Decision feedback equalization for low power underwater communication system

In this paper, a decision feedback equalizer(DFE) is applied to the PSSK(Phase Shift Silence Keying) and PSPM (Phase Shift Pulse-position Modulation) for low-power communication in underwater sensor network. All of the M-ary PSK(Phase Shift Keying) symbol of PSSK that was proposed for low power communication in WBAN(Wireless Body Area Network) has the silence duration for a half period of symbol. Similarly, PSPM is also a kind of PSK modulation which is combined with PPM(Pulse Position Modulation). The bandwidth efficiency of PSPM is lower than conventional PSK and PSSK, but the power efficiency better than those methods. However, the problem of PSSK/PSPM is so erratic to find PSK signal duration because of the delay spreads. If the decision for the signal position is wrong, then the error probability of PSSK/PSPM is significantly increased. For this reason, we applied to these modulations the DFE and compared the BER performances about QPSK, PSSK and PSPM data which is acquired from the sea trials.