Study on wideband CDMA modulation, power control and wireless access for CDMA multimedia systems

In this paper, we present our researches on wideband code division multiple access (W-CDMA) multimedia wireless system which is sponsored by Communication Subjects of High Technology R&D Programme of China. We propose a W-CDMA modulation scheme of variable transmission rate, partial-balance power control algorithm, and wireless access method for variable access rate. The proposed algorithm integrates traffic priority ranking and transmit power control and access information rate control. Our simulation results show that the partial-balance power control algorithm can render the special QoS requirements of traffic with higher priority orders guaranteed and maximize the CIR of the traffic with lower priority orders. Access rate adaption provides higher channel usage and more successful access probability than the fixed access rate algorithm. Based on the above techniques, we also develop a experimental system which consists of base station and multimedia terminals.