Improvement of QoS in Wireless N/W Using Call Admission Control Scheme

A call admission control (CAC) algorithm used for WCDMA prioritized uplink for UMTS, which combines QoS tolerance and service differentiation by priority for voice, data, multimedia. This CAC algorithm gives preferential treatment to high priority calls, such as soft handoff calls, by reserving some bandwidth margin (soft guard channel), Power consumption, no. of users (load) to reduce handoff failures. In addition, queuing is also used to enhance the service quality. The algorithm uses the effective load as an admission criterion and applies different thresholds for new calls, handoff calls, bandwidth requirement, and power consumption. Finally, the study considers three types of services: voice, data and multimedia calls. Use of CAC algorithm indicates that this algorithm reduces the drop of handoff calls and increases the total system capacity and performance; hence the Grade of Service (GoS) of the system can significantly be improved especially in case of high mobility environments.