A Study On Fiber Access And Transport System Based On Synchronous Digital Hierarchy

As developing in the high speed trunk networks, Synchronous Digital Hierarchy (SDH) is now entering the low speed access networks. Researching and developing SDH optical transport system, which is suitable for the local service situation and is used in access networks, is an important trend in the application of SDH. In addition, IP over SDH technique is the hot topic in the SDH research field. Some foreign companies and institutes announce that they have succeeded in designing the IP interface equipment, but the core technique is still closed to the public. In this thesis, I will analyze and study the key technical problems meeting in the two research directions. It includes contents as follows: Research and develop a new kind of high quality SEC for SDH system. We provide the optimal principle for designing the Phase Locked Loop (PLL), which is the core component of SEC, and design an optimal Digital PLL (DPLL) with very narrow bandwidth. The SEC containing this kind of DPLL can adjust the phase acquisition speed and precision adaptively. It tracks the timing signal of 155MHz line directly and resolves the network synchronous problem during applying SDH in access networks. The SEC has been used in the SDH optical transport system (155MHz) of Datang Telephone Co. Ltd successfully. Provide a new scenario to reduce the pointer adjustment jitter named adaptively modulated bit leaking. It adopts a novel phase spreading principle and carries out sequence modulation to the leaking of per bit. Therefore, the phase leaking is removed from the low frequency band to the high frequency band effectively, which makes leaked phase to be filtered by the PLL easily. Compared with previous scenarios reducing the pointer adjustment jitter, it greatly improves the ability to suppress the jitter generating in the SDHIPDH network edge and ensures the service quality when SDH technique is used in access networks. Provide the network organizing method and protecting strategy for SDH access networks. On the basis of studying the reliability, survivability and the cost of SDH self- healing networks, we certify the advantages of using U-SHRI2 loop topology and corresponding protection manner in SDH access networks. At the same time, thesurvivabiIity quanitative analysis for SDH access networks is helpful to forecast andevaluae the ability against damage. These researches are significan in designing andmaintaining SDH access netwOrks. Research and develop the SDH optical transport system used in accessnetwOrks. We provide the design of the core network elemellt of SDH opticaltrAnsmission systeWep multiplexor (ADM), as well as the design for the crosscotmection matrix chip with property right in ADM. We comPletely test the tecImicalparameters of the system. The testing results show that our SDH optical transportsystem has excellent performance. Research and develop a kind of IP over SDH wide band access server. On thebasis of studying the corresponding protocols of IP over SDH, we provide a novelscenario for designing IP over SDH wide band access system, and develop the daretransfer algorithrn of the key comPonent of the systemopacket switch router engine.Furthermore, we design the packe switch router engine based on FPGA and it fills thetechnical empty in China. Traking the research abollt IP over WDM optical Intemet tCchnique. On thebasis of studying another novel trAnsport techniqueWaVelength Division Multiplexing(WDM), we discuss the aPPlication of IP over DWDM technique in the optical Intemetof the fuure. We focus on studying and tracking the key techniques and development ofIP over WDM, which is an Intemet resolution scenario...