DIGITAL COMMUNICATIONS OVER SATELLITE CHANNELS

In this dissertation, the problem of digital data transmission over bandlimited nonlinear channels in the presence of intersymbol interference, white Gaussian noise in the uplink and downlink paths, is considered.; The satellite transponder is assumed to be either of the hard-limiter or soft-limiter type.; A maximum likelihood receiver is developed to detect BPSK signals transmitted over a satellite channel.; It is shown that for wideband channels, the receiver structure corresponds to the one-sample test for both hardlimiting and softlimiting transponders. As part of the derivation of optimum receivers, a square law structure is obtained for the softlimiter case with intersymbol interference. The analysis is then repeated for the QPSK system with similar results. Also, the problem of in-bank carrier interference in the presence of uplink and downlink noise is considered by deriving the likelihood receiver for this case. It is shown that the optimum receiver is of the one-sample type for the wide band channel and of the square law type for the band limited case.; Next, a mode of operation inroling partial response signaling (PRS) is introduced. A frequency domain receiver equalizer is derived for receiving PRS transmitted over satellite channels. Specifically, design of frequency domain receivers for PRS over satellite transponders with timing jitter suppression capabilities is developed. Finally, the problem of recursive estimation is considered which leads to the derivation of the minimum mean-square estimator for the BPSK transmission over a nonlinear bandlimited channels using linear and nonlinear estimators. The estimation process takes into account the effect of future data symbols leading to a clear advantage over a decision feedback receiver structure.