Investigation On Coherent Reception Dsp Algorithm And Other Key Techniques In Coherent Optical Burst Transport Networks

Based on ring topology, Optical Burst Transport Network (OBTN), which uses optical burst as its switching granularity, is able to adapt to the bursty IP data services and has been researched widely. With the increase of network capacity requirements, reducing the transmission cost of every bit and promoting the network capacity of OBTN become one of the main development trends of optical metropolitan area transport network. PM-(D) QPSK Coherent Optical Burst Transport Network (COBTN) which combines the coherent detection, multi-level modulation and polarization multiplexing technologies, has high spectrum efficiency and is easy to improve the system capacity. Due to its excellent wavelength selectivity, coherent detection is easy to implement the tunable reception with different wavelength in OBTN and build optical metropolitan area transport network flexibility. COBTN becomes one of the important development trends of optical metropolitan area transport network and will be put into application in the next few years.This dissertation focuses on the key technologies of OBTN, especially for the Dynamic Bandwidth Allocation (DBA) algorithm and optical burst coherent reception DSP algorithm. The main contents of the dissertation are as follows:1. Based on Fixed Transmitters and Tunable Receivers (FTTR) wavelength tuning mechanism and centralized resource scheduling scheme of OBTN, we propose a DBA algorithm which can effectively solve the collision problem in OBTN and realize the flexible allocation of bandwidth resource. The simulation results show that the proposed algorithm can significantly reduce the network packet loss rate, decrease average delay of packet, and increase the bandwidth utilization with24.3%under no packet loss, compared with the static bandwidth allocation.2.Since the optical bursts carried by different wavelengths may go through different optical paths, the impairment they experience may differ greatly and change over time. We design a coherent burst-mode receiver structure combined data-aided with CMA blind processing, which can quickly adjust the parameters of DSP algorithm for the bursts with different damage and improve the convergence speed of adaptive equalization and polarization division de-multiplexing algorithm by optimizing the initial value of tap coefficient. The simulation results show that the coherent burst-mode receiver structure can improve the convergence speed by more than50%.3. Since transient frequency offset from wavelength tuning exists in the COBTN which uses the fast tunable laser to complete the coherent reception, we design a coherent burst-mode receiver structure based on data-aided. The structure can further reduce the overhead of the burst through making the valid data be transmitted during the transient effect. The simulation results show that the coherent burst-mode receiver structure can reduce the overhead of the burst by50%.