A non-homogeneous QBD approach for the admission and GoS control in a multiservice WCDMA system
We consider a WCDMA system with two types of calls: real time (RT) calls that have dedicated resources, and data non-real-time (NRT) calls that share system capacity. We consider reservation of some resources for the NRT traffic and assume that this traffic is further assigned the resources left over from the RT traffic. 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 downlink (with and without macrodiversity) as well as the uplink, and derive performance evaluation results regarding transmission rates, blocking of RT calls and sojourn time of NRT calls, under different traffic characteristics. On what concerns the bandwidth-sharing policy of NRT traffic, we compare WCDMA behavior in the presence of high data rate schemes. Finally, we extend our results to cover NRT admission control schemes and examine blocking behavior and sojourn time of NRT traffic.