A SIMPLE CONGESTION-RESILIENT LINK ADAPTATION ALGORITHM FOR IEEE 802.11 WLANS

摘要

A COLA algorithm for IEEE 802.11 WLANs(Wireless Local Area Networks) is provided to acquire the optimal packet processing amount beyond the wide range of SNR(Signal to Noise Ratio) values and be applied to a 802.11 network quickly and directly without an additional overhead. A COLA(COngestion-resilient Link Adaptation) algorithm measures the average number of a channel-induced error by a transmission error number and the total number of transmission attempts in a given current mode if collision probability and channel error probability have no common element. If the average number of the channel induction error is greater than or the same value as a mode drop boundary in the current mode, the mode drop boundary is a preset boundary. When the mode drop boundary is one, all other link adaptation algorithms called as COLA are performed. The COLA algorithm performs each transmission attempt. The COLA is tested in 802.11a BSS having n-wireless stations to which a link adaptation algorithm is mounted. If a mode against channel quality due to the incorrectness of a mode decreased during collision, the main cause of a transmission error, is plotted, the n-wireless stations measure the COLA and prevent the collision. A mode function remains whenever n changes during the prevention of the collision.