两径衰落短波信道下的改进型双向判决反馈均衡器

将双向判决反馈均衡器(bidirectional decision-feedback equalizer, BiDFE) 应用于两径衰落短波信道，提出了一种低复杂度的改进型BiDFE 方案. 针对两径信道的特殊性质，对均衡器的系数进行优化设置，在此基础上对BiDFE 的正向DFE和反向DFE进行最大比合并. 理论分析和仿真结果表明，改进型BiDFE 能够使正向DFE和反向DFE的输出完全消除码间干扰，且输出信噪比为两条支路的信噪比之和. 在两径衰落短波信道下，改进型BiDFE 的误码率性能优于传统DFE和双向任选DFE(bidirectional arbitrated DFE, BAD)，且计算复杂度低于BAD.

Modified Bidirectional Decision-Feedback Equalizer for Two-Ray Fading HF Channels

In this paper, we consider the use of a bidirectional decision-feedback equalizer (BiDFE) in two-ray fading HF channels. A low-complexity modified BiDFE using the properties of these channels is proposed. Coefficients of the equalizer are optimized, and the outputs of forward DFE and time-reversal DFE are combined using maximal ratio combining (MRC) rules. Theoretical analysis and computer simulations show that the proposed scheme completely cancels inter-symbol interference (ISI) between the two streams so that signal-tonoise ratio (SNR) is the sum of SNRs of the two streams. The performance of modified BiDFE is superior to conventional DFE and bidirectional arbitrated DFE (BAD), while the computation complexity is lower than BAD.