| The impact of customer behavior plays an important role in the planning of multi-media cellular mobile communication networks. In fact, the quality of service (QoS), such as waiting time and accessibility, that is experienced by each individual customer is the main factor in the evaluation of system performance. In this thesis, we are going to investigate the waiting time/delay of a broad class of mobile communication system-oriented queueing models. Both exact analytic and approximation algorithm techniques are employed in order to obtain the exact and approximate waiting/delay distribution of those models. We concentrate on probability distribution instead of mean value because an one-point estimate is not sufficient to provide a good performance evaluation. We propose different queueing models in order to describe different characteristics of mobile systems. In general, mobile customers can be divided into two main categories, fresh customer arrivals and handover customers. A fresh customer arrival is a customer who initiates a new call and a handover customer is a customer who moves from an adjacent cell. Each category can be further divided into voice and data and each sub-category can be classified according to its moving speed. Because the handover customers have a significant impact on the quality of service, a set of channels is reserved for them at each base station and they are called guard channels. Also, different server control mechanisms are implemented in order to optimize channel (or server) utilization. |
