Priority mechanism for QoS control in CDMA system through dynamic power control

Future wireless systems will have to support multimedia services such as voice, data and video. Issues in providing multimedia services on wireless systems include multiple access, bandwidth rationing, scheduling and power control. In this thesis, we address the last issue. CDMA is assumed to be the access method. Each of these services has different Quality of Service (QoS) requirements, maximum power and packet time-out constraints; in order to achieve the required QoS, they can alter their transmission. In this work, we present a novel Power Control With Priority Scheduling (PCWPS) algorithm for a wireless CDMA system, which achieves reliability and efficiently control packet loss due to timeout violation for simultaneously transmitted multimedia traffic, as well as minimizing system total interference. Our power control algorithm requires information about each traffic class instant state, as well as the wireless channel condition at the beginning power update iteration. Based on this information, the optimum allocated power can be calculated through linear or nonlinear programming methods. The simulation results show that our algorithm achieves good performance in term of packet loss due to timeout