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摘要:
超奈奎斯特(FTN)传输技术是一种高频谱效率的信号传输方式。针对FTN信号存在的码间串扰，基于软输出维特比算法(SOVA)提出FTN信号的低复杂度接收算法。根据幸存路径和竞争路径的判决结果，动态地调整每个时刻回溯过程的比较次数，降低比较次数平均值。在实际应用中，根据不影响误码性能的统计经验值直接截短回溯路径的长度。直接截短回溯深度算法可在不恶化误码率(BER)的前提下，降低比较运算次数2/3，同时减少回溯过程所需寄存器资源和延时50%以上。
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关键词:
- 超奈奎斯特(FTN)传输信号 /
- 低复杂度 /
- 回溯过程 /
- 比较次数 /
- 寄存器资源
Abstract:Faster-than-Nyquist (FTN) signaling is a transmission method with high bit density and inevitable inter-symbol interference. Based on soft output Viterbi algorithm (SOVA), a low complexity receiver for FTN was introduced. The number of comparison in the backtracking process was adjusted by the result of survivor path and competitive path, and was reduced during the process. In application, a fixed backtracking length was searched and defined by statistical value, which was shorter than that in SOVA. The presented method reduces the complexity and time delay in the FTN signal detector. Without deteriorating bit error rate (BER), the number of comparison operations is reduced by 2/3, the number of registers is reduced by more than 50%, and the system delay is reduced by more than 50%.
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图 1 FTN信号在不同信噪比条件下modified-SOVA-1算法回溯比较次数分布
Figure 1. Backtracking comparison number distribution for FTNsignal under different SNRs by modified-SOVA-1 algorithm
图 3 FTN信号在不同回溯路径长度/比较次数下的误码率
Figure 3. BERs for FTN signal under different backtracking lengths/numbers of comparison
表 1 SNR=3 dB时, 不同参数τ的FTN信号比较次数和回溯深度分布
Table 1. Backtracking comparison number and depth distribution for FTN signal with coefficient τ when SNR=3 dB
K τ=9/10 τ=5/6 δ′ δ′占比/% δ′ δ′占比/% 5 8 89.43 8 81.57 6 9 2.76 9 4.86 7 10 2.66 10 4.48 8 11 2.36 11 3.73 9 12 2.03 12 2.73 10 13 0.30 13 0.95 11 14 0.20 14 0.65 12 15 0.12 15 0.43 13 16 0.08 16 0.25 14 17 0.02 17 0.16 15 18 0.01 18 0.09 16 19 0.01 19 0.05 17 20 0.01 20 0.03 18 21 0.02 19 22 0.01 20 23 0.01 
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表 2 SOVA和modified-SOVA-2算法的回溯比较次数
Table 2. Backtracking comparison number in SOVA and modified-SOVA-2 algorithms
算法 回溯比较次数 SOVA LSδ modified-SOVA-2 LS 
下载: 导出CSV
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