TELETRAFFIC MODELS FOR URBAN AND SUBURBAN MICROCELLS - CELL SIZES AND HANDOFF RATES

As cellular systems evolve into personal communication networks, teletraffic modeling of users will become crucial. Teletraffic models are required for cellular system layout and planning and to evaluate tradeoffs in system design issues. In this paper, we begin with a study of handoff rates in evolving cellular systems. Using simple geometry, we show that in macrocells with homogeneous traffic the handoff rate per call increases only as the square-root of the increase in the call density. The situation is different in microcells where individual traffic paths become important and the homogeneous traffic model does not apply. Under smooth flow, the handoff rate along a traffic path goes up linearly with the number of new boundaries intersecting the path. Hence, in urban and highway microcells the handoff rate per call increases linearly with increasing call density. We propose a parametric model based on results from vehicular traffic theory, that applies to vehicles and pedestrians in urban, suburban, and highway cellular systems. The model helps quantify various design tradeoffs. With reasonable parameter values, we find that microcells are unnecessary in urban environments if the pedestrian penetration is small and that an architecture with microcells and overlaid macrocells is required only if a majority of teletraffic is pedestrian generated.