The Design of Adaptive SIMO Equalizer in the Time-varying Channel

In order to eliminate the serious inter symbol interference caused by multipath effect in the underwater acoustic channel, an adaptive Single Input Multiple Output (SIMO) decision feedback equalizer that works in a time varying channel is designed. Firstly, according to the characteristics of the underwater acoustic channel, a time varying channel model is established. Secondly, in order to improve the signal-to-noise rate of the received signal and to increase long distance transmission ability, the space diversity technique and adaptive decision feedback equalizer are effectively combined together. Moreover, to avoid phase rotation, the phase-locked loop is embedded in it, forming a kind of adaptive SIMO decision feedback equalizer with embedded phase-locked loop working in a time-varying channel. Finally, through the simulations and river and sea experiments, it is proved that the designed equalizer is feasible in time-varying channel. The results show that in time-varying channel, an adaptive SIMO decision feedback equalizer with embedded phase-locked loop improves the ability of the equalizer to suppress the multi-path effect, and it can also achieve a lower BER and decrease convergent error.