A Reed-Solomon coded DS-CDMA system using noncoherent M-ary orthogonal modulation over multipath fading channels

Abstract

Abstract-The performance of Reed-Solomon (RS) coded direct-sequence code division multiple-access (DS-CDMA) systems using noncoherent -ary orthogonal modulation is investigated over multipath Rayleigh fading channels. Diversity reception techniques with equal gain combining (EGC) or selection combining (SC) are invoked and the related performance is evaluated for both uncoded and coded DS-CDMA systems. "Errors-and-erasures" decoding is considered, where the erasures are based on Viterbi's so-called ratio threshold test (RTT). The probability density functions (PDF) of the ratio associated with the RTT conditioned on both the correct detection and erroneous detection of the -ary signals are derived. These PDFs are then used for computing the codeword decoding error probability of the RS coded DS-CDMA system using "errors-and-erasures" decoding. Furthermore, the performance of the "errors-and-erasures" decoding technique employing the RTT is compared to that of "error-correction-only" decoding refraining from using side-information over multipath Rayleigh fading channels. As expected, the numerical results show that when using "errors-and-erasures" decoding, RS codes of a given code rate can achieve a higher coding gain than without erasure information.Index Terms-Direct sequence code division multiple-access, error-correction-only decoding, errors-and-erasures decoding, noncoherent -ary orthogonal signaling, ratio threshold test, Reed-Solomon codes.

Multipath Fading Effects on Uncoded and Coded Multiple Frequency Shift Keying Performance in Mobile Wireless Communications

“…One way to compensate for BER degradation in MFSK modulation due to channel fading is by using coding process. This paper will analyze the block coding (BC) for error control used in MFSK receivers such as interleaving, Reed Solomon BC [11][12][13], and Alamouti space-time block coding (STBC) [14]. Reed Solomon BC that will be used in conjunction with MFSK is non-binary, linear cyclic code RS (n, k).…”