非线性失真环境下的天线功率分配算法

Power allocation algorithm for systems with nonlinear distortion

本文研究MIMO系统中,考虑功放的非线性限幅作用后,该如何在天线之间分配功率的问题。在这种情况下,采用传统的贪婪算法,信道增益小的天线上分配的功率可能很大,超过功放的线性范围,产生严重的非线性失真。不仅无法提高系统吞吐量,反而会导致吞吐量的恶化。通过对非线性失真环境下的系统吞吐量的分析,提出了一种改进的贪婪算法,综合考虑了无线信道引起的衰落和功放限幅引起的失真等因素,能够更加合理的分配天线功率。仿真结果也表明,新算法在信号功率较大的时候比传统的算法拥有更高的吞吐率。

This paper focuses on power allocation problems for MIMO systems with nonlinear distortion caused by Power Amplifier （PA）. For traditional Greedy Algorithm, power allocated to one antenna depends on the corresponding channel gain, which means extremely large power will be allocated on antennas with extremely low channel gain. In practical systems with PA, peak power of each antenna shall be limited to its linear region; otherwise serious signal distortion will be introduced and system performance will be degraded. In this paper, by analyzing the capacity of MIMO systems with nonlinear distortion, an improved greedy algorithm is proposed which can achieve a more accurate allocation between multiple transmit antennas. Simulation results also proves that the throughput of new algorithm is much higher than that of the traditional one when the total power constraint is high.