为减少射频链路开销的同时满足系统高容量需求，提出使用有限射频链路的毫米波混合数模预编码，以实现硬件成本和系统性能的折中。在多用户毫米波MIMO系统下，首次提出基于射频链路选择的高能效混合预编码算法。首先利用预设的模拟预编码码本将原三元耦合变量联合优化问题转变为稀疏数字预编码优化问题。由于问题非凸非线性，接着利用顺序凸近似与分数规划理论，设计一种迭代求解算法。仿真结果表明所提算法在能效上十分逼近于穷举法并显著优于其他算法。
In order to reduce the radio frequency (RF) chains cost and satisfy the high capacity demand for communication systems, millimeter wave hybrid precoding with limited RF chains is proposed to make a tradeoff between hardware cost and system performance. In this work, we study the energy-efficient hybrid precoding design problem based on RF chains selection for a millimeter wave multi-user multiple-input multiple-output (MIMO) system. First, we use the predesigned analog precoding codebook to reformulate the original problem as a sparse digital precoding problem. Then we solve it iteratively using successive convex approximation (SCA) method combined with fractional programming method. The simulation results show that our proposed algorithm gives the performance very close to that of the exhaustive search and better than those of the other existed algorithms.
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