Hardware Design And Achievement Of GPON Systerm

In recent years, with the rapidly developing information and technology, dataservices are rising. The kind of telecom has been extended from simplex telephonEtelegram to several services.The backbone network of telecom has changed verymuch, but access network has been the bottleneck between backbone network andhigh speed LAN .Technology for access networks that is inexpensive, simple,scalable, and capable of delivering integrated voice, data, and video services to anend-user subscriber over signal network is required.So PON technology is born. PONtechnology has come through APON,BPON,EPON and GPON severalphase. GPON is put forward by FSAN in September 2002, with gigabit speed, highefficiency, beating multi-service transparent transmission, supplying specific qualityof service, service level, network inspect and operation management. It can work atmaximal speed of 2.488Gb/s.The GPON adopts network topology of one-to-multi-point and passive firbletransmition mode topology, and is constituted by OLT, ODN and ONU.OLT transmitsdata frame via ODN from OLT to ONU in broadcast mode. Different ONU adoptsTDMA access technology in upstream direction. The ONU sends the data frame whichis inserted to different time slot to OLT.《General characteristics for Gigabit-capablePassive Optical Networks》mostly prescribe the GPON network parameter, theprotection switching function,interface type and operation type.《TransmissionConvergence Layer for Gigabit Passive Optical Networks》mostly prescribe GTCOverview,GTC TC frame structure and activation Procedure in the ONU.The quality of PCB design is concerned about the achievement of this design,SOthe design of PCB is one important tache of hardware design.Penman research PCBarchieve from impedance matching, the layer of PCB and signal integrity.It isregarded as the last and optimum PON to point network topology structure inupstream direction. Different ONU adopts TDMA access technology in upstreamdirection. GPON OLT adopts broadcast access technology in downstream direction.In this paper we introduce the ranging method and delay compensation of standardG. 984. We introduce the systerm structure of GPON,work theory of GPON andstandard protocol of GPON.In this paper, the keystone is the hardware design of GPON OLT systerm.TheGPON OLT systerm is divided into three parts: CPU systerm unit,GPON access unitand GPON Transmission Convergence uinit.We discuss the detail of hardware designin chapter 3.This design can be implemented properly, because it is the improvementof one design which has been achieved.The quality of PCB design is concerned aboutthe achievement of this design.We discuss that how we can design a perfect PCBfrom three facets: impedance matching, the layer of PCB and signal integrity, in thelast chapter of this paper.