generation systems focusing on data applications. This book aims to present modern wireless communication concepts in a coherent and unified manner and to illustrate the concepts in the broader context of the wireless systems on which they have been applied.

link: http://www.eecs.berkeley.edu/~dtse/Chapters_PDF/

DVB S2

http://www.advantechwireless.com/wp-content/uploads/DVB-S2-theory.pdf

Αποτελέσματα Εξεταστικής Φεβρουαρίου 2014 στο eThmmy.


Όποιος θέλει μπορεί να έρθει να δει το γραπτό του τη Δευτέρα 11.00 πμ

Μία ακόμη ωραία παρουσίαση για το LTE-A:

http://www.tekna.no/ikbViewer/Content/787700/18%20LTE-Advanced..

An excellent webinar presented by Rohde & Schwarz on the basics of Long Term Evolution (LTE) a year ago.

Part 01 - LTE Introduction

Part 02 - LTE Parameters and Downlink Modulation

Part 03 - OFDMA and Downlink Frame Structure Details

Part 04 - SC-FDMA and LTE Uplink

Part 05 - Network and Protocol Architecture

Part 06 - Channel Mapping and UE Categories

Part 07 - Initial Cell Search and Cell Selection

Part 08 - System Information

Part 09 - Random Access Procedures and EPS Bearer Setup

Part 10 - Uplink Channels and Signals

Part 11 - LTE Mobility and MIMO Introduction

Part 12 - Downlink and Uplink MIMO in LTE

Part 13 - eNodeB and UE Performance Requirements

Part 14 - UE Certification and Field Trials



link: http://lteworld.org/presentation/long-term-evolution-lte-basics

LTE-A and Beyond

http://www.rsm.govt.nz/cms/pdf-library/policy-and-planning/events/presentations-at-seminar-for-future-wireless-technologies-4-nov-2010/LTE_A_and_Beyond_Huawei.pdf

5G: A Technology Vision

5G wireless networks will support 1,000-fold gains in capacity, connections for at least 100 billion devices, and a 10 Gb/s individual user experience capable of extremely low latency and response times. Deployment of these networks will emerge between 2020 and 2030. 5G radio access will be built upon both new radio access technologies (RAT) and evolved existing wireless technologies (LTE, HSPA, GSM and WiFi). Breakthroughs in wireless network innovation will also drive economic and societal growth in entirely new ways. 5G will realize networks capable of providing zero distance connectivity between people and connected machines.

Gearing up for a new era in Earth observation

Aiming for launch at the end of March, the first satellite built specifically for Europe’s ambitious Copernicus environmental monitoring programme is now in the last stages of testing before being shipped to French Guiana for liftoff.

Rising to the challenges of global change and the need to manage the environment more effectively, Copernicus offers a set of key information services for a multitude of environmental and civil security applications.

(http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/01/sentinel-1_testing_in_cannes/13494188-1-eng-GB/Sentinel-1_testing_in_Cannes_small.jpg)

The provision of timely and accurate data is central to this innovative global monitoring programme so ESA is developing six families of Sentinel satellite missions. Each carries state-of-the-art technologies to supply a stream of complementary imagery and data tailored to the needs of Copernicus.

 
Stowed for testing
The data from the Sentinels are open to users worldwide and free of charge.

Sentinel-1, the first in the family of Copernicus satellites, marks a new paradigm in Earth observation and the start of a new era that sees the shift from demonstration and research to operational missions set to support users for decades to come.

This new satellite will be used to care for many aspects of our environment, from detecting and tracking oil spills and mapping sea ice to monitoring movement in land surfaces and mapping changes in the way land is used.

It will also play a crucial role in providing timely information to help respond to natural disasters and help humanitarian efforts.

(http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/01/sentinel-1_radar_vision/13494392-1-eng-GB/Sentinel-1_radar_vision_medium.jpg)
 
Radar vision
As a radar mission, it can image Earth’s surface through cloud and rain and during the day and night.

This all-weather capability, for example, makes it ideal for monitoring floods, which are typically accompanied by cloud cover, and for monitoring the polar regions, which are shrouded in darkness during the winter months.

Sentinel-1 also carries a laser to transmit data to the European Data Relay System, EDRS, for fast delivery to Earth. EDRS is a network of ground stations and multiple satellites in geostationary orbit designed for relaying data.

The Sentinel-1 mission, as with Sentinel-2 and Sentinel-3, is a constellation of two identical satellites to provide optimal global coverage.


 
Simulated Sentinel-1 image
Sentinel-1A is now nearing its time to be launched into orbit. Its sister satellite, Sentinel-1B, will follow in 2015.  

This first Sentinel spent the last months being put through its paces first at Thales Alenia Space in Rome Italy, and now in Cannes, France.

The latest round of tests has included carefully determining its mass and centre of gravity as well as vibration, acoustic and launcher separation shock tests.

(http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/01/simulated_sentinel-1_image/13494423-1-eng-GB/Simulated_Sentinel-1_image_small.jpg)
 
Sentinel-1 under mechanical tests
Having accurate knowledge of the satellite’s total mass and centre of gravity, for example, is vital for manoeuvring it in orbit.

Simulating the vibrations and noise of launch and the shock of the separation from the rocket ensure that the satellite and its various components are able to withstand this all-important step of getting this carefully engineered craft safely into orbit around Earth.

(http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/01/sentinel-1_under_mechanical_tests/13494471-1-eng-GB/Sentinel-1_under_mechanical_tests_small.jpg)

Over the next weeks, engineers at Thales Alenia Space will be completing the few remaining tests, which include checking that the solar panels and radar deploy correctly, before packing it up for shipment to Europe’s spaceport in Kourou in French Guiana.

Shipment is currently planned for 21 February.


