车联网中车-车通信系统在n-Rayleigh信道下的性能分析

摘要

The average symbol error probability (ASEP) and channel capacity of vehicle-to-vehicle communication system employing election combining (SC) receiving under n-Rayleigh fading channels is investigated in this paper. Based on the integral approach, the exact form expressions of the average symbol error probability are derived for M-ary phase shift keying (MPSK) and M-ary pulse amplitude modulation (MPAM). The exact form expressions of ergodic capacity are also presented. Then the ASEP and channel capacity performance under different conditions is respectively evaluated through numerical simulations. The numerical simulations results coincide with the theoretical results well, and the accuracy of the analytical results is veriifed. Simulation results show that: the ASEP and channel capacity performance can be improved with the increase of the number of diversity branches, when SNR=16dB, the diversity branches L=1, the ASEP with QPSK is 7×10-2, the channel capacity is 4bps/Hz; the diversity branches L=2, the ASEP with QPSK is 1×10-2, the channel capacity is 5.1bps/Hz; the diversity branches L=3, the ASEP with QPSK is 2×10-3, the channel capacity is 5.8bps/Hz.%文章在n-Rayleigh衰落信道下，研究了使用选择合并（electioncombining，SC）接收的车—车通信系统的平均符号误码率（average symbol error probability，ASEP）和信道容量性能。文章基于积分法，分别推导了车—车通信系统采用M进制相移键控（M-ary phase shift keying，MPSK）和M进制脉冲幅度调制（M-ary pulse amplitude modulation，MPAM）的平均符号误码率的精确表达式和信道容量的精确表达式。然后在不同系统条件下，分别对平均符号误码率和信道容量性能做了数值仿真，理论分析结果与仿真结果相吻合，验证了理论分析结果的正确性。仿真结果表明，随着分集支路数的增加，系统的ASEP和信道容量性能得到了很好的改善，当使用QPSK调制信噪比为16dB时，分集支路数L=1，系统的误码率是7×10-2，信道容量是4bps/Hz；分集支路数L=2，系统的误码率是1×10-2，信道容量是5.1bps/Hz；分集支路数L=3，系统的误码率是2×10-3，信道容量是5.8bps/Hz。