Fuzzy-based cross-layer transmission scheme with QoS considerations for wireless mesh networks

IEEE 802.11 wireless networks utilize a hard handoff scheme when a mobile station is travelling from one area of coverage to another within a transmission duration. When the station is running a real-time multimedia application receiving data from the wireless network, in each pair of neighboring MAPs, contention scheme is used to transmit data. The latency for successfully transmitting data is seriously lengthened so that the deadlines of data frames are missed with high probabilities. In this paper, we propose a fuzzy-based cross-layer transmission (FCLT) scheme with QoS considerations for IEEE 802.11 mesh wireless networks, which utilizes the grey model and the fuzzy theorem. In the handoff procedure, some ratio of real-time data frames will be relayed to the next MAP based on received signal strength indication of PHY layer and contention window of MAC layer, which can meet the minimal QoS requirements. By utilizing FCLT, the ratios of data frames missing deadlines will be significantly improved to meet timing requirements for real-time multimedia applications. We develop a simulation model to investigate the performance of FCLT. The capability of the proposed scheme is evaluated by a series of experiments, for which we have encouraging results.