Πηγή: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Gearing_up_for_a_new_era_in_Earth_observation

Webinar

M2M Managing the Risks of Today
Some of the same elements that have given rise to the M2M industry boom have also enabled a variety of new security threats. In this webinar we will discuss the latest security solutions in M2M. Case studies and trends for the future in M2M Security will be presented as well.


https://mwjournalevents.webex.com/mw0401l/mywebex/default.do?nomenu=true&siteurl=mwjournalevents&service=6&rnd=0.3320620266856623&main_url=https%3A%2F%2Fmwjournalevents.webex.com%2Fec0701l%2Feventcenter%2Fevent%2FeventAction.do%3FtheAction%3Ddetail%26confViewID%3D1004650487%26%26%26%26siteurl%3Dmwjournalevents

LTE and the Evolution to LTE-Advanced Fundamentals

http://www.youtube.com/watch?v=-62ol7zW9Zc

LTE-A PHY Layer Overview & Femto Design Challenges

http://www.youtube.com/watch?v=JyKJ4_CybiE

CERN and ESA sign cooperation agreement

At a ceremony today at Geneva airport, CERN and ESA signed a framework agreement for future cooperation on research and technology in areas of mutual interest. Future areas may include the development and characterization of innovative materials for applications in extreme conditions and for cutting-edge scientific performances, the development of new micro-technologies to be applied in miniaturized distributed sensor systems and the development and testing of high-performance detectors for high-energy physics experiments and space payloads.
“CERN and ESA have common roots and share a long history of pioneering research work in their respective fields,” said CERN Director General Rolf Heuer. “This new cooperation agreement will foster synergies between the expertise, know-how and facilities available in the two Organizations.”
This year is CERN’s 60th anniversary and ESA’s 50th, making the signature an opportunity to celebrate the memory of a scientist who was a founding father of both organizations: the Italian, Edoardo Amaldi (1908 –1989).
Amaldi had an unshakeable belief in the open nature of science and the need for international cooperation. After participating in the creation of CERN during the 1950s, he became Secretary General of the provisional organization. Then, in 1958 when CERN was firmly established, he joined forces with French physicist Pierre Auger to urge European governments to set up a European organisation for space research, based on the CERN model. Their vision led to the founding of the European Space Research Organisation (ESRO), which later became ESA.
During the ceremony, ESA Director General Jean-Jacques Dordain presented Heuer with copies of letters by Amaldi in which he lays out his concern for peace, and the role science should play in fostering it. These letters were flown aboard ESA’s Automated Transfer Vehicle 3 – a spacecraft named in Amaldi’s honour.  The ceremony took place in the presence of members of Amaldi’s family, along with Research Ministers and State Secretaries from Belgium, France, Italy and Switzerland.
“ESA and CERN are the daughters of visionaries like Amaldi,” said Dordain, “testimony that, when we share the same challenging objectives and join forces, Europe is at the leading edge of progress, innovation and growth.”

Source: http://home.web.cern.ch/about/updates/2014/03/cern-and-esa-sign-cooperation-agreement

The Story of an 802.11ac Network

https://www.youtube.com/watch?v=XoC36DEUbf8&list=PL0C95AFFE4ABE88B3

Arianespace—Sentinel-1A Getting Final Checkout (Launch Preparations)

[SatNews] Arianespace's seventh Soyuz to be launched from French Guiana is now undergoing final checkout for its April 3 liftoff following installation of the mission's satellite passenger—Sentinel-1A—atop this medium-lift vehicle.

Sentinel-1A's mating with Soyuz occurred yesterday, after the workhorse Russian-built vehicle rolled out to the launch pad in the Spaceport's northwestern sector. The satellite was fitted as part of an integrated "upper composite," consisting of Sentinel-1A, the Fregat upper stage that will place it into orbit, and the Soyuz ST fairing. The activity occurred inside the 53-meter-tall mobile gantry that provides a protected environment for the vertical payload installation.  This is one of the main differences in launcher processing at the Spaceport compared to the horizontal processing of vehicles on Soyuz launch sites at the Baikonur Cosmodrome in Kazakhstan and Plesetsk Cosmodrome in Russia.

The upcoming launch—designated Flight VS07 in Arianespace's numbering system— is scheduled at precisely 6:02:26 p.m. local time in French Guiana, on Thursday, with the mission lasting 23 minutes to Sun-synchronous orbit. Sentinel-1A is to deliver essential data for Copernicus, a program of the European Commission in partnership with the European Space Agency - which will create a sustainable European satellite network to collect and evaluate environmental data for civil safety and humanitarian purposes. The spacecraft was developed in an industrial consortium led by Thales Alenia Space as prime contractor, with Airbus Defence and Space responsible for the C-SAR synthetic aperture radar payload.

Follow Arianespace's launch activity at http://www.arianespace.com/.

(http://www.satnews.com/images_upload/91753626/Aspace_Sentinel-1A_fairing.jpg)

Statement by Neelie Kroes on EP votes to end roaming charges

http://ec.europa.eu/avservices/video/player.cfm?ref=I088198

(https://www.comsoc.org/files/Career/free-tutorials/4G5G.jpg)

This presentation covers the advancement of wireless communications and networking technology for current generation as well as evolution of future generations.

Topics enable a wireless ecosystem, from service providers seeking answers on delivering services and meeting demand, to device manufacturers and developers seeking to understand the applications in LTE, LTE-A, 4G/5G, etc. Wireless access demands have given rise to wireless networks that significantly rely on satellite communication to enable rural and remote wireless connectivity via satellite backhaul. This trend presents many opportunities and challenges for capacity improvement and coexistence of various technological elements.

Free access compliments of: GL Communications

https://www.comsoc.org/form/tutorial-registration-next-generation-4g5g-cellular-networking

Heterogeneous networks by Ericsson

http://www.ericsson.com/res/docs/whitepapers/WP-Heterogeneous-Networks.pdf

Tutorial on  Small Cell/HetNet Deploymen

http://www.ieee-globecom.org/2012/downloads/t1/1SmallCellTutorialGlobecom12Jie_v1b.pdf

LTE: The Future of Mobile Data
by Steven Hartley, Senior Analyst, Ovum, & Julien Grivolas, Principal Analyst, Ovum

Long Term Evolution (LTE), a new generation of mobile network technology, promises to revolutionize the use of data services on the move. Over the past year, it has gained unparalleled support from mobile operators around the world, particularly in North America. Its introduction is now inevitable, despite the major investment needed.

An Overview
LTE is a wireless technology often discussed alongside its more mature alternative, WiMAX, in relation to the evolution of mobile telecom networks to “4G.”* Both LTE and WiMAX technologies can deliver wireless data connectivity that is able to compete with fixed-line broadband services provided by DSL or cable. LTE’s proponents state that it may allow customers to drop their fixed-line broadband connections altogether.

