The impact of long-range dependent traffic in a CDMA system supporting real-time services

This paper examines the impact of long-range dependent real-time variable bit rate (rt-VBR) traffic in a multi-service CDMA system that has been dimensioned using a short-range dependent traffic model. A simulation of the system is performed using both a self-similar Pareto renewal process and a Poisson process as traffic models. The importance of traffic model choice when dimensioning the system is established by comparing the QoS delivered under each traffic model. Simulation results show that the factor of performance difference between the two models is heavily dependent upon the level of self-similarity in the traffic, traffic load and propagation conditions. This difference is most significant when: the Hurst parameter exceeds approximately 0.75; there is a medium traffic load; and the probability of propagation loss is low. The scheduling policy is shown to skew the relative importance of the traffic model to each service.