A Non-homogeneous QBD Approach for the Admission and GoS Control in a Multiservice WCDMA System

We consider a WCDMA system with real time (RT) calls that have dedicated resources, and data non-real-time (NRT) calls that share system capacity. We apply reservation of some resources for the NRT traffic and assume that this traffic is further assigned the resources unused by RT calls. The grade of service (GoS) of RT traffic is also controlled in order to allow for handling more RT calls during congestion periods, at the cost of degraded transmission rates. We consider both the uplink and downlink, and derive performance evaluation results regarding user-perceived QoS parameters, namely the blocking rates of RT calls and sojourn time of NRT calls. On what concerns the bandwidth-sharing policy of NRT traffic, we compare WCDMA behavior in the presence of a high data rate scheme. Finally, we extend our results to cover NRT admission control schemes and examine blocking behavior and transfer times of NRT traffic.