LTE’s primary objective is to enable operators to better and more cost-effectively transport the rapidly growing volume of mobile IP data traffic on their networks. This mobile data traffic is growing exponentially, while the service revenues paid by end users are either flat or falling due to intense competition. This disconnection between income and costs is threatening to undermine the positive revenue-generating potential of mobile data services for operators.

(http://www.forbescustom.com/Images/Telecom_LTE_table1.jpg)

Therefore, LTE offers a long-term route to financial security. Nonetheless, migrating to LTE does require significant investment from mobile operators, and not just in upgrading base stations. For example, operators’ core networks, which carry the consolidated traffic from all base stations, will also need to evolve. Operators will also have to deploy SAE/EPC (System Architecture Evolution/Evolved Packet Core) network elements in parallel with LTE.

LTE technical specifications are defined by the 3GPP (3rd-Generation Partnership Project). The 3GPP’s role is important because it provides the technology with an enormous addressable market. In 2008, 89% of mobile connections worldwide, including those from AT&T and T-Mobile in the U.S., used one of the standards defined by the 3GPP. In addition, in an unprecedented move in the industry, many operators are shifting away from rival technologies and converging on LTE. For example, several CDMA operators, including Verizon Wireless and MetroPCS in the U.S. or Bell and TELUS in Canada, have stated publicly that they will migrate to LTE. LTE offers the next stage in the evolution of the networks on which these users depend for mobile connectivity. Such a large addressable market ensures:

maximum equipment vendor focus;
a wide range of devices;
economies of scale for operators and end users buying equipment; and
support for international roaming.

*Technically speaking, “4G“ refers to technology defined by the International Telecoms Union (ITU) as IMT-Advanced. For LTE, this refers to the next step in the evolutionary process, LTE Advanced, while for WiMAX this actually refers to 802.16m, the successor of mobile WiMAX.

The Market for LTE Services
LTE gained significant momentum as the dominant next-generation mobile access technology throughout 2008. Commercial LTE launches will initially appear on a small scale in Japan, the U.S. and Sweden in 2010, with larger players in Western Europe following in 2011 to 2012.

The ramp-up in LTE deployments can be seen in the massive year-on-year connections growth forecast for both 2013 (219%) and 2014 (175%). We expect to see 109 million LTE connections worldwide by 2014, as shown in Figure 1. We estimate that the number of LTE connections will almost equal those for mobile WiMAX in 2013 and will be double the number of mobile WiMAX connections in 2014. Clearly, the window of opportunity for mobile WiMAX is closing rapidly with such widespread support for LTE.

However, challenges remain as to the business case for LTE at an individual operator level. In the current economic climate, investors will frown upon the significant investments required to deploy LTE if sufficient return on that investment cannot be proven. There are market circumstances that favor a more aggressive deployment, such as evolving to LTE from CDMA, particularly if faced with an operator deploying HSPA+. But operators need to take a very hard look at the business case, especially when the evolution of HSPA offers a potential alternative on existing infrastructure. HSPA will remain the dominant data-optimized network technology, accounting for 79% of high-speed data connections in 2014.

(http://www.forbescustom.com/Images/Telecom_LTE_chart1.jpg)

Key Suppliers of Mobile LTE Network Equipment
All the major mobile infrastructure vendors consider LTE the strategic technology for future mobile broadband communications and therefore are actively targeting this business opportunity. However, differences remain in the way they approach this opportunity due to several parameters:

Current market position in legacy technologies (e.g. CDMA, GSM/UMTS/HSPA and TD-SCDMA)
Ability to evolve the entire network or one part of the network
Ease of migrating from legacy products
The vendor’s R&D capabilities to enable customized solutions for specific operator needs
Vendor financial health to support operators throughout the whole migration, which is likely to span several years
The increased maturity of the technology is reflected in the announcement of the first contracts between LTE and SAE. However, the industry must avoid raising expectations too far. It did this with the expensive deployment of 3G, which is only now reaping dividends, thanks to HSPA—and not the oversold UMTS. Many issues still need to be addressed.

Device Development Lagging Behind Networks
Commercial launches of LTE networks are expected to start in 2010. However, the first devices will be data-only external modem devices such as data cards and USB modems. For operators, data-only devices are more significant for LTE compared to previous network rollouts, since voice services are now provided by legacy technologies.

Initial LTE handsets will follow after about a year, but are still most likely to rely on the existing network for voice calls and therefore only use LTE for data. Handsets that natively support voice over the LTE network will take approximately one year longer to appear on the market. In the meantime, handsets will need to support multiple mobile technologies to support voice services.

This highlights one of the primary obstacles to device development: Initial chipsets for LTE handsets will all need to be multimode. This means they must support 3G services alongside LTE, so that users can still receive a service even if they move to a location outside of LTE coverage, and to ensure that the handover between two technologies during a voice call or data session is seamless.

The technical complexity of the new technology means that LTE devices will be more expensive than their 3G counterparts. Costs will start to fall only once a volume market has been established. A premium associated with LTE devices will exist for some time due to the increased memory and processor requirements needed to process the volume of data enabled by LTE. Nonetheless, LTE will encourage smartphone adoption as service providers look to drive up data usage and offer superior browsing experiences.


Nokia Siemens Networks
An Interview with Sue Spradley, Head of Nokia Siemens Networks for North America


Broadband is everywhere. The Internet already plays a pivotal role in our daily lives, and it will become even more pervasive as the Internet goes mobile. Nokia Siemens Networks (NSN) has been at the forefront of LTE or 4G wireless technology development for many years. The company is the first network provider in the world to complete a number of LTE milestones, including the world’s first LTE call using commercial hardware and software. With its global scope and scale and deep understanding of network operation requirements, Nokia Siemens Networks is continually devising innovative ways to use this technology strategically to address its customers’ key business challenges and lead industry growth.

What do you see as the main trends in the mobile industry? How can LTE help in addressing the associated network issues?
Over the past few years, we have seen explosive data traffic growth as millions of services and billions of devices come online. As more and more people use mobile data for work, entertainment and social networking, service providers have to find ways to optimize their assets, like spectrum, and do so as efficiently as possible. This is where LTE comes in.

