Simulation And Analysis Of The Performance Of 256 OFDM In 802.16a

OFDM has been applied in communications for nearly 40 years. At the beginning, it is mainly used in military field and until recent years it gradually comes into commercial field and becomes focus of the telecommunication industry.IEEE 802.16 series is a global new star in wireless communication field. The World Interoperability for Microwave Access (WiMAX) is an industry-led corporation formed to help promote the IEEE 802.16* standards. The membership of WiMAX includes the whole industry chain from carriers, manufacturer and components providers.OFDM is a key technical in IEEE 802.16a standard. The IEEE 802.16a standard defines 3 modulation styles: Single Carrier, namely 'WirelessMAN-Sca'; OFDM 256 Sub-carriers, namely 'WirelessMAN-OFDM'; OFDMA 2048 Sub-carriers, namely 'WirelessMAN-OFDMA'. Aside, there is OFDM modulation style aims at 2 ~ 11GHz uncertified band, called 'Wireless HUMAN'.This article describes the development and simulation of 256 sub-carriers OFDM applied in IEEE 802.16a wireless environment.Firstly, the author makes an overview of 802.16a fixed wireless access system and OFDM technique, pointing out the importance of OFDM in WiMAX. Then the OFDM communicating model is set up and described, including every component and their principles in this model. Besides OFDM, the key techniques in this system includes DQPSK, convolutional encoding interleaving and (I)FFT .Wireless environment for Wireless MAN is also investigated and the channel model is set up for 802.16a.