Ucan-decoders in partial response channels

Abstract

In order to improve the bandwidth efficiency and error performance Ucan-decoders, employing a new partial response channel model for M-PSK schemes, are introduced . The Ucan-decoder is composed of k-unit precoders cascaded with a PSK modulator and (1/spl mnplus/D) PRS channel model. In this scheme only k-unit memory of the precoder defines the state number of the decoder and the author denotes k as the "effective memory unit". As an example, Ucan (k=1,2,3) decoders employing (k=1,2,3) effective memory units are investigated for (M=2,4,8) PSK modulations respectively. In an AWGN environment, analytical upper bound curves of the proposed schemes are derived. The error performance of the Ucan-decoders are better than the related systems at all signal to noise ratios. An interesting result is also obtained in a colored noise environment for a correlation coefficient less than zero. It is shown that the Ucan-decoders perform better in colored noise compared to AWGN at all signal to noise ratios.