Our opportunity is to help operators discover new ways to leverage their networks to give their customers a unique experience that differentiates them. NSN’s vision of a “Network of One” puts the customer at the center of the network and allows service providers to create an environment that delivers a personalized experience easily and efficiently. Our Subscriber Data Management (SDM) solution is a game changer for our company. It plays a critical role in helping service providers tailor the user experience for each subscriber.

What is your view on LTE market development in the U.S. and globally?
Being involved in the LTE deployment for the provider NTT DoCoMo in Japan, we see Japan, along with the U.S., aggressively leading the world toward commercial LTE services. These operators want to move quickly. Knowing that companies like Verizon and AT&T are leading the way to LTE in the U.S., we have established our Next-Generation Lab and LTE Center of Competence in Dallas so that we have R&D, interoperability testing and much more in our own backyard.

What specific challenges will operators face when migrating to LTE?
It is critical to understand that LTE migration means an end-to-end evolution. People tend to only think about radio access, but it is really the tip of the iceberg of what is involved in 4G migration. For example, core network and backhaul also have to be considered. Everything has to be 100% IP, which means that wireless operators need to be, or at least need network partners who are, well versed in IP technology and its characteristics. We’re basically seeing the worlds of telecom and IT fusing together, so in some sense, many companies are entering uncharted territory, which can be an exciting adventure.

What is Nokia Siemens Networks’ key value proposition to support operators migrating to LTE?
In North America, Nokia Siemens Networks’ unique value proposition is providing a network advantage that makes the network a catalyst for communication service provider innovation. We do this in many ways, but key differentiators for us are the core networks and SDM solutions that we’ve delivered to the majority of tier one operators in the U.S. and Canada. This is actually the most critical part of the transition to get right, and it’s what we do best. We are leading the way in LTE as we help service providers create the best user experience for their customers.

Πηγή: http://www.forbescustom.com/TelecomPgs/LTEP1.html
 

Radio Wrestlers Fight It Out at the DARPA Spectrum Challenge

Clash of the software-defined radio algorithms leaves two winners

(http://spectrum.ieee.org/img/04NWDarpaSpectrumChallengeOrbit-clean-300-1397071798183.jpg)

Photo: Darpa
Flying Bits: The 465 square-meter, 400-node ORBIT radio grid facility at Rutgers University, in New Jersey, hosted DARPA Spectrum Challenge software defined radio algorithms in head-to-head competitions.
The words engineering and sports aren’t usually used in the same sentence, and the two activities usually don’t happen in the same room. But they were, and they did, last week at the DARPA Spectrum Challenge, held at the Defense Advanced Research Projects Agency headquarters in Arlington, Va.

The goal of the contest, the first ever DARPA challenge on the use of spectrum, was to demonstrate how a software-defined radio can use a given communication channel in the presence of other users and interfering signals. Over the course of two days, normally taciturn techies oohed, aahed, and cheered as 18 teams competed in a series of head-to-head matches to see who had the best algorithms.

A nearly yearlong process winnowed an initial field of 90 teams down to the 18 that competed last month. While most of the teams were composed of academics, there were also amateur hobbyists, including a medical doctor whose second love is electronics and a 28-year-old contract programmer with no formal education beyond high school.

For more: http://spectrum.ieee.org/telecom/wireless/radio-wrestlers-fight-it-out-at-the-darpa-spectrum-challenge

A Survey on Device-to-Device Communication in Cellular Networks

http://arxiv.org/pdf/1310.0720v3.pdf

The second phase of LTE-A

https://www.google.gr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0CJIBEBYwCA&url=http%3A%2F%2Fwww.huawei.com%2Filink%2Fen%2Fdownload%2FHW_259010&ei=bXhPU_uPAsrPtAaT-YBg&usg=AFQjCNGqWt91brhtxabWq_-Zqb0QJqOTew&sig2=JNkzaW3ICzppRIs7f13Gaw&bvm=bv.64764171,d.Yms

Design Aspects of Network Assisted Device-to-Device Communications

http://www1.ericsson.com/res/docs/2012/design-aspects-of-network-assisted-device-to-device-communications.pdf

Fundamentals of Satellite Communications

http://www.ieee.li/pdf/viewgraphs/fundamentals_satellite_communication_part_1.pdf
http://www.ieee.li/pdf/viewgraphs/fundamentals_satellite_communication_part_2.pdf
http://www.ieee.li/pdf/viewgraphs/fundamentals_satellite_communication_part_3.pdf
http://www.ieee.li/pdf/viewgraphs/fundamentals_satellite_communication_part_4.pdf

SATELLITE COMMUNICATION – AN INTRODUCTION

http://www.mu.ac.in/myweb_test/Satelight%20Comm..pdf

Mobile Communications: Satellite Systems

http://paginas.fe.up.pt/~mleitao/CMOV/Teoricas/CMOV_SAT.pdf

How Japan Plans to Build an Orbital Solar Farm

JAXA wants to make the sci-fi idea of space-based solar power a reality

(http://spectrum.ieee.org/img/05SolarSpaceOpener-1397829304740.jpg)
Here Comes the Sun: Mirrors in orbit would reflect sunlight onto huge solar panels, and the resulting power would be beamed down to Earth.

Imagine looking out over Tokyo Bay from high above and seeing a man-made island in the harbor, 3 kilometers long. A massive net is stretched over the island and studded with 5 billion tiny rectifying antennas, which convert microwave energy into DC electricity. Also on the island is a substation that sends that electricity coursing through a submarine cable to Tokyo, to help keep the factories of the Keihin industrial zone humming and the neon lights of Shibuya shining bright.

But you can’t even see the most interesting part. Several giant solar collectors in geosynchronous orbit are beaming microwaves down to the island from 36 000 km above Earth.

It’s been the subject of many previous studies and the stuff of sci-fi for decades, but space-based solar power could at last become a reality—and within 25 years, according to a proposal from researchers at the Japan Aerospace Exploration Agency (JAXA). The agency, which leads the world in research on space-based solar power systems, now has a technology road map that suggests a series of ground and orbital demonstrations leading to the development in the 2030s of a 1-gigawatt commercial system—about the same output as a typical nuclear power plant.

