In the recent years, WLAN (Wireless Local Area Network) standards have been evolving rapidly. The IEEE 802.11g standard was set in 2003 as a new wireless protocol aimed at enhancing existing data rates. This paper focuses on the performance of IEEE 802.11g system based on OFDM (Orthogonal Frequency Division Multiplexing) using modeled transmitter and receiver. We investigate the performance analysis through computer simulations over the JTC (Joint Technical Committee) realistic channel model for various modulations like BPSK, QJPSK, 16-QAM and 64-QAM. © 2005 IEEE.