Improved MC-CDMA reception employing two-dimensional decision-feedback pilot and data symbol correction

Abstract

An algorithm is presented that recovers, to a large degree, the performance degradation due to channel estimation and equalization errors in a multi-carrier code division multiple access (MC-CDMA) system. The algorithm uses the two-dimensional structure of the MC-CDMA frame to estimate the equalization error. It contains two steps that can be applied independently from each other. In the first step, the pilot symbols are corrected and channel estimation and equalization are redone for the received data symbol samples. In the second step, a possible remaining mismatch on the equalized data symbol samples is 're-equalized' and new symbol decisions on the 're-equalized' signal are made. It is shown that the algorithm is able to improve the performance in additive white Gaussian noise (AWGN) and fading channels with and without channel coding. On a frequency-selective fading channel and with standard R/sub cc/=1/2 convolutional coding, a performance improvement of approximately 4.75 dB is possible at a BER of 10/sup -6/.