It’s an ambitious plan, to be sure. But a combination of technical and social factors is giving it currency, especially in Japan. On the technical front, recent advances in wireless power transmission allow moving antennas to coordinate in order to send a precise beam across vast distances. At the same time, heightened public concerns about the climatic effects of greenhouse gases produced by the burning of fossil fuels are prompting a look at alternatives. Renewable energy technologies to harvest the sun and the wind are constantly improving, but large-scale solar and wind farms occupy huge swaths of land, and they provide only intermittent power. Space-based solar collectors in geosynchronous orbit, on the other hand, could generate power nearly 24 hours a day. Japan has a particular interest in finding a practical clean energy source: The accident at the Fukushima Daiichi nuclear power plant prompted an exhaustive and systematic search for alternatives, yet Japan lacks both fossil fuel resources and empty land suitable for renewable power installations.

Soon after we humans invented silicon-based photovoltaic cells to convert sunlight directly into electricity, more than 60 years ago, we realized that space would be the best place to perform that conversion. The concept was first proposed formally in 1968 by the American aerospace engineer Peter Glaser. In a seminal paper, he acknowledged the challenges of constructing, launching, and operating these satellites but argued that improved photovoltaics and easier access to space would soon make them achievable. In the 1970s, NASA and the U.S. Department of Energy carried out serious studies on space-based solar power, and over the decades since, various types of solar power satellites (SPSs) have been proposed. No such satellites have been orbited yet because of concerns regarding costs and technical feasibility. The relevant technologies have made great strides in recent years, however. It’s time to take another look at space-based solar power.

A commercial SPS capable of producing 1 GW would be a magnificent structure weighing more than 10 000 metric tons and measuring several kilometers across. To complete and operate an electricity system based on such satellites, we would have to demonstrate mastery of six different disciplines: wireless power transmission, space transportation, construction of large structures in orbit, satellite attitude and orbit control, power generation, and power management. Of those six challenges, it’s the wireless power transmission that remains the most daunting. So that’s where JAXA has focused its research.

(http://spectrum.ieee.org/img/how-to-beam-clean-720-1398188152346.jpg)

Wireless power transmission has been the subject of investigation since Nikola Tesla’s experiments at the end of the 19th century. Tesla famously began building a 57-meter tower on New York’s Long Island in 1901, hoping to use it to beam power to such targets as moving airships, but his funding was canceled before he could realize his dream.

To send power over distances measured in millimeters or centimeters—for example, to charge an electric toothbrush from its base or an electric vehicle from a roadway—electromagnetic induction works fine. But transmitting power over longer distances can be accomplished efficiently only by converting electricity into either a laser or a microwave beam.

The laser method’s main advantages and disadvantages both relate to its short wavelength, which would be around 1 micrometer for this application. Such wavelengths can be transmitted and received by relatively small components: The transmitting optics in space would measure about 1 meter for a 1-GW installation, and the receiving station on the ground would be several hundred meters long. However, the short-wavelength laser would often be blocked by the atmosphere; water molecules in clouds would absorb or scatter the laser beam, as they do sunlight. No one wants a space-based solar power system that works only when the sky is clear.

But microwaves—for example, ones with wavelengths between 5 and 10 centimeters—would have no such problems in transmission. Microwaves also have an efficiency advantage for a space-based solar power system, where power must be converted twice: first from DC power to microwaves aboard the satellite, then from microwaves to DC power on the ground. In lab conditions, researchers have achieved about 80 percent efficiency in that power conversion on both ends. Electronics companies are now striving to achieve such rates in commercially available components, such as in power amplifiers based on gallium nitride semiconductors, which could be used in the microwave transmitters.

In their pursuit of an optimal design for the satellite, JAXA researchers are working on two different concepts. In the more basic one, a huge square panel (measuring 2 km per side) would be covered with photovoltaic elements on its top surface and transmission antennas on its bottom. This panel would be suspended by 10-km-long tether wires from a small bus, which would house the satellite’s controls and communication systems.

Using a technique called gravity gradient stabilization, the bus would act as a counterweight to the huge panel. The panel, which would be closer to Earth, would experience more gravitational pull down toward the planet and less centrifugal force away from it, while the bus would be tugged upward by the opposite effects. This balance of forces would keep the satellite in a stable orbit, so it wouldn’t need any active attitude-control system, saving millions of dollars in fuel costs.

The problem with this basic SPS configuration is its inconstant rate of power generation. Because the photovoltaic panel’s orientation is fixed, the amount of sunlight that hits it varies greatly as the geosynchronous satellite and Earth spin.

So JAXA has come up with a more advanced SPS concept that solves the solar collection problem by employing two huge reflective mirrors. These would be positioned so that between the two of them, they would direct light onto two photovoltaic panels 24 hours a day. The two mirrors would be free flying, not tethered to the solar panels or the separate transmission unit, which means that we would have to master a sophisticated kind of formation flying to implement this system. Space agencies have some experience with formation flying, most notably in the docking maneuvers performed at the International Space Station, but coordinating a formation flight involving kilometer-scale structures is a big step from today’s docking procedures.

We would also have to make several other breakthroughs before this advanced type of SPS could be built. We’d need very light materials for the mirror structures to allow for the formation flight, as well as extremely high-voltage power transmission cables that could channel the power from the solar panels to the transmission unit with minimal resistive losses. Such technologies would take years to develop, so if one or more nations do embark on a long-term project to exploit space-based solar power, they may employ a two-phase program that begins with the basic model while researchers work on the technologies that will allow for next-generation systems.

To generate the microwaves, researchers have proposed vacuum tubes such as magnetrons, klystrons, or traveling wave tubes, because their power conversion efficiency is reasonably high—typically 70 percent or higher—and they’re relatively inexpensive. Semiconductor amplifiers are getting better all the time, however; their efficiencies are going up, and their costs are coming down. Cost is important here because a 1-GW commercial SPS would have to include at least 100 million 10-watt semiconductor amplifiers.

To choose a microwave frequency for transmission, we have to weigh several factors. Low-frequency microwaves penetrate the atmosphere well, but they require very large antennas, which would make construction and maintenance more complicated. Frequencies in the range of 1 to 10 gigahertz offer the best compromise between antenna size and atmospheric attenuation. Within this range, 2.45 and 5.8 GHz are the potential candidates because they are in the bands set aside for industrial, scientific, and medical uses. Of these, 5.8 GHz seems particularly desirable because the transmitting antennas can be smaller.

