The Study Of Co-ofdm Single-mode Fiber Communication Ssytem Simulation And Timing Synchronization Algorithm

Coherent optical orthogonal frequency division multiplexing (CO-OFDM) is a new type of optical multiplexing technology. The technology has the merits of coherent detection and OFDM, so it can realize the high-speed optical fiber transmission without dispersion compensation, while the requirement of optical amplifiers has been reduced. And thus its transmission capacity can be enhanced, but also has a good upgrade in the existing network infrastructure, as well as the expansion is convenient. Therefore, it has broad application prospects in the high-speed, large capacity and long-distance transmission systems.This paper studies the CO-OFDM single mode fiber system, mainly including the analysis and design of the system block diagram, the system performance of different modulations, the analysis of timing synchronization algorithm and simulation realization. The specific work as follows:First, the theoretical model of the CO-OFDM single mode fiber system is analyzed. In the four modulation schemes of 2PSK,4QAM,8QAM and 16QAM, we analysis the transmission performance for the rate of 10.7Gb/s CO-OFDM single mode fiber system.The results show that the relationship of transmission capacity, transmission distance and BER of the system are contradictory in the same conditions and increase OSNR can improve the system performance to some extent.When BER of the system maintaines at 10-3 or less, and to take 4QAM modulation, when the OSNR of 12 dB, the transmission distance of up to 1600 km, when the OSNR increased to 19 dB, the system's maximum transmission distance of 1900 km.The traditional timing synchronization algorithm of dispersion-sensitive, a new improved algorithm of the training symbol sequence of symbols in the original structure is based on the first one has been added to the OFDM symbol cyclic prefix length of the tail of reproduction on the front of the symbol, that is used as a training sequence, L generally larger than the cyclic prefix length, The phase of replication sequence will be disrupted using the pseudo-random sequence.Its specific structure as follows:[CP2 CP OFDM]. In the same simulation conditions, the Schmidl & Cox algorithm, Minn & Letaief algorithm and the Park & Cheon algorithm and improved algorithm, the 1000 timing points for comparison and simulation to the mean error rate of improved algorithm always maintained below 12% is more suitable for fiber channel.Third, the design of the transmission rate of 107Gb/s of the CO-OFDM single mode fiber system is completed theoretically using orthogonal bandwidth multiplexing(OBM) and 2×2 CO-MIMO-OFDM system model. The designed 2×2 CO-MIMO-OFDM timing synchronization in single-mode fiber system analysis and simulation show that the proposed algorithm in the system is feasible.