Variable step-size least-symbol-error-rate adaptive decision feedback turbo equalization for underwater channel

In this paper, the turbo principle is applied to the existing least symbols error rate(LSER) decision feedback equalization(DFE) for underwater channel. The performance of the DFE adaptive algorithms are aided by soft information delivered from the channel decoder. We introduce a variable step size scheme that takes soft information into account to get the more suitable step size which can reduce the impact of an unreliable fed-back symbol. The simulation results show that the proposed scheme obtains more than 2dB gain at the bit error rate level of 10
⁻⁵
, compared with existing method.