Investigations And Experiments Of FEC And Corresponding Techniques In XGPON Protocol Analyzer

With the rapid development of the various multimedia services, in access networks, a higher requirement has been raised and focused on network bandwidth, network capabilities of supporting multiple services and advanced network facilities. There are some inextricable technique bottlenecks in enabling the existing access networks to fully satisfy above-mentioned new network requirements in a cost effective manner. Therefore, the establishments of the next-generation of access networks are around the corner.The research and development of XGPON key technology and core equipment is particularly important to promote the application of XGPON technology.Based on the XGPON protocol series, a PON network protocol analyzer capable of synchronously capturing and analyzing the XGPON network protocol frames has been designed in this paper. Special attentions have also been focused on the logic functionalites of physical adaptation sub-layer, especially for the forward error correction techniques (FEC). The specific works are listed as follows:1. The logic functionalities of physical adaptation sub-layer of the XGPON network protocol analyzer have been realized capable of upstream and downstream frame capturing and corresponding analyzing, which includes LVDS receiving, bits adjustment, frames alignment, four-times oversampling, width conversion, frame synchronization and descrambling modules.2. Based on RME algorithm, a forward error correction decoding method has been proposed for XGPON networks to realize the real-time decoding within the FEC block transmission time duration. The main works of this section include syndrome computation, the key equation solver, Chien search and Forney algorithm modules.3. Based on XGPON protocol analyzer, an adaptive FEC scheme has been researched for XGPON downstream communication. According to the observed signal transmission performances in XGPON, the adaptive FEC functions can be dynamically and flexibly activated and/or deactivated on-demand. Making use of such adaptive FEC method, the best trade-off between communication efficiency and quality can be achieved easily by the system.4. The tools and the testing platform finally employed in developing XGPON protocol analyzer are introduced, based on which each module of the physical adaptation sub-layer of the XGPON protocol analyzer has been tested and evaluated.The network protocol analyzer designed in this paper can receive the upstream and the downstream packets simultaneously. After data parsing and correcting process, the messages are repackaged into Ethernet frames and sent to the PC. Throughout the extensively examinations under different application scenarios, the obtained experimental results indicate that the performances of XGPON protocol analyzer has strong stability, and that the transmitted data errors and frame loss are rare after implementing the forward error correction. XGPON protocol analyzer satisfies the actual engineering requirements and is suitable for practical applications.