Comparison of very low rate coding methods for CDMA radio communications system

The paper considers coherent transmission of very low rate coded signals in DS-CDMA radio communications system. The coding methods discussed are orthogonal convolutional coding and biorthogonal convolutional coding. For these codes, bit error rate (BER) bounds are determined in a white Gaussian noise channel environment. The performance of these schemes in a Rayleigh fading channel are discussed with simulation results. It is found that for the same code rate, biorthogonal convolutional coding gives a much better BER performance than the other scheme with slightly added complexity in the decoder