4_DVBT_CR_ASU_Dr_Salwa_ElRamly

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Enhancement Proposals for DVBT-2Systems and Cognitive Radio NetworksSharing the Same Frequency Band

Phase 1 ReportBy

Prof. Dr. Salwa ElramlyElectronics & Communications Engineering Department

Faculty of Engineering, Ain Shams University

12/10/2011 1CSPRL


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Agenda

Introduction

WARP Lab Establishment

DVBT-2 System

Cognitive Radio: System Overview and Futuretrends

Multiple Access and Routing in CR Networks. Conclusions & Future Work

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Introduction The research project is executed in the

Communications& Signal Processing Lab

(CSPRL)(for more info visit www.csprl-eng-asu.org)

The research project started 15/3/2011 forthe duration of 2 years and to be executed in

4 phases. The team is composed of 1 Professor, 4

Assistant Professors and 7 ResearchAssistants.

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http://www.csprl-eng-asu.org/http://www.csprl-eng-asu.org/http://www.csprl-eng-asu.org/http://www.csprl-eng-asu.org/http://www.csprl-eng-asu.org/http://www.csprl-eng-asu.org/http://www.csprl-eng-asu.org/


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Team Members Prof. Salwa Elramly (PI)

Dr. Hussein Abdel Aty

Dr. Maha Elsabrouty

Dr. DiaaEldin Khalil Dr. Fatma Newagy

Eng. Mona Zakaria

Eng. Bassant Abdelhameed

Eng. Betty Nagy

Eng. Mohammed El-Bayoumi Eng. Hannan Hussein

Eng. Mayada Mamdouh

Eng. Hannan Debaiky

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Objectives The project has two objectives:

1. Research objective

2. Educational objective

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Research Objectives The project research part is comprised of:

Theoretical work, searching for newalgorithms to enhance the treated systems

Implementations of some of thesealgorithms, seeking low complexity and low

power consumption. To achieve this goal, a WARP laboratory is

planned to be established in CSPRL.

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Research Objectives Cont. The work in this project is subdivided into two

directions, one is concerned with Cognitive Radio andthe other is concerned with DVB-T2 which is

expected to share the same frequency band. Thesetwo directions are further subdivided to three tracks:

Track1: Cognitive Radio Physical Layer: Design andChallenges.

Track2: Multiple Access and Routing in CR Networks. Track3: Working on Second Generation Digital

Terrestrial Television Broadcasting System (DVB-T2).

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Educational Objectives Cont. The project also has an educational part aiming to have

graduates with good knowledge of the DVB-T2 system whichwill be implemented in Egypt in the near future (2015 imposed

by ITU). Graduation projects is found to be a good tool to achieve this

goal for System understanding, analysis, simulation andimplementation.

Short courses will be prepared for graduates for Continuous

Education Program. MSc. And PhD thesis can be concentrated on topics related to

the project. ( 2 PhD and MSc. Are already registered for)

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WARP Overview Wireless Open-Access Research Platform developed

at Rice University.

Scalable and extensible programmable wirelessplatform, to prototype advanced next generationwireless networks.

Open-access repository to share knowledge acrossresearch community

Useful in improving wireless curricula, where it isused as an excellent vehicle for education labs todemonstrate both non real-time and real-timewireless communication.

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WARP Overview

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WARP offers scalability and programmability of bothphysical and network layer protocols on single platform.

Complete system with custom hardware, supportpackages, design tools and application libraries.

Conceptually divided into four main parts:

Hardware

Support packages

Research applications

Open-access repository


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Why Adopt WARP? The better specifications and abilities of WARP

hardware compared to other platforms in the market.

The great use of the open-access WARP repository,maintained by the WARP team at Rice University, toprovide technical knowledge and support and also topromote team-work and international collaboration.

The great use as an excellent vehicle for educationlabs to demonstrate both non real-time and real-timewireless communication.

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WARP LAB Establishment

The WARP laboratory is incubated inside CSPRL.

It is established as a partition of CSPRL, in the form

of rectangular area of 25 m

2

. The required equipments are funded by NTRA.

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WARP LAB Equipment List

Complicatedprocess for WARPhardware purchase(expected done byend of october.~14 weeks fordelivery)

PCs ordered anddelivered

Printer ordered anddelivered.

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Item Qty

WARP MIMO Kit v2.0 3

WARP radio daughtercard v1.4 2

WARP analog daughtercard v1.1 3Wi-Fi Spectrum Analyzer 1

8-Port Wired Switch 1

Network Cable 5m 7

USB Cable A-B 3

CompactFlash Card Reader 2

Personal Computer 4

All-in-One Printer 1

Electrostatic Protection Glove (Pair) 3

Electrostatic Protection Bench Mat 3


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WARP Documentation & Training

WARP repository is wiki-based scattered information

Work started to develop high quality documentation &

training materials Simple and complete reference manual

Training materials tailored to the needs of our team

Establish team step-by-step knowledge gain using

seminars and demos for practical experience Seminar1 (2/7/2011): Overview of WARP system and

the details of its different hardware components

Seminar2 (8/9/2011): WARP physical layer

implementation flow through WARPLab12/10/2011 14


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About DVB-T2 DVB-T2 system will be implemented in Egypt in the

near future (expected 2015).

