Gpon System Tdm Access Technology

Beacause APON's efficiency is low and EPON could not provide quality assurance for real-time services, network inspection, operation management and network control, GPON was proposed by FSAN in September 2002, which can provide gigabit speed, high efficiency, transparent transmission of multi-services and specific quality of service.At present, the GPON standards, G.984.1, G.984.2, G.984.3 and G.984.4, have been established by ITU-T. They describe the architecture and functions of the whole system. The thesis firstly studies these standards and analyses the transmitting process in GPON. As the system can provide rather high speed, it can satisfy the demand of broadband. But nowadays, the TDM services are also very popular, so GPON need to support TDM services. GPON has just come on the market, the researches on this system are under way. So it is very useful to study this access method. The thesis will focus on TDM access method. After analyzing the standards and reviewing the theory of circuit simulation in EPON, a scheme will be given to TDM access. And the details of OLT and ONU to transmit the TDM services will be described.GPON is multi-point to point network topology structure in upstream direction. In order to transmit TDM services, besides the common modules such as DBA, FEC, AES, the system also need data adjustment, clock recovery, and so on. Clock recovery is an important and difficult part of TDM access, so the thesis will emphasize on it. And two methods of clock recovery are proposed in the thesis. In the last part of this paper, simulation is given to show the performances of the clock recovery methods. The results prove the good jitter performances of the methods.