Study On Transmission Performance Of Orthogonal Frequency Division Multiplexing In Wireless Access Network

The development of wireless communication technology brings great facility to people's life. Wireless multimedia communication is the future of wireless communications, and high data rate is the basement of wireless multimedia communication. Orthogonal Frequency Division Multiplexing (OFDM) has better bandwidth efficiency and increased robustness to multipath fading and to interference than single carrier adaptive equalization modulation techniques in wireless environment, OFDM has became the core technology of kinds of high speed wireless access due to its better characteristic.The properties of wireless access channel has great influence on OFDM systems performance, so it is the fundament knowledge of OFDM systems in application; on the other hand, OFDM use IFFT to produce orthogonal sub-carriers, high rate signal processing technology is very important. OFMD also have it disadvantages, for example, the big signal Peak-to-Average Power Ratio result in OFDM is very sensitive to system's non-linearity; symbol synchronization error will destroy orthogonal between sub-carriers.This paper start from OFDM system work principle, describe the FFT realize method and Physical action of Cyclic Prefix of OFDM. Then simulating the OFDM basic property with simulate software and analysis the result. The emphasis of this paper is to analyze the principle of use Cycle Prefix to realize symbol synchronization, and point out it disadvantage in multipath propagation, we proposed a new schematic. The major drawback of OFDM is the large Peak-to-Average Power Ratio (PAR) of the transmit signal, Existing solutions do not attack this PAR issue in a systematic way however. We discuss and compare a broad range of such techniques and organize, andpoint out its advantages and disadvantages.