AWGN信道EBPSK系统解调性能分析

为获得加性高斯白噪声(AWGN)信道中EBPSK系统的最佳解调性能,对抽样判决和积分判决下的误比特率公式进行推导.首先,解调器基于特殊的冲击滤波器,推导得出AWGN通过冲击滤波器后服从的分布函数;然后,利用EBPSK调制信号通过该滤波器的全响应公式,推导得到抽样判决条件下调制信号0和1的概率密度函数分别服从广义瑞利分布和改进后的广义瑞利分布,由此得出积分判决条件下调制信号0和1的概率密度函数,并仿真比较了抽样判决和积分判决的误比特率以及理论误比特率公式和仿真误比特率之间的差异.结果表明:推导得出的误比特率公式(抽样判决、积分判决)与仿真结果相差远小于1 dB,且积分判决与抽样判决相比误比特率性能提升大于1 dB.

Performance of EBPSK demodulator in AWGN channel

In order to obtain the best performance of EBPSK(extended binary phase shift keying) demodulation in AWGN(added white Gaussian noise) channel,the bit error rate(BER) formulas in the conditions of sampling decision and integration decision are derived.First,as in demodulator an impacting filter is introduced and the distribution function of the noise through the impact filter is derived.Then,using the response formula of EBPSK modulation signal through the impulse filter,it is obtained that under sampling decision condition the probabilities of transmitting signal 0 and transmitting signal 1 are subject to Rice distribution and modified Rice distribution respectively. Therefore the probabilities of transmitting signal 0 and transmitting signal 1 in the integration decision condition are deduced,and the bit error rates(BER) under both conditions are compared,furthermore, the theoretical results and the simulation results are compared. It is shown that the BER formula result deduced for sampling decision and integration decision is similar to simulation results.The difference is less than 1 dB.And the BER performance of integration decision is more than 1 dB better than that of sampling decision.