Making a powerful beam of microwaves is important, of course, but the next step is a lot trickier: aiming the beam precisely so that it travels the 36 000 km to hit the rectifying antennas spot on.

Consider that the microwave transmission system would be composed of a number of antenna panels, each measuring perhaps 5 meters long, that would be covered in tiny antennas: In total, more than 1 billion antennas would likely be installed on a single SPS. Coordinating the microwaves generated by this vast swarm of antennas won’t be easy. To produce a single, precisely focused beam, the phases of the microwaves sent from all the antenna panels must be synchronized. That would be hard to manage, as these panels would move relative to each other.

This challenge of precisely directing a beam from a moving source is unique and hasn’t been solved by existing communication technologies. The beam must have very little divergence to prevent it from spreading out over too large an area. To send power at the 5.8-GHz frequency to a rectifying antenna, or rectenna, with a diameter of 3 km, the divergence must be limited to 100 microradians and the beam must have a pointing accuracy of 10 µrad.

JAXA’s solution involves a pilot signal that would be sent from the rectenna on the ground. As each individual antenna panel on the satellite received the pilot signal, it would calculate the necessary phases for its microwaves and adjust accordingly. The sum of all these adjustments is a tight beam that would zing down through the atmosphere to hit the rectenna. Such phase-adjusting technologies, known as retrodirective systems, have been used in small-scale antenna arrays in space, but additional work would be needed before they could coordinate several kilometers of orbital transmitters.

Once the beam reaches the receiving site, the rest of the process would be relatively easy. Arrays of rectennas would convert the microwave power to DC power with an efficiency greater than 80 percent. Then the DC power would be converted to AC and fed into the electrical grid.

When laypeople hear these orbital solar farms described, they often ask if it would be safe to send a powerful beam of microwaves down to Earth. Wouldn’t it cook whatever’s in its path, like food in a microwave oven? Some people have a grisly mental image of roasted seagulls dropping from the sky. In fact, the beam wouldn’t even be intense enough to heat your coffee. In the center of the beam in a commercial SPS system, the power density would be 1 kilowatt per square meter, which is about equal to the intensity of sunlight. As the regulatory limit for sustained human exposure to microwaves is typically set at 10 watts per square meter, however, the rectenna site would have to be a restricted area, and maintenance workers who enter that zone would have to take simple precautions, such as donning protective clothing. But the land outside the rectenna site would be perfectly safe. At a distance of 2 km from its center, the beam’s power density will have already dropped below the regulatory threshold.

In 2008, on a mountaintop on Hawaii’s main island, a rectenna received a beam of microwaves sent from the slopes of a volcano on the island of Maui, about 150 km away. That demonstration project, led by former NASA physicist John Mankins and recorded for a show on the Discovery Channel, was modest in its ambitions: Only 20 W of power were generated by the solar panels on Maui and beamed across the ocean. This setup was far from ideal because the microwaves’ phases were disturbed during this horizontal transmission through the dense atmosphere. Most of the power was lost in transmission, and less than a microwatt was received on the Big Island. But the experiment did demonstrate the general principle to an admiring public. And it’s worth remembering that in a space-based system, the microwaves would pass through dense atmosphere only for the last few kilometers of their journey.

In Japan, we are now planning a series of demonstrations for the next few years. By the end of this year, researchers expect to perform a ground experiment in which a beam of hundreds of watts will be transmitted over about 50 meters. This project, funded by JAXA and Japan Space Systems, will be the world’s first demonstration of high-power and long-range microwave transmission with the critical addition of retrodirective beam control. The microwave transmitter consists of four individual panels that can move in relation to one another in order to simulate antenna motion in orbit. Each panel, measuring 0.6 meter by 0.6 meter, contains hundreds of tiny transmitting antennas and receiving antennas to detect the pilot signal, as well as phase controllers and power management systems. Each panel will transmit 400 W, so that the total beam will carry 1.6 kW; in this early-stage experiment, we expect the rectenna to have a power output of 350 W.

Next, JAXA researchers hope to conduct the first microwave power transmission experiment in space, sending several kilowatts from low Earth orbit to the ground. This step, proposed for 2018, should test out the hardware: We hope to demonstrate microwave beam control, evaluate the system’s overall efficiency, and verify that the microwave beam doesn’t interfere with existing communications infrastructure. We also have some space science to conduct. We want to be sure that the intense microwave beam isn’t distorted or absorbed by the plasma of the ionosphere, the upper-atmosphere layer that contains electrically charged particles. We’re pretty sure that the beam won’t interact with this plasma, but our hypothesis can be confirmed only in the space environment.

If all goes well with these initial ground and space demonstrations, things will really start to get interesting. JAXA’s technology road map calls for work to begin on a 100-kW SPS demonstration around 2020. Engineers would verify all the basic technologies required for a commercial space-based solar power system during this stage.

Constructing and orbiting a 2-megawatt and then a 200-MW plant, the next likely steps, would require an international consortium, like the ones that fund the world’s giant particle physics experiments. Under such a scenario, a global organization could begin the construction of a 1-GW commercial SPS in the 2030s.

It would be difficult and expensive, but the payoff would be immense, and not just in economic terms. Throughout human history, the introduction of each new energy source—beginning with firewood, and moving on through coal, oil, gas, and nuclear power—has caused a revolution in our way of living. If humanity truly embraces space-based solar power, a ring of satellites in orbit could provide nearly unlimited energy, ending the biggest conflicts over Earth’s energy resources. As we place more of the machinery of daily life in space, we’ll begin to create a prosperous and peaceful civilization beyond Earth’s surface.

This article originally appeared in print as “It’s Always Sunny in Space.”

source: http://spectrum.ieee.org/green-tech/solar/how-japan-plans-to-build-an-orbital-solar-farm

The U.S. Mid-Atlantic Coast at night from the International Space Station.

Image credit: NASA

(https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-prn2/t1.0-9/q77/s720x720/1549416_805568286130851_8333884728513564778_n.jpg)

GSA: 1800 MHz Prime Band for LTE Deployments Worldwide

(http://lteworld.org/sites/default/files/images/LTE_worldwide_310314.jpg)

There are 120 commercially launched LTE1800 networks in 63 countries, according to a recent GSA (the Global mobile Suppliers Association) report. So far 279 LTE networks have been commercially launched in 101 countries. 43% of LTE operators have used 1800 MHz (band 3) spectrum in their networks either as a single band system, or as part of a multi-band deployment.

