Performance Evaluation of IEEE 802.11 DCF in Single Hop Ad Hoc Networks

Abstract

The mathematical modeling of IEEE 802.11 CSMA/CA has received considerable attention in the past few years. However there is lack of significant work considering the presence of buffer in wireless networks. Also most of the work has not followed IEEE specifications regarding inclusion of retry limits. This paper presents a new analytical model for performance evaluation of IEEE 802.11 single hop networks. The work presented here takes into consideration the presence of first order memory buffer along with the effect of traffic arrival which obeys Poisson distribution. In addition, we have considered the short retry limit to accommodate IEEE 802.11 specifications. On one hand, lack of buffering leads to high delays and under utilization of the channel. Also the absence of short retry limit tends to overestimate the throughput. By accommodating both the shortcomings, it has been proved that our model predicts the behaviour more accurately. We have been carrying out extensive simulations to validate results of our model. We have presented the performance evaluation of both the access mechanisms present in 802.11 MAC protocol.