Based on the analysis of shallow acoustic water channel, the article discuss its multipath time delay, and put forward an adaptive model and the method of underwater adaptive simulation to lessen the effect from multipathing.

For LFM (linear frequency modulation) pulse sonar, the method, based on modified time frequency correlation, for joint estimation of Doppler frequency and multipath time delay of overlapping echoes, can, in our opinion, be improved.

In this paper, based on the space-time two dimensional MUSIC algorithm, a new method utilizing the received information of user instead of pilot signal during the period of normal communication is proposed to estimate DOA and multipath time delay of the signal of interesting (SOI) user in CDMA system.

By using the characteristics of PN code and the maximum-likelihood method, the channel im pulse response vector can be estimated, then all of the multipath delays and attenuation weights can be obtained.

Based on Watterson model,establishs a Simulink HF audio channel model,which can consider HF characters well such as multipath delay,Doppler spread and so on.

Algorithm for modulation recognition in a time-variant multipath channel environment;

This thesis mainly deals with the intercarrier interference (ICI) of the OFDM systems caused by time-variant multipath channels.

Algorithm for classification of MPSK signals in multipath channel environments;

Blind multiuser detection based on equal gain combining in multipath channel;

DS/SS navigational signal tracking performance in the multipath channel;