According to GSA, further 1800 MHz is the prime band for LTE deployments worldwide, and will greatly assist international roaming for mobile broadband. Many more LTE1800 network deployments are in the pipeline.

In addition, 1800 MHz now also has the largest user devices ecosystem. 37% of all LTE user devices support LTE1800 band. More than 50% of newly launched user terminals support 1800 MHz spectrum. A total of 589 LTE1800 user devices have been announced, a annual growth of 152%.

Πηγή: http://lteworld.org/blog/gsa-1800-mhz-prime-band-lte-deployments-worldwide

Huawei Completes 300 Mbps LTE-A Category 6 Test

Huawei has announced the successful completion of a LTE-Advanced (LTE-A) Category 6 connectivity test with download speeds reaching up to 300 Mbps. This test was jointly completed with Qualcomm Technologies.

The test utilized SingleRAN equipment available from Huawei and Qualcomm Technologies’ fourth-generation multimode LTE modem – the Qualcomm® Gobi™ 9x35. Qualcomm's Gobi™ is commercially available cellular modem and manufactured on 20 nm process.

A peak download speed of up to 300 Mbps was made possible, with added support for up to 40MHz wideband carrier aggregation.

Source: http://lteworld.org/news/huawei-completes-300-mbps-lte-category-6-test

AT&T Plans 4G LTE In-Flight Connectivity Service

U.S. carrier AT&T plans to launch a 4G LTE-based in-flight connectivity service for airlines and passengers in commercial, business and general aviation. The service, planned to be available as soon as late 2015, will be capable of providing in-flight broadband for customers including fast, reliable Wi-Fi and onboard entertainment.

To deliver this new service, AT&T plans to build an air-to-ground network in the continental United States, based on LTE standards, to provide fast speeds and efficient utilization of spectrum already owned by AT&T.

AT&T plans to work with Honeywell to provide hardware and service capabilities to deliver the in-flight connectivity solution. According to AT&T, its in-flight connectivity also offers the potential for improved communications between the plane and the ground through transmission of real-time aircraft data for optimizing, monitoring and evolving airlines’ operations.

Source: http://lteworld.org/news/att-plans-4g-lte-flight-connectivity-service

Vehicle communications for safety: eCall fundamentals and test solutions

This webinar provides insights into the underlying key technologies of the eCall system, highlights the test requirements and demonstrates powerful test solutions for the verification of eCall modems to ensure standard-compliant operation.

https://www.youtube.com/watch?v=qYdG3VLeWYI

https://www.youtube.com/watch?v=qYdG3VLeWYI#t=22

Telecom NZ to Trial LTE in 700 MHz Band

Telecom New Zealand plans to begin trial of LTE network over APT700 MHz spectrum next month. The upcoming trial will be conducted in conjunction with Huawei Technologies over 11 cell sites spread across three Waikato locations including central Hamilton and the Mystery Creek Events Centre.

Telecom will use Huawei wireless routers for testing purposes, meaning access to the trial network will be limited to those involved in the trial. Testing will begin in late May and run for approximately four weeks. The non-commercial trial will involve select customers.

While New Zealand Government’s 700 MHz spectrum auction has not yet concluded, the Ministry of Business, Innovation and Employment (MBIE) has approved temporary use of the spectrum for trial purposes.

Telecom has already committed to buy 700 MHz spectrum in the Government’s auction and plans to deploy this spectrum once the auction process has concluded.

According to the operator, the 700MHz spectrum will be important in bringing affordable 4G mobile data services to most of New Zealand, as it delivers greater reach and enhanced in-building coverage over other higher band frequencies. This makes it more efficient to build and ideally suited for delivering 4G services in regional areas.

Source: http://lteworld.org/news/telecom-nz-trial-lte-700-mhz-band

LTE Capacity Webinar

AIRCOM International webinar, focusing on LTEi Capacity and capability

https://www.youtube.com/watch?v=07wrrzlD7AE

https://www.youtube.com/watch?v=07wrrzlD7AE

IEEE Communication Magazine

http://telekomt.files.wordpress.com/2013/03/comg_20120601_jun_2012.pdf

Ρίξτε μια ματιά στο LTE-A και από εδώ  ;)

LTE- Advanced (3GPP Rel.11)
Technology Introduction

http://cdn.rohde-schwarz.com/dl_downloads/dl_application/application_notes/1ma232/1MA232_1E_LTE_Rel11.pdf

Carrier aggregation –
(one) key enabler for LTE-Advanced

http://cdn.rohde-schwarz.com/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/Article_Carrier-aggregation.pdf

Antenna Evolution: Meeting the demand for LTE Small Cell & DAS networks

Implementations of Small Cell and DAS systems have many challenges; not the least of which is the selection and placement of the antenna elements. Since these systems deploy antennas close to the users, additional municipal and building owner restrictions may be enforced. The physical space provided for antenna installation is often limited and concealed when possible. Further, the input power is considerably less than for macro networks making PIM less of a concern than for outdoor networks. These factors make designing Small Cell and DAS systems significantly different from designing macro networks. In this webinar, these differences will be presented in addition to best known design practices.

http://lteworld.org/video/antenna-evolution-meeting-demand-lte-small-cell-das-networks

Vehicle communications for safety: eCall fundamentals and test solutions

This webinar provides insights into the underlying key technologies of the eCall system, highlights the test requirements and demonstrates powerful test solutions for the verification of eCall modems to ensure standard-compliant operation.

https://www.youtube.com/watch?v=qYdG3VLeWYI

https://www.youtube.com/watch?v=qYdG3VLeWYI

Rohde & Schwarz webinar: Wi-Fi traffic offload in LTE

https://www.youtube.com/watch?v=hySj-naUUZE

https://www.youtube.com/watch?v=hySj-naUUZE

LTE Direct Overview

Description:

LTE Direct is a new and innovative direct device-to-device technology for operator enabled proximity services. LTE Direct offers a high capacity, privacy sensitive and battery efficient way to autonomously discover 1000s of devices/services in the proximity. LTE Direct is a candidate feature for 3GPPR12.

http://www.qualcomm.com/media/documents/lte-direct-overview-0

Live Webcast: Three Astronauts Head to ISS
Read more at http://www.iflscience.com/space/live-webcast-three-astronauts-head-iss#eJfVzXQXGVMbax9y.99

Huawei Successfully Tests Next Generation 10Gbps Wi-Fi

[Shenzhen, China, May 29, 2014]: Huawei, a leading global information and communications technology (ICT) solutions provider, today announced that it has successfully achieved the industry’s first 10Gbps Wi-Fi service in laboratory trials at Huawei’s campus in Shenzhen. This important milestone, which delivered data over Wi-Fi 10 times faster than the fastest existing Wi-Fi capability commercially available today, will enable a new era of big data applications by using ultra-fast Wi-Fi technology based on advanced next generation architecture to boost data rates to 10Gbps.

