Application Research And Key Equipment Development Of RFoG Bidirectional Fiber Access System

In recent years,with the continuous development of the world's Internet,Internetderived multimedia services have experienced a geometric explosion,China's broadband speed requirements have also increased.The 100 Mbps broadband speed is already a basic requirement,and the 500 Mbps access speed service has also been brought to market.The Prime Minister's report also mentioned broadband services many times,the report pointed out that broadband services need to increase speed while reducing costs.Therefore,internet broadband access services have become an important research topic.The Cable Modem system has been in service for two-way cable networks for more than 20 years,and is the best solution for the construction of cable two-way service network.Its DOCSIS3.0 standard can provide high access bandwidth of 1.6Gbps downstream and 240 Mbps upstream.RFoG bi-directional fiber access network is an optical transmission network structure based on this system and standard.Using RFoG technology for network expansion and upgrade is the most cost-effective solution among many solutions.This thesis deeply studies the various technologies and standards related to RFoG bidirectional optical access network,and conducts in-depth analysis on the common fault phenomena of traditional RFoG expansion schemes,researches and develops new network upgrade and transformation schemes,and develops development plans for key equipments and completes equipment development.Then the new solutions and key equipment were applied to Fuzhou's existing RFoG network for test and verification,and carry on the data contrast analysis.A set of upgraded RFoG bidirectional fibers technical solutions and application technical specifications of the access network that could be promoted and deployed was summarized.The main work of this thesis is as follows:Firstly,conduct on-site investigation of traditional RFoG expansion system problems.After the upstream and downstream multi-channel bonding function is enabled in the DOCSIS3.0 standard system,the reverse channel SNR and BER value will decrese obviously,resulting in a significant decrease in system stability.One of the main reasons is that the OBI problem occurs in multi-channel backhaul,which affects the reverse signal quality.Another main reason is that the number of broadband users has significantly exceeded the network carrying capacity..Secondly,in response to the above problems,an upgraded version of the RFoG bidirectional fiber access network solution was developed.The first is that each reverse service group selects different optical wavelengths of the CWDM standard,so that even if multiple optical Nodes emit light at the same time,no OBI problem will occur.The second is to reduce the size of the service group to meet the higher penetration of business needs,so that the network is no longer congested.Moreover,detailed technical solutions are formulated for the two structures of FTTB and FTTH,and the technical parameters of the transmitter and the receiver are calculated and specified,so that the network solution can adapt to the deployment environment requirements of large,medium and small cities in China.Thirdly,a new RFoG optical Node was developed to meet domestic application needs and reduce costs.The device to meet the reverse CWDM return wavelength requirements,transmit optical power and coverage capability requirements of the overall solution.The main specfications of the new equipment are better than national standard,C/N≥52dB,C/CSO≥65dB,C/CTB≥70dB,the reverse frequency expands to 85 MHz,which can provide greater reverse bandwidth.Finally,the upgraded access network solution and new equipment will be applied to the site of the Fuzhou RFoG project for pilot operation.After three months of continuous monitoring,the network operation is very stable,the SNR of the reverse signal is increased from 26 dB to over 37 dB,and the BER is fully,which greatly improves access bandwidth,carrying capacity and network quality.The RFoG bidirectional optical Node developed in this thesis is very suitable for new situations and requirements.It will not only be the best solution to promote FTTB for large-scale network transformation in Fuzhou in the future,but also suitable for promotion to cable network using Cable Modem system throughout the country,which has strong scientific research significance and application value.