Research On Cooperative Relay Strategy And Resource Allocation For Wireless Relay Communication Networks

With the rapid development of wireless communication technology, the cooperative relay communication and cognitive radio technology have become people’s research hotspots.The application of these technologies in wireless communication system, which not only can effective against multi-path and ensure the quality of communication, but also can increase the spatial diversity gain and increase system capacity as the cooperation of different users, then the spectrum utilization will be improved.At present, based on the single relay cooperative communication technology, this paper researches single relay cooperative communication system、the diversity gain、 the diversity and merging technologies, and then analysis the different relay cooperative system. The single relay cooperative system includes a source node, a destination node and a relaying node, which consist three transmission links:the direct transmission link, the relaying transmission link between the source node and the relaying node, another relaying transmission link between the relaying node and the destination node.On the basis of the system model, the emulation of different relay cooperative is obtained:when there has a direct transmission link in the system, the system will has a better bit error rate in DF relay than the AF relay; and when the direct transmission link isn’t existing, with the increasing of the system SNR,the advantage of the bit error rate in DF relay will be lose, and the anti-interference ability will be enhance.Secondly, based on the theories of AF relay cooperative technology and DF relay cooperative technology, this paper proposed a signal-user hybrid relay cooperative system model and the corresponding power allocation scheme, which can give the better system throughput and the higher system energy efficiency. The simulations reveal that no matter with the increase of the system power or the system SNR,the hybrid relay cooperative system both can obtain better system throughput and higher system energy efficiency. The hybrid relay cooperative system selects the AF relay cooperation or the DF relay cooperation adaptively to transmit the information, in this way, it can overcome the malpractice of the traditional signal relay cooperation, and then also can improve the system through and the system energy efficiency, which enhanced the resource utilization of the system.Finally, this paper further discussed the cognitive radio technology based on the relay cooperative technology. And then combined with the technologies, this paper proposed the Multi-Group Multi-Cast CR networks model, which based on the inter-group and inner-group cooperation. The optimal resource allocation scheme is also proposed to present the variation of the system throughput. The simulations reveal that:with the increase of the users in the Multi-Cast group, the corresponding group’s weight factor of rate will be larger, which would improve the Multi-Cast group’s rate. So the Multi-Group Multi-Cast CR networks model can improve the rate of the Multi-Cast group that has more users.