UMTS Uplink Loading Probability Calculation Using Log-Normal Interferers Contributions

In this paper we introduce the probabilistic notion of uplink loading in a UMTS network subject to uplink interferers from both the home cell and other neighbouring cells. Our study is based on the assumption that, for a given UMTS cell, all the interferers in the uplink are log-normally distributed and that the Gaussian noise is also taken into account. The latter is considered as a constant contribution to be added to the sum of all interferers that are summed up using Wilkinson’s [1] calculation method. The uplink loading h is regarded as a random variable as it is directly dependent upon uplink log-normal interferers. In this paper we propose a new way of assessing this uplink loading and for a given User Equipments spatial distribution snapshot. Subsequently the probability that the uplink loading exceeds a given threshold, say h0, is thus derived and for different correlation figures and different noise levels as well.