'Errors-and-erasures' decoding performance of RS coded DS-CDMA using M-ary orthogonal signalling

Abstract

In this contribution we investigate the performance of RS coded DS-CDMA using M-ary orthogonal signalling over multipath Rayleigh fading channels. 'Errors-and-erasures (EAE)' RS decoding is considered, where erasures are declared based on the joint maximum output and ratio threshold test (MOR-TT). Two classes of diversity reception techniques suitable for noncoherent M-ary detection are invoked, namely either equal gain combining (EGC) or selection combining (SC) and their related performance is evaluated for both uncoded and coded DS-CDMA systems. The performance of the proposed MOR-TT technique is compared to that of the ratio threshold test (RTT) and the output threshold test (OTT), as well as that of 'error-correction-only (ECO)' decoding. The numerical results show that when using EAE decoding, RS codes of a given code rate are capable of achieving a significantly higher coding gain than without erasure information. Furthermore, the MOR-TT technique outperforms both the RTT and the OTT techniques.