认知无线电中的一种信道估计方法

A channel estimation method in cognitive radio

认知无线电系统能否充分发挥其优势在很大程度上取决于信道估计的准确性和实时性。将基于新型时域内插的初始估计和EM跟踪应用于认知无线电系统,同时引入小波包对初始估计进行消噪处理,提出了一种新型的半盲信道估计方法。理论分析和仿真表明,该方法较好地解决了由于主用户存在造成的导频分布不均匀,保证了天线之间导频符号的相关性,且由于采用EM信道跟踪和小波包去噪进一步节省了频谱资源、提高了估计准确性。该方法可满足认知无线电信道估计实时性和准确性要求,具有较大的实际应用价值。

To a large extent, the display of advantages in cognitive radio system depends on the accuracy and real-time performance of channel estimation. The initial estimation based on a new time-domain interpolation and EM tracking were applied to cognitive radio system, and wavelet packet was used to eliminate the noise effect. A new semi-blind channel estimation algorithm was proposed. Theoretical analysis and simulation results show that this algorithm solves the problem that the distribution of the pilots is not equally-spaced due to the existence of primary users, ensures the correlation of the pilots between anten- nae, saves the spectrum resource and improves the estimation accuracy owing to wavelet packet. Therefore, this algorithm can satisfy the demand for real time and accuracy of channel estimation in cognitive radio and is valuable in practice.