Meeting QOS requirements in a cellular network with reuse partitioning

Reuse partitioning is a technique for providing more efficient spectrum reuse in cellular radio systems. A cell in such a system is divided into concentric zones, each associated with an overlaid cell plan. Calls that arise in the periphery of the cell have fewer channels in their availability than those arising close to the base station and therefore they experience higher blocking rates. In this paper we consider the problem of balancing uniformly the blocking probability throughout the cell offering a fair treatment to the whole area within the cell, by controlling the allocation to the different channel layers. A policy that minimizes the maximum blocking probability experienced at any location of the cell is identified and is shown to be of threshold type. The policy satisfies any achievable constraint on the blocking rate uniformly throughout the cell. An adaptive scheme that adjusts the threshold based on estimates of the blocking probabilities in the different zones of the cell is proposed. This scheme tracks the optimal threshold effectively without any knowledge of the traffic parameters. Simulation study shows that substantial capacity improvements are achieved by the application of the optimal channel assignment policy, over the uncontrolled system