The Implementation Of Core Functions Of Embedded Software For EPON System And Study On 40Gbps OFDM-PON System

As "the last kilometer" solution, PON technologies have attacted more and more attentions. EPON is one of the most popular PON technologies, because of the following features:cost-effectiveness, high bandwidth, compatibility with the existing Ethernet and easy for management. As orthogonal frequency division multiplexing technology has the following advantages:supporting high speed signal transmission, good resistance to optical fiber dispersion, flexible subcarrier allocation way, cost-effectiveness after using DSP technical, OFDM-PON system becomes one of the hottest topic of research and the best candidate for the next generation super capacity PON technologies. The paper is supported by the National 863 project "The key technology of dynamic heterogeneous integrated access network supporting P2P and multicasting" and embedded software design and realization of EPON is discussed. The goal of design is either satisfing of the basic function of EPON system or simplifing the design, reducing the cost and supportting comprehensive network management; OFDM-PON system are also researched, the basic theories are studied, and 40 Gbps OFDM-PON system are theoretical analysised and simulated.The major work of this paper is listed as follows:1. The embedded Linux development environment is established which includes transplanting of Linux kernel and the seting up of Linux filesystem. After these, the development work can be implemented on the target board.2. The funcational requirements of EPON system's embedded software design are analysised. The FPGA driver module, PON module and the SNMP Agent module are designed and developed. Functions include:register management of ONU; handling the OAM frame between OLT and ONU; configuration and management of device; statistics of system performance parameter. The development work is based on Linux operating system. Because Linux is a roubust open source system, the development work can be simplified and the cost can be lower at the time meeting the functional requirements of EPON system.3. The features of using OFDM technologies in optical communication domain are studied. A scheme of upstream OFDM multi ple address access which based on downstream broadcasting the optical carrier using in upstream is proposed. A 40 Gbps OFDM-PON system is theoretical analysed and simulated. The simulation results proved that the scheme we put forward is practicable. The scheme can solve the problem of upstream OFDMA of multiple ONUs, and has the potential superiority in cost.