Abstract: “Wireless local area networks(W-LANs) have become increasingly popular due to the recent availability of affordable devices that are capable of communicating at high data rates.The IEEE 802.11a standard is WLAN standard which uses orthogonal frequency division multiplexing technology.The standard provides data rates upto 54 Mbps making it a good candidate for high-speed wireless communication. It utilizes different modulation schemes for different data rates,since the choice of modulation scheme to be used depends upon the current state of the transmission channel,Recent wireless devices often support multiple modulation schemes, and hence multiple data rates are possible.The selection of the best rate is obtained through a rate adaptive MAC protocol called the Receiver-Based Auto Rate (RBAR) protocol[1].The performance of the standard is studied under the indoor wireless environment for Multipath Rayleigh channel.In this paper ,the simulation results for modulation schemes 16-QAM and 6”

Keywords: OFDM, WLAN, BER,SNR, RBAR.