Research On Multi-antenna Cooperative Relay Transmission Scheme With Two-path Based On Cyclic Delay Forwarding

With the nowadays development in society Internet technology and the rocketing development of mobile multi-media, how to improve the reliability and efficiency of communication network, how to reduce the system bit error rate and the complexity for testing, it has become the hot issues for studies in recent years. Based on the multi-antenna, the Multiple-Input Multiple-Output could improve the system transmit speed and the spectrum efficiency as well. However, because of the limitations of launching power and the complexity of hardware, the following multi cooperative communication schemes are proposed. Among which, the two-path cooperative communication scheme, the source nodes could continuously send new data in different time slot, thus the system could realize the full-speed transmit and has a has a wide prospect.The existing two-path cooperative transmit schemes are all base on the mono-antenna, the system’s maximum capacity is extremely limited. However, if we put multi-antenna in the source node, destination node and each relay node, more space diversity and higher transmit speed could be realized. In order to solve the complexity in the multi-antenna system, the Cyclic Delay Diversity technology is applied during the process of transmitting the relay node. It not only can simplify the complexity of texting structure, it can also improve the spectrum efficiency. Put the linear complex field joint pre-coding technology in the source node, the coding gain and diversity gain could be got. Researching the combination of joint precoding with CDD and multi-antenna has the distinctive features of low detection complexity and is able to realize the reliable, full-rate transmit two-path multi-antenna cooperative, providing the theoretical support and methods of the practical use for wireless cooperative communication technology. In this thesis, the main research contents and innovation points are as follows:(1) Turning the traditional two-path full rate cooperating relay scheme to the scheme that applying multi-antenna in all relay nodes and destination nodes, analyzing the transmit model and the performance of the multi-antenna system.(2) Designing the multi-antenna joint pre-coding scheme, joint precodes all antenna symbols in all time slots on the transmitting terminal. Through joint pre-coding, the system could get the maximum diversity gain and certain coding gain, the BRE performance of the system could be improved as well.(3) The pass-through mode adopted in the relay node is the cyclic relay diversity. By theoretical derivation and simulation experiment, the thesis finds that although the multi-antenna’s applying on all nodes would raise the complexity of the system, by adopting the cyclic relay diversity transmit, the complexity of testing could be unacted to the increasing number of relay nodes.This transmit scheme coding is easy and possible to be realized, relay forward could be realized by combing with other coding scheme. It has certain universal property and expansibility, there is high practical value in this thesis.