The present study investigates the problem of bit error rate minimization in multi-input-multi-output orthogonal frequency-division multiplexing amplify-and-forward relay systems. It is supposed that channels are frequency selective fading and under a total power constraint. In the multi-antenna transmitter, an independent symbol sequence is transmitted from each antenna. Zero forcing beamforming is performed in the reception and transmission of the relay to cancel out the inter-antenna interference. A power allocation and subchannel pairing scheme is considered as the optimization method. The goal of the optimization problem is to achieve the best bit error rate performance by applying a joint power allocation and subchannel pairing approach for all antennas. To deal with subchannel pairing, at first, we formulate it as a linear assignment problem and then Jonker-Volgenant algorithm is used to solve this problem. The joint scheme is compared with separate power allocation and subchannel pairing for each antenna as the main target. It is found that the joint scheme is superior to the separate method. Simulation results show that the proposed inter-antenna power allocation and subchannel pairing scheme can improve bit error rate and mean square error dramatically compared with separate subchannel pairing and power allocation at the cost of a little increase in complexity.

中文翻译：

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用于MIMO-OFDM AF中继系统中BER最小化的功率分配和子信道配对

本研究研究了多输入多输出正交频分复用放大转发系统中的误码率最小化问题。假设信道是频率选择性衰落的，并且处于总功率约束之下。在多天线发射机中，从每个天线发送一个独立的符号序列。在中继器的接收和发送中执行零强制波束成形，以消除天线间干扰。功率分配和子信道配对方案被认为是优化方法。优化问题的目的是通过对所有天线应用联合功率分配和子信道配对方法来获得最佳的误码率性能。首先要处理子频道配对 我们将其表述为线性分配问题，然后使用Jonker-Volgenant算法解决该问题。将联合方案与每个天线作为主要目标的单独功率分配和子信道配对进行比较。发现联合方案优于单独方法。仿真结果表明，与单独的子信道配对和功率分配相比，所提出的天线间功率分配和子信道配对方案可以显着提高误码率和均方误差，但代价是稍微增加了复杂度。