The Research Of Power Allocation For Relays In Wireless Commu Nication

Relay-based cooperative communication has attracted a great deal of attentions in wireless communication research community. This thesis includes some research on optimal power allocation for relay systems. First, this thesis gives optimal power allocation scheme for dual-hop single amplify-and-forward relay system in which the direct path is also considered. Then this thesis gives optimal power allocation scheme for dual-hop two amplify-and-forward relay system in which the direct path has been taken into consideration. And this thesis also gives optimal power allocation scheme for dual-hop mutiple amplify-and-forward relay system with direct path. Finally, this thesis proposes optimal power allocation scheme for dual-hop amplify-and-forward relay network, where an aggregate relay power constraint and independent power constraint with both upper bound and lower bound are imposed on all the relays, the channels are assumed to be frequency-flat fading. The dual-hop relay system this thesis study only contains one source node and one destination node. When the channel is frequency selective fading, the optimization objective is to maximize system instantaneous communication rate. When the channel is frequency flat fading, the optimization objective is to maximize instantaneous output SNR.