Multi-carrier parallel combinatory DS/CDMA system: bandwidth efficient multiple access scheme for indoor wireless communication

As a data transmission rate must be increased as required to support in the future high-speed wireless communication systems, the conventional DS/CDMA scheme suffers considerably from an intensive processing requirement for the increasing spreading rate to combat the inter-chip interference due to multipath fading inherent in the wireless channel. A parallel combinatory (PC) CDMA/OFDM scheme is considered as one possible variant access scheme to realize a bandwidth efficient transmission at high data rate while maintaining the high-capacity feature of the DS/CDMA scheme. This scheme combines the parallel combinatory feature of the existing PC/CDMA to achieve the high bandwidth efficiency and the orthogonal carrier multiplexing feature of OFDM to reduce the multiple user interference among sub-carriers. Our analysis of the bit error rate for the asynchronous CDMA system investigates the performance characteristics of the proposed system and shows the performance comparison with other types of multi-carrier DS/CDMA systems