Hybrid Channel Coding for Error-Sensitive Class on DS-CDMA Air Interface

A DS-CDMA system with QPSK modulation and a RAKE receiver is modeled and simulated. A mathematical description of the DS-CDMA system is provided on uplink and downlink. For a multipath channel environment, modeling techniques for AWGN and Rayleigh fading are illustrated. Comparisons are made concerning the performance of CDMA systems with hybrid data rates.

The thesis proposes a technique for hybrid channel coding for ARQ (Automatic-Repeat-reQuest) protocol and FEC (Forward Error Correction) scheme that can reduce the error rate significantly. Each of ARQ protocol and FEC scheme gives rise to long latency and significant complexity, respectively, for obtaining the required QoS (Quality of Service). This thesis shows using theoretical analysis and computer simulations that synergistic effects are possible by using both an ARQ protocol and a FEC scheme.