Block coded modulation for the QS-CDMA system

This paper proposes a novel introduction of the multidimensional multilevel block coded modulation (ML-BCM) to the quasi-synchronous CDMA (QS-CDMA) system, where the code delay uncertainty at the base station is limited to a small number of chips. To improve the performance of the QS-CDMA system, we employ the Leech-lattice based 24-dimensional BCM in the overall BCM-QS-CDMA modulation. The resulting transmitted constellation is more robust to fading. Computer simulation results show a significant coding gain compared to the uncoded and convolutional code based QS-CDMA systems.