On the study of high spectrum efficiency relay networks

• Main Author: Luo, Chunbo
• Published: University of Reading 2011
• Subjects: 004.68
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553131

In the cooperative networks, in order to combat the 50% spectrum efficiency loss of the half-duplex limit imposed on most of the mobile terminals, this thesis studies the high efficiency two-path model and proposes the selective two-path model to recover the efficiency loss and explore the diversity. In the two-path succussive relay cooptative transmission, the 50% loss in data rate can be well avoided because the source can continuously transmit to two relays alternatively. Due to the concurrent transmission from source and relays, however, inter-relay interference may significantly damage the performance. Various practical interference cancellation algorithms are introduced in the thesis. Two practical relay protocols for the two-path model are studied: the amplify-forward protocol and decode-forward protocol. With the application of these two protocols, the interference emerges with different effects towards the final received signal. As demonstrated in the simulation parts, we show that the proposed algorithms can suppress the interference effectively, thus achieve satisfied performance without the sacrifice of other resources, e.g. time, frequency or space. " With the help of information theoretical tools, the analysis of the proposed selective two-path model proves that it can achieve diversity order of M if there are M potential relay candidates. Such diversity is obtained without the reduction of spectrum efficiency. The selective two-path model can combat the fading of wireless channels and improve the robustness of the system without the cost of power or bandwidth. With the recovered 50% spectrum efficiency, such model can be used in the cooperative networks which require high data rate and spectrum efficiency, for example, cellular networks or wireless sensor networks.