Power Control And Relay Selection Technology In Two-way Relay Networks

As a new wireless transmission technology,multihop and cooperation communication technology can effectively reduce the effects of fading channel and provide connection between nodes at the low quality links.In the large flow scenarios of next generation network application,the parameters of physical buffer at the relay will influence on the performance of the wireless relay,such as throughput and quality of service(QoS).After reviewing the new technology of the wireless communication and the wireless relay technology,this work mainly studies power control scheme of limited buffer-aided relaying system and the relay selection scheme.For two-top bi-directional information exchange in wireless networks,this thesis considers a power control scheme of the DF-based bi-directional relaying in the configuration of a limited and a non-limited buffer.The numerical results show the size of buffer at the relay will not affect average end-to-end capacity over the Rayleigh fading channel while the size of maximum buffer is set as to an appropriate value.In addition,optimal power control will significantly improve the average end-to-end capacity of the transmission strategy compared to that of the equal power control scheme.Secondly,this work studies half-duplex relay strategy,which can improve the spectrum efficiency and support bi-directional service at the same time.This work also gives an optimal power control scheme when the transmitters of source nodes have the channel amplitude information.Compared with the bi-directional one-way relay transmission strategy,the DF relaying has significant end-to-end capacity performance gain,and also has the advantages of saving transmission time slot and saving energy consumption in the whole signal-to-noise ratio area.Finally,the end-to-end capacity performance gain of the smaller buffer size of multiple relay selection scheme in the low signal to noise ratio area is better than that of the bigger buffer size of one relay system scheme,while the end-to-end capacity performance gain of the bigger buffer size of one relay system scheme better in the high signal to noise ratio area.