This system transmits compressed digital audio,video, and other data in "physical layer pipes" (PLPs),using OFDM modulation with concatenated channelcoding and interleaving.

It has been standardized by EuropeanTelecommunication Standardizations Institute (ETSI)since September 2009.

It is implemented in many European Countries.

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16

DVB-T2 Block Diagram

InputData

OutputData

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DVB-T2 vs. DVB-T

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DVB-T2 DVB-T

FEC LDPC + BCH CC + RS

Code Rate 1/2, 3/5, 2/3, 3/4 , 4/5, 5/6 1/2, 2/3, 3/4, 5/6, 7/8

Constellation QPSK, 16 QAM, 64 QAM, 256

QAM ( with rotation)

QPSK, 16 QAM, 64 QAM

Guard Interval 1/4 , 19/256, 1/8, 19/128,1/16, 1/32, 1/128

1/4, 1/8, 1/16, 1/32

FFT size 1K, 2K, 4K, 8K, 16K, 32K 2K, 8K

Scattered pilots 1%, 2%, 4%, 8% of total 8% of total

Continual pilots 0,35% of total 2.6% of total

Bandwidth 1.7, 5, 6, 7, 8, 10 MHz 5, 6, 7, 8 MHz

Interleavers Bit, Cell, Time& Frequency Outer & Inner

Max.

Bandwidth

50,34 Mbps 31,66 Mbps

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New TechnologiesUsed in DVB-T2

Low density parity check codes (LDPC) +BCH codes.

Constellation rotation. Four levels of interleaving

Bit interleaving

Cell interleaving

Time interleaving

Frequency Interleaving

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Constellation Rotation

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Constellation Rotation ( cont.)

Rotated constellation consists of applying arotation to the QAM constellation followed bycomponent-axes interleaving.

The insertion of the interleaving between I andQ leads to the same information being senttwice over the channel in different cells.

This leads to additional diversity that improvesthe error-correcting performance whenseverely faded channels are encountered.

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Simulation Results

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Simulation Results cont.

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Cognitive Radio:Interference mangement & Powercontrol

Team:

Dr. Maha Elsabrouty

Eng. Bassant AbdelhamidEng. Betty Ngui

Eng. Mohamed Elbayoumi

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24 Maha Elsabrouty12/10/2011 24


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25 Maha Elsabrouty

Cognitive Radio

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26 Maha Elsabrouty

What is cognitive Radio ?

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27 Maha Elsabrouty

Transmission Scenarios:

Overlay(int.mitigation)

Interweave (int.avoidance)

Underlay(int. controlling)(space pooling)(spectrum sharing)

SUtransmissionw.r.t PU

Simultaneously Separated except infalse detection

Simultaneously as long asPU interference belowinterference limit

SU knowledge PU codebooks,channel gains

The spectral holes inspace, time, or

frequency.

The channel strengths toPU receiver

SU transmitpower

Any power Limited by the rangeof its spectral holesensing

limited by the interferenceconstraint

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28 Maha Elsabrouty

Beamforming

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29 Maha Elsabrouty

Mathematical Model:

Objective

Subject to

Beamforming in CognitiveRadio Model

0

22

,

2,

, NwwH ksw

wH ssw

SINR

rsw

tsw

Max

rstk

H

rs

ts

H

rs

max,

2

2

,,....,1

sts

ktssk

H

rk

Pw

KkwHw

Note ! All signals are normalized i.e. 122

ksxExE

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30 Maha Elsabrouty

Interference Alignment in CR

*Notice of Proposed Rule Making (NPRM) 8/12/00

Achieving:Basic goalmaximum multiplexing gain

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31 Maha Elsabrouty

New Research Directions inCR interference control and mitigation

(1) Considering Channel Imperfections inBeamforming and Interference Alignment.

(2) Game theory application in IA andbeamforming.

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32 Maha Elsabrouty

max,

2

2

,,....,1

sts

ktssk

H

rk

Pw

KkwHw

Mathematical Model:

Objective

Subject to

Beamforming in CognitiveRadio Model

0

22

,

2,

, NwwH ksw

wH ssw

SINR

rsw

tsw

Max

rstk

H

rs

ts

H

rs

Note ! All signals are normalized i.e. 122

ksxExE

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33 Maha Elsabrouty

IA with channel imperfection

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34 Maha Elsabrouty

Research papers

34

[1] ICC 2012: B. Abdelhamid, M. Elsabrouty, M. Alghoniemy , S.Elramly : Opportunistic Interference Alignment for MIMO Cognitive

Networks with Channel Imperfection, submitted

Contribution: Developing a new power allocation to preserve the

maximize the capacity in channel imperfection scenario.

