短波环境中频域差分解调器误码率性能分析

Performance analysis of frequency domain differential demodulator over fading HF channels

在短波信道条件下,分析了正交频分复用系统中标准的频域差分解调和相位纠正的频域差分解调的误码率性能,并给出了频域差分解调的OFDM系统子载波数N的优化值。理论分析与仿真结果表明:对于典型短波信道,多径延迟扩展对系统优化的频域差分系统的误码率性能影响不大;对于快速衰落的短波信道,系统优化的频域差分系统仍然遭受多径延迟扩展和时变干扰的影响且有较大的误码平台。此外,在快速衰落短波信道环境下相位纠正的频域差分解调器性能优于常规的差分解调器性能。

In high frequency （HF） fading channels, the bit error rate （BER） performance of standard frequency domain differential demodulation （FDDD） and phase corrected FDDD in orthogonal frequency division multiplexing （OFDM） systems is analyzed and the optimized number of subcarriers is given. Analytic evaluation and simulation results show that delay spread has little effects on performance of the optimized FDDD systems in typical HF channel. However, the optimized FDDD systems suffer from the effects of delay spread and time-variant interference at the same time, and has big error floor in fast fading HF channel. Also, the performance of phase corrected FDDD systems outperforms the conventional differential demodulator over fast fading HF channel.