Efficient receiver design for cooperative wireless networks over fading channels

Abstract

Cooperative transmissions exploit the benefits of Multiple-Input Multiple-Output (MIMO) antennas, by creating virtual antenna arrays to provide spatial diversity and multiplexing gains. Some major challenges in cooperative systems are the time varying nature and the frequency selectivity of cooperative links, which lead to severe Error Rate performance degradation. In this thesis, we first study the multicarrier cooperative transmissions over doubly selective channels. We introduce a novel receiver that enhances the Bit Error Rate (BER) performance of a cooperative system with Space-Frequency Block Coding (SFBC) and Orthogonal Frequency Division Multiplexing (OFDM). We demonstrate that the proposed receiver eliminates the Inter-Carrier Interference (ICI) terms and as a result it reduces the BER error floor caused by the difference in frequency response of the channel over two adjacent subcarriers. Second, given the same cooperative scenario, we present a source precoder design and a relay antenna selection scheme by exploiting the sparsity of the relay gain vector with imperfect channel estimation and spatially correlated antennas at all nodes. For the precoder design, we present a technique which diagonalizes the Mean Squared Error (MSE) matrix to introduce an optimal source precoder design, which aims to minimize the MSE. Extensive Monte Carlo simulation results demonstrate that the performance gain of our proposed schemes over the existing schemes is significant. The simulation results for the proposed schemes show that, considering spatially correlated antennas at all nodes, the proposed model outperforms the other models, even when the antennas are highly correlated.

Date of Award	2014
Original language	American English
Supervisor	Sami Muhaidat (Supervisor)