Performance Enhancement of WLAN Using 802.11n and MIMO Technology

Abstract

802.11n is IEEE wireless standards that significantly improve throughput and range of Wireless Local Area Networks(WLAN) compared with other 802.11 stan dards. It is expected to provide a throughput of over 100 Mbps, which is twice that of 802.11g. This difference is because it is designed to operate in both 5 GHz and 2.4 GHz frequency band. The key issue in wireless communication is multi-path propagation. This multi-path propagation occurs when signal bounces buildings, walls and other obstacles and arrives at the receiver at different times and from different paths. If the time difference is large enough, the receiver gets confused and can’t interpret the signal causing retransmissions and therefore reducing the speed and data rate of the 802.11 networks. IEEE802.11n takes the advantages of multi-path propagation to increase throughput to speeds above 100 Mbps, by using MIMO or in other words multiple transmitters and multiple receive (MIMO) antennas. It uses spatial diversity to induce multi-path for the purpose of recombining the multiple signals to increase the signal gain, and channel multiplexing to send multiple signals using multiple antennas, therefore multiplying speeds, increases the range and enhances the performance.