基于比例速率保证的信道误差OFDMA中继系统资源分配

Proportional Rate Constraint Resource Allocation for OFDMA Relay Systems with Channel Estimated Error

针对存在有信道估计误差的正交频分多址(OFDMA)中继系统,在考虑用户传输中断概率的同时,提出了满足不同用户最小服务质量(Qo S)需求和比例公平性约束条件下的中继选择、子载波分配和功率分配的联合优化问题,建立了以最大化系统总容量为目标的优化模型。在此基础上以速率最大化为目标进行最佳中继选择,并通过动态子载波分配来满足用户的最小Qo S需求和比例公平性,最后采用拉格朗日乘子法来得到最优功率分配方案。仿真结果表明,此算法在降低用户中断概率的同时,提高了系统吞吐量并保证了用户速率的比例公平性。

This paper addresses joint relay selection, dynamic subcarrier allocation and power allocation in the presence of the outage probability, users＇ quality of service （QoS） requirement and proportional rate constraints,in orthogonal frequency division multiple access （0FDMA） relay systems with channel esti- mated error. A mathematical model for maximizing the sum rate is established. Moreover, in order to en- hance proportional fairness among users, this paper develops an optimal low complexity subcarrier assign- ment scheme to meet the minimum QoS requirement of each user firstly and allocates the excess subcarriers to maintain the proportional fairness. Simulation results show that the proposed algorithm improves the sys- tem performance significantly compared with the conventional schemes in terms of the outage probability, sum rate and fariness.