A novel collision probability based adaptive contention windows adjustment for QoS fairness on ad hoc wireless networks

It is crucial to achieve Quality of Service (QoS) on IEEE802.11 in order to provide stable and reliable communication for real time and multimedia applications. Most of the recent QoS techniques for Ad Hoc Networks rely on basic QoS classifications such as Enhanced Distributed Channel Access (EDCA) and Hybrid Coordination Function Channel Access (HCCA) with stationary backoff range for specific services, without considering overall resource consumption and the external correlation among terminals. In this paper, a novel contention window adjustment QoS scheme, as a special case of QoS classification, is proposed for achieving QoS-fairness on Ad Hoc Networks. It applies dynamic automatic QoS assignment with low complexity by considering the restriction among various terminal requirements. Throughput estimation with a proportional relation between throughput and backoff parameters is discussed based on a Markov chain model of a saturated Ad Hoc Networks. We measure the performance of different QoS algorithms theoretically and verify improvements of our algorithm on QoS-fairness with detailed simulations.