Research On Link Adaptive Technology Of IEEE802.11n Protocol

Take advantage of its mobility and convenience Wi-Fi is being more and more widelyused in the home,office areas and public places. The Internet is no longer bound by the wiredmedium and gradually steps into the mobile era. Along with the continuous development of avariety of wireless products, users’ requirements of speed, throughput and reliability of thenetwork are also increasing. Traditional wireless LAN technology has become increasinglyunable to meet the user’s requirements.IEEE802.11n is the standard of next generationwireless LAN.Compared with the previous IEEE802.11standard, its main feature ishigh-throughput.To this end,the standard is not only using40MHz channels,MIMO, OFDMand other advanced technology in the physical layer,doubling the transmission rate,but alsojoining frame aggregation mechanism, block Ack mechanism and link adaptation technologyin the MAC layer,making data frame structure optimized and the performance of MAC layerenhanced.So the network throughput can be improved.This paper is focus on the link adaptation technology of802.11n network.A rateadaptation algorithm and an adaptive aggregation algorithm are proposed for802.11n network.Both algorithms are based on the same principle, the direct measurement of channelinformation.Before transmitting of data frame,it will get the channel information first.Thenmake the decision of data rate and frame length according to the channel condition.Byselecting the best transmission scheme which is most adapted to the channel,we can achievetotal throughput improvement of the network.Meanwile,we set up a802.11n WLAN simulation platform to verify the proposed linkadaptation algorithms based on OPNET network simulation software. In the end, we analyzethe simulation results and compare with the traditional algorithms, to verify the superiority ofthe proposed algorithms.That indicates the algorithms can effectively improve networkperformance.