MODELING OF IEEE 802.11 COMPUTER NETWORKS OPERATION AT INCREASED INTERFERENCE INTENSITY

Abstract

Context. High level of industrial noise increases the loss of information frames during transmission, which in turn decreases the network throughput. We propose a mathematical model of IEEE 802.11 networks operation under conditions of increased interference intensity. Objective. The purpose of this paper is to express in an explicit analytical form the effect of bit error rate (BER) on the probability of frame transmission and the network throughput. Method. We have proposed the method for constructing a model that allows you to directly calculate the dependence of the frame transmission probability on the number of stations operating in saturation mode, which is convenient for engineering calculations. The values of the model coefficients were selected by comparing the calculation results with the results obtained using the known Bianchi model, which describes the network operation in the form of a Markov process. In the range of up to 23 stations working with one access point, which corresponds to a collision probability of up to 0.5, the indicated dependences for both models satisfy each other with an accuracy sufficient for the practical application. An expression for the network throughput has been defined. Results. The results of the model development were used to take into account the effect of interference intensity on the information transfer process. This made it possible to explicitly express the effect of BER on the probability of frame transmission and the network throughput in the case of variations in the length of the frames and with a different number of competing stations. The degree of throughput reduction has been determined for BER = 10–5, 5∙10–5, 10–4 and increasing value of minimum contention window. Conclusions. In this work, a mathematical model has been developed for direct calculation of the probability of frame transmission and network throughput at different levels of BER.