Analysis of traffic distribution in cellular networks

Accurate air interface traffic forecasting and dimensioning is of importance in any cellular network for achieving cost and quality requirements. Tunnicliffe et al. (1998) analysed the appropriateness of the Erlang B model to estimate the mean call blocking experienced by cellular traffic using the traditional confidence interval method. This paper presents a modified confidence interval method to compare the mean blocking of the measured data and Erlang B results. In addition to a more complete study of the mean, the blocking distribution is also considered. The Erlang loss model (ELM) is studied to completely characterise the distribution of blocking using the ELM. Exact expressions for the busy time distribution are derived for this study. The results presented in this paper indicate that Erlang B formula is an appropriate model for calculating mean call blocking on the air interface. The ELM on the other hand appears to be rather a poor model for the overall blocking distribution. Further study is needed to establish the appropriateness of Erlang B formula as a general tool