High-speed access multidimensional reuse and coherent technology flourishHigh-speed access multidime
The rapid development of the Internet, microblogging, micro-channel, online games, virtual communities, HD video, e-commerce, online banking and other rich applications and services have been fully integrated into the daily lives of the public. Internet service operators network bandwidth, fine and differentiated service requirements have become increasingly prominent and urgent.
Meanwhile, with further promote the "broadband China" strategy, operators will focus on developing ultra-broadband Internet access, mobile Internet access, cooperative communications, multiple concurrent HD IPTV, integration of video communication, remote video and control class of business, 3D rich media, cloud computing / cloud storage, networking and other new business.
It said data communication needs of different network environments for growth can be interpreted as the demand for bandwidth. At present, because of network bandwidth bottleneck, there is not enough bandwidth to support the growth spurt data needs. In order to improve the network last kilometer access bandwidth of high-speed optical access technology is introduced.
Typically, improve PON access network bandwidth in two ways: Single lifting rate, increase reuse dimension. Single-channel rate increases bandwidth and improve, but should be considered high-speed optical signal nonlinearity, dispersion and receiver sensitivity decline and other factors, but also concerned about the support of high-speed electrical devices in the electrical domain. Multidimensional reuse is an effective way to improve access bandwidth, the current optical communications technology division multiplexing dimension has, wavelength division, code division, frequency division and mold classification, in PON networks can use the previously mentioned dimension, to improve the capacity of the network. From the access network PON technology development, through a single dimension to multiple dimensions to enhance the bandwidth of the network. The first generation of PON technology, EPON / GPON downlink broadcasts uplink single dimension of time-division multiplexing, which provides 1G / 2.5G access bandwidth; 10G EPON / XGPON division of a single dimension, by increasing the rate of single-channel 10G rate reached to provide access bandwidth; second-generation PON, namely NG PON2, on the basis of 10G PON division rate, an increase of wave fractal dimension, which uses time-division, two-dimensional wave-division multiplexing to 40G TWDM PON is represented with four wavelengths, each wavelength 10Gb / s rate PON network capacity will increase to 40G, can be increased to eight wavelengths, capacity up to 80G. That is the next generation of PON NG PON3, is expected to be NG PON2 basis, to enhance the single-channel rate, enhance the capacity of PON access network again.
EPON / GPON, 10G EPON / XGPON standards have matured, have large-scale or small-scale commercial application in the market. 40G TWDM PON will gradually improve as the NG PON2 series of standards is expected to start commercial tour in five years. Other patterns reuse industry research focus is to OFDM as the representative of frequency points to OCDMA represented by code division, as well as recent academic research active mode classification. Reuse through more dimensions, the greater the ability to enhance access PON network.
In addition, the future government and enterprise customers, end users will need exclusive community wavelength home, and there will be long-distance high-bandwidth and low latency access requirements under part of the scene. Existing technology can not meet the receiving end needs, based on coherent technology PON would be one solution to. T bits based on coherent technology access technology, at the receiving end using coherent reception mode. Capable of carrying more than 1000 wavelengths in a single optical fiber, each wavelength 1G / 10G, passive transmission distance of 100km. Application of this technology can provide greater bandwidth, lower latency access services for users, providing an efficient and low operation and maintenance costs of network operators.
Based on the above, high-speed access technologies multidimensional reuse is a hot research, based on coherent reception of T bit capacity access technology is one of the trends of the industry.