RATE ADAPTATION TECHNIQUES IN WIRELESS NETWORKS (WLAN)

The throughput of Rate adaptation in wireless networks 802.11is inclined by many parameters. Few of them are channel conditions, SNR, signal fading due to distance, Frame collisions from simultaneous transmissions and Interference from other sources etc. Among these, channel condition is most significant from the rate adaptation point of view. There are many standards for the data transmission provided by IEEE. IEEE 802.11 wireless networks (WLAN) supports multiple data transmission rates. There are many techniques and many definition of rate adaptation. The simplest way to describe the rate adaptation - : “Rate adaptation is the determination of the optimal data transmission rate most appropriate for current wireless channel conditions”. The Rate Adaptation algorithms used in the wireless network adapters are responsible for selecting the bit-rate used by the hardware when transmitting frames over the wireless channel. This algorithm heavily affects the performance of wireless devices. Rate adaptation is the process through which data may be send from the host node to the destination node with the maximum throughput in which nodes adap the data rate dynamically according to varying channel conditions