Performance of RS coded DS-CDMA using noncoherent M-ary orthogonal modulation over multipath fading channels

The performance of Reed-Solomon (RS) coded direct-sequence code division multiple-access (DS-CDMA) systems using noncoherent M-ary orthogonal modulation is investigated over multipath Rayleigh fading channels. Equal gain combining (EGC) diversity reception is invoked and the related performance is evaluated for both uncoded and RS-coded DS-CDMA systems. `Errors-and-erasures´ decoding is considered, where the erasures are based on Viterbi´s (1982) so-called ratio threshold test (RTT). The performance of the `errors-and-erasures´ decoding technique employing the RTT is compared to that of `error-correction-only´ decoding over multipath Rayleigh fading channels. The numerical results show that when using RTT-based `errors-and-erasures´ decoding, RS codes of a given code rate can achieve a higher coding gain than without erasure information