OFDM Modulation Technique And The Implementation And Realization In Wlan

Wireless Local Area Networks (WLAN) is combination of wireless communication technology and internet. WLAN experience a growing popularity recently. Orthogonal frequency division multiplexing (OFDM) is a kind of multicarrier digital modulation. It modulates high speed serial datas to many parallel subcarriers, so besides high bandwidth efficiency, there are many other advantages in OFDM, such as the high robustness to frequency-selective fading and the reduction of intersymbol interference (ISI). The realization of hardware is convenient by IFFT/FFT modulator and demodulator. Maybe the most prominent system employing the OFDM modulation technique is the WLAN standard IEEE802.11a.First, we analyze the basic theory and key technique of OFDM modulation system. Then, we make some research for OFDM techniques under IEEE802.11a standard in WLAN system. We present the design and implementation of a simulation model for physical layer in the IEEE802.11a WLAN system with the simulation tool Matlab.And based on these analysis and research, using Quartus II software and VHDL language, we complete the designment, realization and simulation of OFDM modulation system under IEEE802.11a standard. Through the simulation, it proves that the designment of the OFDM modulation system is feasible and effective.