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A New Trade-off Scheme for MIMO
OFDM-based Cognitive Radio
Systems over Correlated Fading Channels
1
1: Makan Zamanipour
IEEE Member Tehran, Iran
2: Saeed Mashhadi
Sharif University of Technology Tehran, Iran
17th FRUCT: 20-24 April, 2015, Yaroslavl
Preface
Introduction Assumptions
Correlated MIMO Channels
Challenges/Motivations
Trade-off Scheme Network Model
Problem Formulation System Model
OSTFB Coding in MIMO OFDM Scheme
Optimization Problem
Robust Beamforming
Results
17th FRUCT: 20-24 April, 2015, Yaroslavl 2
Introduction Assumptions
Channels: Quasi Static Rayleigh
Frequency Selective Fading
Domain: Frequency
Cognitive Radio: Underlay Scenario
Transmit-receive Scenario: Down-link Multi-user Scenario
17th FRUCT: 20-24 April, 2015, Yaroslavl 3
Antenna Distance Carrier Frequency ...... 2
d
Transmit-Angle Spread
17th FRUCT: 20-24 April, 2015, Yaroslavl 4
Introduction Correlated MIMO Channels
Introduction Challenge/Motivation
17th FRUCT: 20-24 April, 2015, Yaroslavl 5
Kronecker Model:
Introduction Challenge/Motivation
17th FRUCT: 20-24 April, 2015, Yaroslavl 5
Introduction Challenge/Motivation
Solution: Pre-coding/Post-coding
17th FRUCT: 20-24 April, 2015, Yaroslavl 6
Introduction Challenge/Motivation
Solution: Pre-coding/Post-coding
17th FRUCT: 20-24 April, 2015, Yaroslavl 6
Yes No
Effect
on
SNR
Effect
on
SNR
17th FRUCT: 20-24 April, 2015, Yaroslavl 7
Trade-off Scheme Network Model
17th FRUCT: 20-24 April, 2015, Yaroslavl 7
Trade-off Scheme Network Model
Small Eigen-values
OSTFBCs
17th FRUCT: 20-24 April, 2015, Yaroslavl 7
Trade-off Scheme Network Model
Small Eigen-values
OSTFBCs
17th FRUCT: 20-24 April, 2015, Yaroslavl 7
Trade-off Scheme Network Model
Secrecy: Probability of Eavesdropping
17th FRUCT: 20-24 April, 2015, Yaroslavl 8
Problem Formulation System Model
17th FRUCT: 20-24 April, 2015, Yaroslavl 9
Problem Formulation OSTFB Coding
Frequency Selective Fading Channels
Problem Formulation Optimization Problem
17th FRUCT: 20-24 April, 2015, Yaroslavl 10
Problem Formulation Optimization Problem
17th FRUCT: 20-24 April, 2015, Yaroslavl 10
Problem Formulation Optimization Problem
17th FRUCT: 20-24 April, 2015, Yaroslavl 10
17th FRUCT: 20-24 April, 2015, Yaroslavl 11
Problem Formulation Optimization Problem
Decrease in Search Region
Small Eigen-values: As much as Possible
17th FRUCT: 20-24 April, 2015, Yaroslavl 12
Lagrange Method:
A Closed-form Solution (THEOREM 4)
Problem Formulation Optimization Problem
Problem Formulation Robust Beamforming
17th FRUCT: 20-24 April, 2015, Yaroslavl 13
Estimation of Correlation Matrices: Error
Solve the Problem in Worst Case
Problem Formulation Robust Beamforming
17th FRUCT: 20-24 April, 2015, Yaroslavl 13
Results
17th FRUCT: 20-24 April, 2015, Yaroslavl 14
Complexity Should be Examined!
17th FRUCT: 20-24 April, 2015, Yaroslavl 15