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In this paper,a novel dual-metric,the maximum and minimum Squared Euclidean Distance Increment (SEDI) brought by changing the hard decision symbol,is introduced to measure the reli-ability of the received M-ary Phase Shift Keying (MPSK) symbols over a Rayleigh fading channel. Based on the dual-metric,a Chase-type soft decoding algorithm,which is called erased-Chase algorithm,is developed for Reed-Solomon (RS) coded MPSK schemes. The proposed algorithm treats the unre-liable symbols with small maximum SEDI as erasures,and tests the non-erased unreliable symbols with small minimum SEDI as the Chase-2 algorithm does. By introducing optimality test into the decoding procedure,much more reduction in the decoding complexity can be achieved. Simulation results of the RS(63,42,22)-coded 8-PSK scheme over a Rayleigh fading channel show that the proposed algorithm provides a very efficient tradeoff between the decoding complexity and the error performance. Finally,an adaptive scheme for the number of erasures is introduced into the decoding algorithm.
In this paper, a novel dual-metric, the maximum and minimum Squared Euclidean Distance Increment (SEDI) brought by changing the hard decision symbol, is introduced to measure the reli-ability of the received M-ary Phase Shift Keying (MPSK) symbols Based on the dual-metric, a Chase-type soft decoding algorithm, which is called erased-Chase algorithm, is developed for Reed-Solomon (RS) coded MPSK schemes. The proposed algorithm treats the unre- liable symbols with small maximum SEDI as erasures, and tests the non-erased unreliable symbols with small minimum SEDI as the Chase-2 algorithm does. By introducing optimality test into the decoding procedure, much more reduction in the decoding complexity can be achieved. Simulation results of the RS (63,42,22) -coded 8-PSK scheme over a Rayleigh fading channel show that the proposed algorithm provides a very efficient tradeoff between the decoding complexity and the error performance. Finally, an adaptive scheme for the numb er of erasures is introduced into the decoding algorithm.