A tool to calculate Erlang capacity of a BTS supporting 3G UMTS system

The second-generation (2G) wireless systems are primarily designed for voice services. The cell capacity is obtained by simulation for the given mobile environment. The cell capacity is used in network planning. The proposed 3G wireless systems mainly address data services. A 3G system allows users to use multimedia services. Therefore, there can be several different combinations of the voice and data services that may occur at a base station transceiver (BTS). This will require major time-consuming simulations to obtain the Erlang capacity of the BTS for all possible combinations of the services and will complicate the network planning process. The objective of this paper is to present a simple tool that analytically models a BTS. We do not have to depend on major simulations to obtain the BTS capacity for the given set of services. We develop the Erlang capacities of a BTS for voice services, real-time (circuit-switched) and non-real-time (packet-switched) data services. We use the capacity figures of the uplink and downlink with the link budget to calculate the maximum cell radius for each service type in an urban environment. We show the effect of uplink and downlink information bit rate on the cell radius.