Power assignment strategies and traffic control for wireless multimedia DS-CDMA systems

We propose a wireless multimedia DS-CDMA system with dynamic power assignment (DPA) for adaptive traffic control. The system supports service groups with different quality of service (QoS) requirements specified in terms of both transmission bit rate and bit error rate (BER). The optimal received power level for each service group is obtained by minimizing a cost function consisting of the weighted sum of the blocking rates of different service groups subject to their QoS requirements. The performance is compared to a similar system with fixed power assignment (FPA) in which the received power level for each service group is assigned based only on its transmission bit rate. Simulation results show that DPA algorithm can support much higher offered traffic loads, on merit of the blocking probability. By implementing the cost function with different weighting coefficients, we can assign different blocking probabilities to different service groups to cope with the demands in the system. The DPA algorithm therefore plays the role of a "movable blocking boundary" in the system which can accommodate multimedia traffic and priority-based capacity access.