大规模天线系统中MRC解码法的性能分析

Abstract

研究基于大规模天线上行系统，对接收端采用最大比合并(MRC)解码法的成对错误概率(PEP)进行了分析。假定信道慢平坦衰落，基站已知信道状态信息。第一，介绍了MRC解码器的解码方法；第二，基于此方法，推导了系统的PEP公式；第三，针对两种不同情况推导出PEP的渐近趋势。分析表明：1) 当天线数固定时，信噪比趋于无穷大所得到的PEP不为零；2) 当信噪比固定时，天线数趋于无穷大时PEP降为零。最后，讨论了能量尺度律(power scale law)。数值仿真证实了上述结论的正确性。Based on a massive multiple-input, multiple-output (MIMO) uplink system, the pair-wise error probability (PEP) of the maximal ratio combining (MRC) decoder on the receiver is analyzed. The channel is assumed to be slow flat fading, and the base station (BS) knows the instant channel state information. Firstly, the MRC decoder is defined for the system. Secondly, a formula calculating the PEP of the system with the decoder is derived. Thirdly, asymptotic analyses of the PEP based on two different situations are given. These analyses reveal facts: 1) The PEP cannot go to zero even when signal-to-noise (SNR) goes to infinity; 2) The PEP goes to zero when the number of antennas at BS is increased to infinity and SNR is fixed. Finally, power scale law on PEP is discussed. Numerical simulations firm the above conclusions.