Linear zero forcing (ZF) precoding can obtain near-optimal performance as the number of base station (BS) antennas increases, but involve complex matrix inversion calculations whose computational complexity is cubic with respect to the number of user equips (UEs) in massive multiple-input multiple-output (MIMO) systems. In this paper, a low-complexity modified successive over-relaxation-based ZF (MSOR-ZF) linear precoding is proposed, in which complicated matrix inversion is directly avoided through the use of MSOR iteration. Moreover, to further increase the convergence rate, the proposed MSOR-ZF precoding exploits the diagonal dominant property of the matrix instead of the original zero vector solution to achieve a satisfactory performance with a reduced iteration number. The proposed precoding is superior in convergence rate and reduces the computational complexity by approximately one order of magnitude, which is indicated by theoretical analysis. Simulation results demonstrate that the proposed precoding can achieve better achievable sum-rate and bit-error-ratio (BER) performance than some existing iterative-based precoding schemes with lower complexity.

线性零强迫（ZF）预编码可以随着基站（BS）天线数量的增加而获得接近最佳的性能，但是涉及复杂的矩阵求逆计算，其计算复杂度相对于大量用户设备（UE）的数量而言是三次的输入多输出（MIMO）系统。本文提出了一种基于低复杂度的改进的基于连续超松弛的ZF（MSOR-ZF）线性预编码，其中通过使用MSOR迭代直接避免了复杂的矩阵求逆。此外，为了进一步提高收敛速度，提出的MSOR-ZF预编码利用矩阵的对角线主导特性代替原始的零向量解决方案，从而以降低的迭代次数获得令人满意的性能。所提出的预编码在收敛速度方面优越，并且将计算复杂度降低了大约一个数量级，这在理论分析中得到了证明。仿真结果表明，与一些现有的基于迭代的，具有较低复杂度的预编码方案相比，所提出的预编码可以实现更好的总和率和误码率（BER）性能。