Overload performance and user mobility for a mobile communication system

An important parameter in the analysis of a communication system is the channel holding time of a call. In a mobile communication system, the cell channel holding time may be different than the call duration due to the mobility of the user. To study this impact of the user mobility, a new and general mobility model is presented and analyzed. This model is valid for a wide variety of different types of user mobility and is used to derive the Laplace transform of the probability density function for the channel holding time. The channel holding time is expressed in terms of the mobility model parameters and the call duration. From this important result, the average and coefficient of variation of the channel holding time are presented and discussed. The impact of the user's mobility upon each is examined. A comparison between this model and one which assumes constant user speed is also presented.;The overload analysis of a mobile communication system which queues both handover requests and new call arrivals is presented. The system is analyzed for overload due to either new call arrivals, handover requests, or both. This system can be modeled as a quasi-birth death process (in certain regions of operation) and a numerical method based on a matrix geometric approach is used to determine the solution. The throughput, average waiting time, and carried load of new call arrivals and handover requests are determined as a function of the overload control design parameter. The performance of this system in both the traditional macrocell and emerging Personal Communication Services environments is examined and discussed. An illustrative example applying the results of the mobility model analysis to the overload performance and design is also presented.