协作分集系统中基于注水算法的功率分配方案研究

Research on Power Allocation Scheme Based on Water-filling Algorithm in Cooperative Diversity System

为了提高协作分集系统的信道容量,该文在多中继节点协作背景下提出了基于注水算法的中继节点功率分配方案。首先,对空时矩阵的列序号提出了一种新的映射方案,该方案能够提升中继节点发射信号间的正交性。对于采用线性正交解码算法的GABBA码,列序号重新排布后能够降低误码率。然后,通过对接收信噪比与中继节点发射功率的分析,针对信道容量最大化问题提出了一种应用注水算法的两步求解方案。该文对瑞利平坦慢衰落信道下采用GABBA码的协作分集系统进行仿真,仿真结果表明,与中继节点发射功率均分方案相比,该文提出的功率分配方案能够提升系统抗误码性能,达到满分集增益t rN′N。该文提出的方案在不同的仿真条件下对信道容量均有提升,并且信道容量与2min{t,r}logN N′M成正比。

In order to increase the capacity of cooperative diversity system, a novel power allocation scheme based on water-filling algorithm is proposed under the background of multiple-relay cooperation. First, a novel node index mapping scheme is provided to enhance the orthogonality of signal transmitted by relay nodes. For the GABBA codes applying linear orthogonal decoding, the proposed scheme can decrease the symbol error rate. Then, by analyzing the relationship between SNR and the power allocated by relay nodes, a two-step solution with water-filling algorithm is proposed to solve the optimization problem. Simulation results indicate that, the scheme based on water-filling algorithm can obtain better performance on SER compared with equal allocation scheme. In addition, both the two schemes can obtain the same diversity order Nt x Nr , which is same as MIMO scenario. Furthermore, this scheme can achieve higher capacity for different antenna-deployment. The capacity of cooperative diversity system is proportional to min {Nt, Nr} ×log2 M.