Coordinate-by-coordinate interleaved trellis coded QPSK with T-algorithm on Rayleigh fading channels

We propose a coordinate-by-coordinate interleaved trellis coded QPSK with the T-algorithm. A rate 1/2 convolutional code with constraint lengths of 7 and 15 are evaluated on Rayleigh fading channels in terms of the bit error rate (BER) by an analysis and a computer simulation. As the effective code length (ECL) is equal to the code constraint length for the case of a QPSK system, the proposed system achieves a satisfactory BER performance even in the situation where no channel state information (CSI) is available at the decoder. Further, in order to reduce the decoding complexity, we employ the T-algorithm. It is shown that as the T-algorithm can track the fluctuating gains introduced by the fading channel, we can achieve a satisfactory BER performance with 0.01% of the decoding complexity of the Viterbi algorithm