Access Delay Analysis of IEEE 802.11 DCF in the Presence of Hidden Stations

In this paper, we present an analytical model to evaluate the hidden station effect on the access delay of the IEEE 802.11 distributed coordination function (DCF) in both non-saturation and saturation condition. DCF is a random channel-access scheme based on carrier sense multiple access with collision avoidance (CSMA/CA) method and the exponential backoff procedure to reduce packet collisions. However, hidden stations still cause many collisions under CSMA/CA method because stations cannot sense each other's transmission and often send packets concurrently, resulting in significant performance degradation. Prior research has built accurate access delay model for 802.11 DCF. However, the hidden station effect on the performance has not been adequately studied. Our model generalizes the existing work on access delay modeling of 802.11 DCF for both non-saturation and saturation conditions, under the hidden-station effect. The performance of our model is evaluated by comparison with ns-2 simulations and they are found to agree.