Performance of multirate CDMA transmission in cellular environment

This paper investigates a CDMA cellular system that provides multirate services to slow and fast moving mobile terminals. The system operates in a cellular overlaid configuration where each user transmits in bandwidth proportional to the chosen service rate. The performance of the system is simulated in the presence of multiuser interference accruing from several users transmitting at independently chosen rates. A total of six cases with different combination of data rates are investigated. It is shown that the system can sustain a maximum number of users slightly higher than half the processing gain; in some cases this number is higher. The results show that the performance is not affected when the average powers of the interfering users vary within -5 and +5 dB of the desired user power. The variable bandwidth system is shown to outperform the fixed bandwidth system