An adaptive RSSE-PSP receiver with a pre-filter for EDGE systems

Abstract

An adaptive reduced-state sequence estimation (RSSE) receiver based on per-survivor processing (PS) in conjunction with a local decision feedback equalizer (DFE) for the EDGE system with 8PSK modulation is proposed in this paper. A pre-filter prior to the RSSE-PSP is exploited to reshape the channel impulse response (CIR) to have approximately a minimum phase property. The pre-filter settings are computed indirectly by estimating the CIR from the midamble with the least squares algorithm and then applying the minimum-mean square error (MMSE) criterion to reshape the estimated CIR. The proposed scheme handles the first part of the sampled CIR by the RSSE-PSP and the rest by the local DFE, which utilizes the decision per survivor mechanism for reducing the error propagation and complexity reduction. A good trade-off between the performance and complexity could be achieved by retaining the RSSE-PSP for good performance and local DFE for intersymbol interference cancellation. Computer simulations indicate that the RSSE-PSP with a pre-filter works well in ISI channels with a lower computation burden.