Transcript
IntroductionCooperative Communications
Research ProblemsSummary
Cooperative Wireless Communications
M. R. Avendi
Communication Theory Research Group (CTRG)University of Saskatchewan
Ph.D. Advisor: Prof. Ha Nguyen
April, 2013
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IntroductionCooperative Communications
Research ProblemsSummary
Outline
1 Introduction
2 Cooperative Communications
3 Research Problems
4 Summary
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IntroductionCooperative Communications
Research ProblemsSummary
Wireless Communications
Bart Simpson
Base Station
wireless channel
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IntroductionCooperative Communications
Research ProblemsSummary
Wireless Fading Channel
Mobile Phone
Base Station
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IntroductionCooperative Communications
Research ProblemsSummary
Wireless Channel Model
transmitted Signal
Received Signalfilter, h
Fading Channel
Additive noise
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IntroductionCooperative Communications
Research ProblemsSummary
Diversity
Channel fading effect: severely degrades performance
Demand for higher date rate and better quality
Diversity: different replicas of signal
Diversity techniques: time, frequency, spatial, ...
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IntroductionCooperative Communications
Research ProblemsSummary
Spatial Diversity
Mobile PhoneBase Station
Multiple Antennas
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IntroductionCooperative Communications
Research ProblemsSummary
Spatial Diversity
Mobile PhoneBase Station
Multiple Antennas!!!
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IntroductionCooperative Communications
Research ProblemsSummary
Cooperative Communications
Users help each other
UserBase Station
Relay
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IntroductionCooperative Communications
Research ProblemsSummary
Challenges
Detection: data recovery from received signalsCoherent Detection
Channel estimation needed: training symbolsThere are more fading channels to estimateSpectral efficiency, overhead, mobility of users
UserBase Station
Relay
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IntroductionCooperative Communications
Research ProblemsSummary
Challenges
Non-Coherent detection
Differential modulation/demodulationNO channel estimation needed3 dB worse than coherent detectionUser’s mobility
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IntroductionCooperative Communications
Research ProblemsSummary
Performance
Performance of a cooperative system in different scenarios
0 5 10 15 20 25 30 35 40 45 50 55
10−6
10−5
10−4
10−3
10−2
10−1
100
Power(dB)
Error
Slow Fast
Very Fast
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IntroductionCooperative Communications
Research ProblemsSummary
Research Problems
Performance evaluation of cooperative networks
Improve performance of the current techniques
Finding new techniques to achieve better performance
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IntroductionCooperative Communications
Research ProblemsSummary
Published Papers
1- M.R.Avendi and Ha Nguyen, ”Selection Combining forDifferential Amplify-and-Forward Relaying Over Rayleigh-FadingChannels”, IEEE signal processing letter, March 20132- M.R.Avendi and Ha Nguyen, ”Differential Amplify-and-ForwardRelaying in Time-Varying Rayleigh Fading Channels”, IEEE WCNCApril 20133- M.R.Avendi and Ha Nguyen, ”Performance of DifferentialAmplify-and-Forward Relaying in Multi-Node WirelessCommunications ”, IEEE Trans. on Vehic. Tech., to appear
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IntroductionCooperative Communications
Research ProblemsSummary
Summary
Wireless channels, fading effects
Diversity, multiple antennas
Cooperative communications
Research problems and current investigations
Thank you!
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