一种适于小波包多载波系统导频信道估计的方法

提出了一种适于小波包多载波系统信道估计的导频插入方法．该方法结合小波包多载波系统树型结构的分解特性以及不同频率对相干时间的影响，将子载波在树型结构的基础上分成若干个组，并结合等差原理，引入时域不等间隔的导频模式，实现导频的合理分配．在上述方法中，高频部分插入了相对较多的导频，使得总的导频数减少的同时，能够更好地估计多普勒频移的影响．仿真结果表明，在载波调制过程中，采用不等间隔导频模式与传统的等间隔块状导频模式相比，当导频个数减少14％，信噪比为20dB时，误比特率降低了19．6％；并且不论多普勒频移如何变化，系统总能在多径瑞利衰落信道中保持良好的性能．

A Method of Pilot Channel Estimation Scheme for Orthogonal Wavelet Packet Modulation System

A method of pilot arrangement for orthogonal wavelet packet modulation （OWPM） system was proposed in this paper. Based on the characteristics of tree structure decomposition for OWPM system and the influence on the coherent time caused by frequency-domain,this proposed method divided sub-carriers into groups with unequal pilot insertion interval in time-domain based on the tree structure, and employed the arithmetic theory to realize the pilot arrangement optimally. In this method,more pilots were inserted into the higher frequency domain,so the total number of pilots was reduced,and much more exact estimation of effects of Doppler spread was achieved. The simulation results indicated that in the case of fre- quency modulation,the performance was increased by 19.6% when the number of pilots decreased by 14% and signal to noise ratio （SNR）equal to 20 dB ;and also,for different Doppler spread values,the method proposed always performed excellently in the multi-path Rayleigh fading channel.