Design And Implementation Of Hardware Circuit On GPON ONU

With the fast development of Modern Communication Technology,the backbone network and local area network of communications network made the huge progress. The backbone network has been turning toward digitized, wide band rapid nearness and the local area network also gradually turns toward the intellectualization, the multimedia directions to develop. However the access network which is the connection link of backbone network and user develops actually slow and becomes the important attribute which is the restriction information superhighway's developed. (PON) the technology has the good market prospect as access network's solution,specially the GPON technology, has become one of the best solutions of professional recognizes.The technical standard of GPON which is drove by the operator needs the comprehensive consideration of operation benefit. ONU is the network equipment which connects the user interface in GPON system. Its technology and cost will influence economy bearing capacity of optical fiber user immediate. And it's the important attribute who affects the development and the application prospect of GPON technological. This article has divided GPON ONU system into physical medium layer,GTC layer,management and control layer to design, specially has made the detailed design of the core level GTC level. The physical medium layer completed the electro-optical transformation by the optical fiber transceiver; The GTC level made low cost's FPGA and the SERDES use together to realize programmable or upgradable low cost ONU and complete the connection with the physical medium layer. It provided the network interface of user to transport the Ethernet /IP service and the VoIP service; The management and control layer is realized by embedded microprocessor, and expanded Flash, SDRAM, RS232 and JTAG in exterior to construct the hardware platform of embedded system. This article established the GPON system by realized product to test its performance such as Throughout, Frame loss and Latency and so on.First this paper introduced the development background of GPON technology, studied the development present situation and the application situation at home and abroad and pointed out the technical superiority and the prospects for development of GPON; Second it analyzed the GPON's architecture, protocol model and the principle of work and the key technologies; Then it proposed function demand and design objective of ONU. According to the protocol model of GPON, ONU divided into the physical medium level, the GTC level and the manage and control unit, and contrasted the realizes plan to choose the best plan, finally proposed the ONU overall design plan; Next it designed the chip's principle of work and the peripheral circuit of 3 functional module; Finally it proved this design proposal accuracy by testing the performance of this system on Throughout, Frame loss and Latency in GPON system established the by the realization product, and summary the design work, and discusses the topic next step work.