The Wireless Engset Multi-Rate Loss Model for the Handoff traffic analysis in W-CDMA networks

The call-level performance modelling and evaluation of 3G cellular networks is important for the proper network dimensioning and efficient use of the network resources, such as bandwidth and power. In the case of the wideband code division multiple access (W-CDMA) cellular networks, this task is complicated, not only because of the so called soft blocking, the multiple access interference (MAI) and the heterogeneous traffic, but also due to the handoff process. In this paper, we propose a new teletraffic model for the call-level analysis of handoff traffic in the uplink of W-CDMA networks where multiple services with finite number of traffic sources are accommodated. Parameters related to the soft blocking and MAI are included into the model. The proposed model is described by a discrete time Markov chain. An efficient recurrent formula for the calculation of the system state probabilities is derived. Based on this formula, blocking probabilities of both new and handoff calls are determined. The accuracy of the proposed model is evaluated through simulation and is found to be very satisfactory. Moreover, we show the necessity of distinguishing the handoff traffic from the new traffic, in respect of blocking probabilities.