Teletraffic performance of microcellular personal communication networks

Abstract

Teletraffic performance of a personal communication network (PCN) based on city street microcells catering for pedestrian mobile users is analysed. By opting for microcells, the network capacity dramatically increases as well as the spectrum efficiency, but the network must be able to accommodate substantial increases in the number and rate of call handovers. A teletraffic analysis is performed to determine the new and handover call rates as well as the channel holding time of the PCN. Next, a teletraffic model is established to determine the teletraffic performance parameters, such as the blocking probabilities of new and handover calls, the overall grade of service, the carried traffic, the channel utilisation, and the spectrum efficiency. Techniques to reduce the premature termination of calls in progress are proposed and modelled. These include reserving a set of channels exclusively for handovers at each microcell fixed station, and deploying a macrocell to overlay a microcellular cluster, where the macrocell base station is assigned channels for handover requests from mobiles who cannot be serviced by their microcell fixed stations. A large spectral efficiency of 1000 Erlang/MHz/km2 is achieved at nominal blocking probability of 2%, while the probability of premature termination is reduced to less than 10−4 in the presence of high call rates in excess of 0.06 calls/s/microcell. The results presented will assist network planners in predicting teletraffic performance.