Cooperative Node Selection and Power Allocation Strategy in Two-way Relay System
Tang Lun①② Liu Tong① Chen Qian-bin① Zeng Xiao-ping②
①(Key Lab of Mobile Communication Technology, Chongqing University of Posts and Telecommunications, Chongqing 400065, China) ②(The Communication Engineering College of Chongqing University, Chongqing 400044, China)
Abstract：In order to improve the sum-rate of Two-way relay system, this paper proposes a Bi-directional Relay Selection (BRS) scheme in Two-way AF relay system. This scheme selects the optimal relay through joint considering the receive SNR (Signal Noise Rate) at the relay node and the channel gain between relay and destination node; Furthermore, this paper proposes two optimal power allocation scheme in Two-way relay system: (1) Optimal Power Allocation scheme based on Convex Optimization (OPA-CO), (2) Optimal Power Allocation scheme based on the Differences of Channel Gains (OPA-DCG); Scheme (1) establishes the optimal issue that how to maximize the sum-rate of Two-way relay system when total power is limited; Scheme (2) establishes a mathematical optimal model that how to maximize the increment of sum-rate based on the differences of channels gains. This paper uses an iterative power allocation algorithm to solve the optimal model mentioned above for the purpose of reducing the complexity of solving convex optimal mode. Simulation result shows that all the schemes mentioned above can improve the sum-rate.
2010, Vol. 32 
