In the past decade there has been a steady growth in development and implementation of wireless Local Area Networks and emerged as in the largest sectors of the telecommunication industry. Wireless local area network (WLANs) is a new medium of access technology in the Local Area Network (LAN) world. Mostly WLAN applications are used in public sectors such as airports, banks, hotels, offices, city centers because of the flexibility of the people. Orthogonal Frequency Division Multiplexing OFDM has been adopted as a transmission technique for high data rate in WLANs. Matlab Simulation model based on IEEE 802.11a using different Modulation and Demodulation techniques such as BPSK, QPSK and QAM to analysis the best performance of IEEE WLAN physical layer with implementation of OFDM under different error correcting and detection technique.