多用户OFDM双向中继权衡公平性和总速率资源优化

Resource Optimization for Fairness and Sum Rate Tradeoff in Multiuser OFDM-Based Two-Way Relaying

在OFDM协作双向中继网络中,当多个用户对借助AF(amplify and forward)双向中继相互通信时,用户对之间的公平性与系统总速率不能同时兼顾.该文提出一种用户对速率成比例性公平,并与系统总速率折中的次优资源分配策略.该策略以最大化双向中继系统总速率为目标,在总功率及用户对的速率成比例约束下分两步进行.首先在每个子载波等功率假设条件下进行用户对速率成比例公平的子载波优化,使系统总速率得以提升.然后在保证公平性前提下采用一种迭代的功率分配方法将总功率分配到各个子载波,使系统总速率再次得到提升.仿真结果表明,所提出的策略在保证用户对速率成一定比例的前提下有效地提高了系统总速率.

In OFDM-based cooperative two-way relay networks,sum rate and fairness among user pairs cannot be achieved simultaneously when these user-pairs exchange their information respectively via an amplify-and-forward two-way relay.This paper proposes a novel suboptimal resource allocation scheme to trade off the proportional fairness and the system sum rate.This scheme is divided into two steps to maximize the sum rate of the system subject to the constraints of total power and proportionality among user-pair data rate.First, sub-carrier optimization is processed with equal power among every subcarrier to achieve proportional fairness and improve the system sum rate.To further improve the sum rate while maintaining fairness,the total power is allocated to every sub-carrier with an iterative power allocation algorithm.Simulation demonstrates that the proposed scheme of resource allocation can achieve good tradeoff between proportional fairness and system sum rate.