The 10Gbps Wi-Fi prototype achieved a record transmission data rate of 10.53Gbps on 5GHz frequency bands. The success of this prototype development, and the ten folds increase in spectrum efficiency that made it possible, paves the way for the validation of technologies needed to support the creation of next generation Wi-Fi. Huawei believes that ultrafast Wi-Fi could become commercially available from 2018 pending the agreement of global standards requirements and sufficient chipset availability.

As the demand for ultra-fast connectivity for smartphone applications continues to drive the need for higher data transmission rates, the next generation of WiFi access will need to deliver a better user experience, especially in densely populated environments requiring high density deployment such as enterprise offices, airports, stadiums, shopping malls and coffee shops.

To address this growing need, Huawei launched next generation Wi-Fi technology research in 2010 to focus on innovation surrounding new WiFi architectures that would break the logjam of classical WiFi wideband radio and baseband processing to increase user data rates. By utilizing innovative technologies such as MIMO-OFDA, intelligence spectrum allocation, interference coordination and hybrid access, the next generation of Wi-Fi networks will provide dense networking for ultra-hot-zone services with a tenfold increase in spectrum efficiency.

Huawei continues to actively promote and invest in the research and development of advanced technologies for WiFi and is recognized as a leading contributor to the development of next generation WiFi standards. At the Institute of Electrical and Electronics Engineers (IEEE) 802.11 WLAN standard plenary meeting held from May 12-15, 2014 in Hawaii, Dr. Osama Aboul Magd from Huawei was elected as the 802.11ax WLAN standard task group chair to focus on the development of the next generation 10Gbps WiFi standard planned for commercial launch in 2018.

source: http://pr.huawei.com/en/news/hw-341651-ict.htm#.U4oQp5SSyzd

Report: Small cells vital to LTE deployments

http://www.rcrwireless.com/article/20140513/wireless-infrastructure-2/report-small-cells-vital-lte-deployments/

Εκτόξευση κοινού δορυφόρου από Hellas Sat - Inmarsat

(http://www.naftemporiki.gr/fu/p/817282/638/399/0x0000000000b93254/2/ektokseusi-koinou-doruforou-apo-hellas-sat-inmarsat.jpg)

Η Hellas Sat και ο Inmarsat υπέγραψαν συμφωνία για την εκτόξευση κοινού δορυφόρου, ο οποίος θα φέρει εξοπλισμό που θα αφορά δύο ξεχωριστές χρήσεις.
Η πρώτη χρήση θα αφορά τις κινητές δορυφορικές υπηρεσίες S Band της Ευρωπαϊκής Ένωσης, με την επονομασία EuropaSat, οι οποίες αναπτύσσονται μετά την αδειοδότηση του Inmarsat από την Ευρωπαϊκή Ένωση τον Μάιο του 2009, με σκοπό την παροχή δορυφορικών υπηρεσιών διασύνδεσης αεροπορικών επιβατών σε Πανευρωπαϊκή κάλυψη.
Η δεύτερη χρήση θα σχετίζεται με την εγκατάσταση συνολικά 44 αναμεταδοτών, με την επονομασία Hellas Sat 3, οι οποίοι θα χρησιμοποιηθούν αποκλειστικά για την αντικατάσταση του υφιστάμενου δορυφόρου Hellas Sat 2 και για την περαιτέρω ανάπτυξη των δορυφορικών επικοινωνιών της Hellas Sat.
Ο κοινός δορυφόρος θα κατασκευαστεί από τη γαλλική εταιρεία Thales Alenia Space και η εκτόξευση προγραμματίζεται για το 2016.
Ο διευθύνων σύμβουλος της Hellas Sat, κ. Χριστόδουλος Πρωτοπαπάς, δήλωσε σχετικά: «Η Hellas Sat θα συνεχίσει να αναπτύσσει την τροχιακή θέση των 39 μοιρών Ανατολικά ώστε να καταστεί μια από τις κυρίαρχες θέσεις για την παροχή καινοτόμων τηλεοπτικών υπηρεσιών».
«Ο  νέος δορυφόρος Hellas Sat 3 - IS, ο οποίος θα ελέγχεται από ελληνικό έδαφος από τους μηχανικούς της Hellas Sat, θα εξυπηρετήσει τους υφιστάμενους και μελλοντικούς πελάτες της εταιρείας με επιπλέον δορυφορική χωρητικότητα», συμπλήρωσε ο κ. Πρωτοπαπάς.
Επιπλέον, η εταιρεία σκοπεύει να προχωρήσει σε μια ακόμη εκτόξευση, εντός του 2017, ενός ακόμη δορυφόρου με την ονομασία Hellas Sat 4, με ευρεία και ισχυρή δορυφορική κάλυψη στην Ευρώπη, Μέση Ανατολή και Αφρική για πολλαπλές και καινοτόμες υπηρεσίες δεδομένων και δορυφορικής τηλεόρασης.
Τέλος, αξίζει να σημειωθεί ότι ο Inmarsat (International Maritime Satellite Organization) είναι διεθνής τηλεπικοινωνιακός οργανισμός, με έδρα το Λονδίνο, ο οποίος προσφέρει παγκόσμιες δορυφορικές επικοινωνίες με έμφαση στον τομέα της ναυτιλίας. Ο οργανισμός, που ιδρύθηκε το 1979, αποτελείται από 86 κράτη-μέλη, μεταξύ των οποίων και η Ελλάδα.

Πηγή: http://www.naftemporiki.gr/story/817281/ektokseusi-koinou-doruforou-apo-hellas-sat-inmarsat