Capacity of a Packet Switched Cellular Network with Link Adaptation

The purpose of this paper is the calculation of the teletraffic capacity of a cellular radio network that uses packet switching for voice transmission. In addition, the network can support two types of voice connections: Full Rate and Half Rate, depending on the channel conditions. Switching between the two types is achieved by using link adaptation. We formulate a two-dimensional birth-death model in order to describe the channel occupancy distribution and calculate the average radio utilization. We consider five different frequency reuse patterns and in each case, we calculate the maximum traffic load per cell that the network can serve, provided that the call blocking probability is less than 2%, the average packet dropping probability is less than 1% and an adequate carrier-to-interference ratio is maintained at the cell border. We finally compare the capacity results obtained with the capacity of a packet switched system without link adaptation and a circuit switched system with and without link adaptation, under the same operating requirements.