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35 Maha Elsabrouty

(3) Using Game theory forBeamforming and IA

Motivation: In interference alignment precoding and postcoding matrices are

calculated with every new update in the channel matrices and sentto the respective recievers.

In beamforing the beamforming vector is clacluated with the everyupdate of the channel matrices and sent to the respectivereceivers.

Idea:

1. replace the actual coefficients with coefficients table.

2. choose among available coefficients instead of calculation.

3. Send index instead of the actual coefficients to the recievers.

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36 Maha Elsabrouty

Cross layer Power ControlUsing Game Thoery

Modifying the power of each secondary useraccording to the channel conditions.

Feedback from physical layer.

Involves modifying the different definitions ofgames to suit the special nature of the CR.

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37 Maha Elsabrouty

Conclusion

Cognitive Radio is a promising technology tofully utilize the spectrum resources and provideservice for emergency users.

Interference control/ Management / Mitigation

are key for the proposer setup of cognitive radiosystem.

New ideas can emerge in the cognitive radioscene with possibility to improve the

performance.

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38 Maha Elsabrouty

Reference Publications

Mitola, Cognitive Radio for Flexible Mobile Multimedia Communications,

IEEE Mobile Multimedia Conference, 1999, pp3-10

Mitola, Future of Signal Processing - Cognitive Radio, Keynote, IEEE

ICASSP, May 1999

Beibei Wang, Yongle Wu, K.J. Ray Liu, "Game theory for cognitive radio

networks: An overview", ELSEVIER journals on Computer Networks 54

(2010) 25372561

V. R. Cadambe and S. A. Jafar, Interference alignment and degrees of

freedom of the K-user interference channel, IEEE Trans. Inf. Theory, vol.

54, no. 8, pp. 34253441, Aug. 2008.

Ying Jun (Angela) Zhang,Member, IEEEand Anthony Man-Cho So,

Optimal Spectrum Sharing in MIMO Cognitive Radio Networks via

Semidefinite Programming, IEEE Journal On Selected Areas In

Communications, Vol. 29, No. 2, February 2011

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Multiple Access and Routingin CR Networks

Phase 1 Activities:

Building background on CR.

Survey of the existing Multiple Accessand Routing protocols.

Acquiring OpNet simulation tool skills.

Analysis of existing models.

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CR Networks (Layers)

BS BS

Layer 2channelassignment

Layer 3

Routing/handover

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MAC Protocol for CRN

Desired features:

- Predicting future spectrum usage.

- Bundling several continuous idle channels.

- Distributed algorithm to be employed in ad-hoc networks.

- Dealing with multi channel hidden terminal problem.

Objectives:

- Increase throughput.

- Reduce interference between SU and PU.

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Different Types of MAC Protocols

KNOWS (Kognitiv Networking Over WhiteSpace).

AS-MAC (Ad Hoc Secondary system-MAC). SYN-MAC (SYNchronized-MAC).

SCA-MAC (Statistical ChannelAllocation-MAC).

ECR-MAC (Energy efficient Cognitive Radio-MAC).

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Cognitive radioAd-Hoc routing protocols

- Desired featuresAllow the secondary users to communicate with eachother without base station or access point.

Build routes from source to destination using low metric.Avoid the primary user region during the build of theroutes.

- Objectives Improve some performance metric such as utilizationand throughput.

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Performance metrics

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CRAHNs routing protocols

Opportunistic Service Differentiation Routing Protocol(OSDRP).

Spectrum-Tree Based On-Demand Routing Protocol forMulti-Hop Cognitive Radio Networks(STOD-RP).

SpEctrum Aware Routing protocol for Cognitive ad-Hocnetworks (SEARCH).

CR Routing Protocol (CRP).

Routing in Mobile Ad-hoc Cognitive RadioNetworks(CAODV).

Connectivity-Driven Routing for Cognitive Radio Ad-HocNetworks.


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Network model

Packet Delivery Ratio vs. number of nodes

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Packet Delivery Ratio vs. number of nodes

Simulation Results

0.54

0.56

0.58

0.6

0.62

0.64

0.66

0.68

0.7

5 10 15 20 25 30 35

PDF


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Routing overhead verses number of nodes

Simulation Results (Cont.)

0

50,000

100,000

150,000

200,000

250,000

5 10 15 20 25 30 35

Routing overhead


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Conclusions & Future Work

The project planned research outcomes wereachieved.

Eight Seminars were held during Phase 1 duration.

WARP Lab establishment suffers delay due to theslow and complicated process of procurements.

One Paper has been sent to an internationalconference, but not yet accepted.

The project plan will be followed in the next 6months (Phase 2).

Documents

4_DVBT_CR_ASU_Dr_Salwa_ElRamly