Research On Key Technology Of Local Optical Transceiver Based On OCDMA

Optical code division multiple access(OCDMA)attracts a lot of attention of researchers and becomes one of the hotspots in the field of optical fiber communication.It is the most promising multiple access technology to achieve the true meaning of all optical communication networks,as it has many advantages such as random access,high spectrum efficiency,high security,and low cost,and moreover,it can overcome the electronic bottleneck.OCDMA is also regarded as one of the best candidates for of next-generation passive optical network(PON).The lack of practically applicable high-performance optical address code,Multiple Access Interference(MAI),the problem of high cost,and the difficulty of implementation and reconfiguration of the codec are the several major technical bottlenecks of OCDMA system at present.These bottlenecks also make the traditional OCDMA system difficult to show its competitiveness in the PON application.That makes OCDMA-PON is still in the experimental stage,and hindering its commercialization process.Therefore,looking for a low cost OCDMA codecs with good reconfigurability and excellent transmission performance becomes an urgent need for commercialization of OCDMA.This paper mainly focuses on the key technology and theory of OCDMA codec of OLT,hardware and software architecture and network management system,so as to seek the further practical idea of OCDMA-PON.1.The present situation of OCDMA technology and PON has been studied and introduced by analyzing;and a PON scheme is given based on electro-optical reconfigurable codec in local node and fixed full-optical codec in remote node.A novel two-dimensional OCDMA scheme and its En/Decoding algorithm are further proposed;and its mathematical model was given.The feasibility and good performance of the scheme has been demonstrated by a system simulation of the rate of 5Gbits/s,two users.The scheme is relatively simple to implement and easy to control in reconfiguration.It can reduce the cost and complexity of equipment,and may have a good application value,and also provide a new idea for the practical application of OCDMA system.2.The hardware and software architecture of the central office optical transceiver based on OCDMA is designed and built.Based on the architecture,a system experiment of the rate of 300Mbits/s,two users is completed.The results of experiment show that the user's signal can be decoded and recovered accurately in a free error level,and validate the feasibility and good performance of the scheme.In theory,if the inhibition algorithm for MAI is further added into the codec and high-performance address is used,the amount of the system concurrent user and system rate will be greatly improved.The single-port downlink rate of OCDMA-OLT can reach 128Gbits/s from analysis.3.The components of network management and network management model has been introduced.This paper analyzed the interactive communication between managerment station and OLT from the aspects of architecture,information model and communication model by combining OCDMA-PON with SNMP protocol.Based on the OMCI protocol,the communication method between OLT and ONU is designed.The network management model of OLT in OCDMA-PON is analyzed and studied;and the network management system architecture of OCDMA-PON is given.The initial software architecture designed in this paper is given;This paper analyzes the interaction communication between management station,OLT and ONU,and finally gives the total flow of OLT system software and ONU system software.4.This paper introduces the construction methods and steps of OLT and ONU system software development environment in detail,analyzes and studies the interactive communication method of network management system on OCDMA OLT.The design of the management information base(MIB)for OCDMA-PON has been completed;The SNMP protocol interaction between the management station and the central office OLT has been realized.SNMP and OMCI protocol conversion function module has been implemented;A functional module of the frame OMCI codec and OMCI frame response has been realized.In general,the Get/Set interactive communication between the management station,the OLT and the ONU is completed.