Evaluation of inter-system handover frequency in a hierarchical structure

Mobile terminals that have the possibility to make intersystem handovers will increase in numbers and importance as the interaction between wireless networks evolve. New services and applications are pushing this system development. Users want their mobile terminal to be able to make seamless handovers both within the present wireless network as well as to other wireless systems. In this paper such a mobile terminal is foreseen and its system utilization applied in a three level hierarchical structure of wireless systems is presented and analyzed. The intersystem handovers between the three different levels (systems) are investigated for different settings of for example overlap and load. The implementation of new services in the systems effect on the performance is analyzed while altering the proposed scenarios. The handover rates and blocking probabilities are discussed and thoroughly explained. Further, the mean number of handovers per connection is investigated.