On the mean acquisition times of DS receiver code synchronization using matched filters and median filters in AWGN-channel and continuous/pulsed tone jamming
J. Iinatti, P. Leppänen · 2002
This paper introduces the analysis and simulation results of a DS spread spectrum system in which the principle of matched filter synchronization for acquisition of code synchronization is used. Mean acquisition time approximations of coherent matched filter synchronization in AWGN-channel, continuous and pulsed tone jamming, when complementary codes are used as the spreading codes, are indicated. The idea of using median type filtering as an aiding device for the matched filter is tested in those situations. It is shown that the performance degradation in AWGN-channel is not catastrophic due to use of the median filter. Continuous and pulsed tone jamming can have a very dramatic influence on mean acquisition time if the imbalances of the codes have large values. The influence of continuous tone jamming can be totally eliminated by using a median filter. Pulsed tone jamming can be eliminated almost totally, if jamming is pulsed so that it is on during some whole code periods. Simulations show that the jamming can be eliminated even if the jamming is pulsed in a way that it is on during some chips within every code period.>