A dynamic rate adaptation with fragmentation MAC protocol against channel variation for wireless LANs

The paper proposes a fragment and rate matching (FaRM) MAC protocol for wireless local area networks (LANs) to resist the frequent changing of channel quality and increase the network throughput. In wireless environments, channel quality varies with time. FaRM dynamically detects the current SNR to estimate the channel quality through the control frame exchanges. A Finite State Markov Chain (FSMC) is adopted to predict the variation of the channel condition. According to the results generated from FSMC, FaRM enables a station to select an appropriate transmission rate as well as an acceptable fragment length dynamically to transmit in order to both increase the reliability and shorten the channel access time of the transmission. The simulation results show FaRM has better performance, higher transmission reliability, and lower transmission delay time by fragment and rate matching.