The Impact of Hidden Nodes on MAC Layer Performance of Multi-Hop Wireless Networks Using IEEE802.11e Protocol

The IEEE802.11e network provides different with QoS (quality of service) guarantee for different traffic streams. The Enhanced Distributed Channel Access(EDCA) in IEEE802.11e MAC protocol is proposed to support prioritized QoS on the basis of the Distributed Coordination Function(DCF) in IEEE802.11. This is first paper which assesses the effectiveness of the IEEE802.11e access mechanism in multi-hop wireless networks by quantitative analysis and simulation. We build a new modeling analysis methodology for the 802.11e access mechanism in multi-hop environments with hidden nodes problem. By using M/G/1/K queuing model, we can analyze a few MAC layer performance metrics of multi- hop wireless networks, such as MAC layer throughput, the mean packet delay and packet discard probability, and give better explanation to performance degradation in delay and throughput due to the impact of hidden nodes. The proposed model is calculated numerically and validated against simulation results, we observed a good match between the analytical model and simulation. Because the performance of 802.11e supporting class- based differentiated QoS degrades considerably in multi- hop environments, it is necessary to investigate the scheme which can resolve hidden nodes problem.