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

An adaptive reduced-state sequence estimation (RSSE) receiver based on per-survivor processing (PSP) in conjunction with a local decision feedback equalizer (DFE) for the EDGE system with 8PSK modulation is proposed in this paper. A prefilter 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 RSSEPSP 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. Keywordsreduced-state sequence estimation; per-survivor processin; decision feedback equalizer; EDGE.