Communication capacity of sectored CDMA systems

This paper shows that the communication capacity of CDMA systems can be enlarged further, by adopting array antennas, which involves a joint multiuser detection approach that is based on CDMA codes and their spatial information. In contrast to SDMA-CDMA systems the CDMA systems with array antennas in this paper do not have spatial coding, since it causes the frequent spatial handoff problem. Thus the new CDMA systems can be of much higher communication capacity than the CDMA systems which are not sectored. Analyzing the array pattern of array antennas, we show that the interference of other sectors, also multiple access interference (MAI), can be effectively suppressed by the array antennas for a CDMA system to be sectored by array antennas. The design and analysis of WLS multiuser detector in the new CDMA systems is presented to detect CDMA signals with different spatial information. Simulations show that a sectored CDMA system can be of better SINR (signal to inference plus noise ratio) and BER (bit error rate) performance even it has three times the users compared. to the number of cells of present CDMA systems.