Improved forward link error correction for CDMA systems with space time transmit diversity

The channel code decoder in a CDMA mobile performs channel state estimation to determine the reliability of each received encoded symbol. This reliability information is typically an estimate of received signal envelope and interference plus noise variance. Most papers that investigate CDMA forward link channel code performance assume that all interference and noise can be modeled as a single, stationary Gaussian process. This assumption leads to inaccurate channel state estimates since in-cell interference is non-stationary on the CDMA forward link. This paper presents a channel state estimation procedure for single antenna and Space Time Transmit Diversity (STTD) transmission that accounts for non-stationary in-cell interference. Simulations are used to illustrate how this scheme improves convolutional and turbo code performance.