The Research Of The OFDM Optical Fiber Transmission System Performance

Orthogonal frequency division multiplexing (OFDM) technology has thecharacters of narrow-band interference and multi-path fading resistance, thedispersion effect in the optical fiber communication channel with the wirelesscommunication channel is similar to the multi-path effect, through the orthogonalfrequency division multiplexing (OFDM) technique and the combination of opticalfiber communication system, to realize high speed and high quality informationtransmission caused extensive research both at home and abroad.The development of the fourth generation mobile communication system and itsprospects and the core technology of4G mobile communication system are introducedin this paper。The data model of OFDM principle and modulation and demodulationhas been studied in the OFDM system. For the key problems in OFDM technology:add protection interval，to join the cyclic prefix, with forward error correction codingand so on are expounded. This paper is based on the theory of OFDM optical fibertransmission system in the aspects of the research.1. The effectiveness of modulating OFDM signal to optical fiber transmission onoptical carrier has always been the researching hot-spot. The simple structure andhigher working frequency of external modulation mode is favored by us. Through thestudy of the external modulation mode of double sideband modulation (DSB), singlesideband (SSB) modulation and suppressed carrier modulation (OCS) theory, wecompare the dispersion factor’s influence on the three kinds of modulation mode. Asimulation is established to realize the wired and wireless transmission of the opticalwireless communication transmission system.2. Set up a single sideband light load based on phase modulation OFDM-ROF(Radio-over–fiber) transmission system, ROF system transmission performance isstudied by a simulation model of theoretical and simulation analysis using directdetection technology of OFDM. The transmission performance of the system isaffected by the dispersion constant, symbol rate, modulation mode, light power sizeand so on. Through channel equalization algorithm and using fiber module implementthe system of dispersion compensation.3. Set up a kind LPDC-OFDM transmission system simulation model based onsingle side band. Experiment established a60GHz millimeter wave load based onLDPC-OFDM transmission system. The using of LDPC error correction coding iscompensated for the effects of dispersion in optical fiber signal, improving the qualityof the signal transmission.