Research Of Network Space-Time Coding For Wireless Relay Network

This thesis studies some issues of the multi-source multi-relay wireless network. Based on characteristics of the wireless relay network, we proposed the design of network space-time codes. After a brief introduction of the relay coding, network coding and space-time coding, some typical relay coding strategies are discussed. Then two new coding schemes, distributed network space-time coding and network space-time coding, are proposed.For the distributed network space-time coding, a distributed complex field network space-time code, which combines the network coding with the distributed Alamouti's code, is designed for the multi-source two-relay distributed network using decode-and- forward protocol. Because both the channels between sourced and relays and the channels between relays and destination are synthetically considered, the relays control their power adaptively and over the shortcoming of DF protocol which hardly gain full diversity.For network space-time coding ,a complex field network space-time code, which combines the network coding with the Alamouti's code, is designed for the multi-source distributed network with one two-antenna relay using decode-and- forward protocol.Due to the adoption of the space-time code which has excellent performance in multi-source network and the flexible of the precoding vectors used by the relay node and the source nodes, the proposed network space-time codes and distributed network space-time codes can improve the system performance, achieve more efficient throughput and provide maximum cooperative diversity gain.