单用户对双向中继系统中基于梯度下降的最大化和速率功率分配方案∗

摘要

In single-pair two-way relay system,a new power allocation(PA)of maximizing sum-rate based on gradient descent method is proposed. Under the constraint of transmit power sum,with the aim of maximizing the sum-rate,we obtain the locally-optimal weighted matrix of relay station and PA policy by alternative iteration between the weighted matrix of relay station and PA policy. The simulations show that,compared to equal PA(EPA),the proposed PA achieves a 2.5 dB~3 dB signal-to-noise-ratio( SNR) gain at the bit-error-ratio 10-2;additionally,in the region of medi-um and high SNRs,the proposed PA indicates a sum-rate gain of 0.3 (bit/s)/Hz~0.5 (bit/s)/Hz over EPA.%针对单用户对双向中继系统中的功率分配问题，提出了一种基于梯度下降法的功率分配方案。该方案在总功率约束的条件下，以最大化和速率为目标函数，通过对中继波束成形矩阵和功率分配矩阵的反复迭代，求解出局部最优的功率分配和中继波束成形矩阵。仿真结果表明：提出方案的误码性能相比于等功率分配有明显提高，在误码率为10-2时，可获得2.5 dB~3 dB的信噪比增益；同时，在中高信噪比下，相比于等功率分配，该方案可获得0.3( bit/s)/Hz~0.5( bit/s)/Hz的和速率增益。