为利用高速无线通信时信道的稀疏多径传播特性, 改善传统单载波分块传输(SCBT)信道估计方法的性能, 提出了一种阈值判决引导的稀疏信道估计方法。该方法通过导频进行初始最小二乘信道估计, 利用获取的信道估计值设置判决阈值。然后, 将幅值低于判决阈值的信道抽头强制置零, 仅保留幅度值大于判决阈值的信道抽头估计值, 从而有效地改善单载波分块传输系统的稀疏信道估计性能。基于COST 207典型乡村信道模型进行了仿真实验, 结果表明: 阈值判决引导的稀疏信道估计方法的实验结果最接近于信道参数已知时的误比特率性能; 在信噪比为20 dB条件下, 新方法的误比特率可达到5×10-4, 而最小二乘算法只能达到3×10-2。该方法改善了SCBT系统的稀疏信道估计精度与复杂度, 得到的结果验证了提出方法的有效性。

A threshold decision directed sparse channel estimation (TDDSCE) method was proposed for a Single Carrier Block Transmission(SCBT) system, which can take advantage of the sparsity inherent in high rate wireless communication channels, and improve the channel estimation accuracy. Firstly, a pilot sequence was used to perform a least square (LS) channel estimation, then a decision threshold was derived by obtained channel estimated values. The channel taps whose values were smaller than the decision threshold were forced to be zeros, only the channel taps whose values were above the decision threshold were reserved, so that the sparse channel estimation accuracy was greatly improved. A simulation experiment was carried out based on a COST 207 rural area channel profile, and the results show that the performance of proposed method is most close to that of the known channel case, and its bit error rate (BER) reaches 5×10-4 when the signal to noise ratio is 20 dB. However, the traditional LS channel estimation method only achieves the BER of 3×10-2. The method improves the sparse channel estimation accuracy and reduces the complexity of the SCBT system, and its feasibility is verified by obtained results.