ITU-T G.metro technology for urban low cost multi service access, application scenarios, including mobile prequel, Mobile Backhaul and enterprise leased line, high-end fixed broadband access, can provide direct light to the RRU/ base station / desktop / user, achieve high bandwidth service wavelength level, has been widespread concern in the industry.
Since the Chinese Unicom since April 2014 to take charge of the G.metro standard, discuss the network research institute combined domestic and international mainstream industry equipment suppliers and chip optical module suppliers actively carry out G.metro standards and the corresponding equipment R & D, the German ADVA company to actively participate in the formulation of standards and prototype of product development, the latest research articles to China Unicom demonstration prototype and jointly promote the development of G.metro standard and industry chain.
In late July 2016, Chinese Unicom Network Research Institute jointly ADVA company of Germany Unicom Network in subject city and Tianjin carried out a laboratory test and verify the G.metro equipment for mobile prequel application, good operation effect, have obtained unanimous approval.
ADVA latest prototype equipment features include:
HEE (end connected to a wireless BBU device) and TEE (RRU terminal connected to a wireless device) using DWDM wavelength single fiber bidirectional optical link 100 GHz channel spacing, the highest single support system 40 wavelengths, each wavelength supports up to 10 Gbit/s rate, no light amplification can support 20 km distance transmission case;
The TEE end uses the wavelength tunable optical module, according to the connection of the DWDM port for automatic wavelength adjustment, HEE end without the need for TEE wavelength configuration;
Under normal operation of the system, the wavelength of each TEE is dynamically tracked and locked by the HEE, so the wavelength tunable optical module of the TEE end does not need expensive and complicated wavelength locking function;
All of the TEE wavelength adaptive adjustment and locking function only through the HEE side of a single central control module, greatly simplifies the design of the TEE side, reducing costs.
Main test and demonstration:
In Chinese Unicom subject City laboratory test, demonstrated the transmission of mobile episode CPRI signal of the system (option3-option 7) performance. The inherent system of one-way delay of 130 ns; 15 hours of continuous testing was carried out in 15 km fiber transmission distance, maximum bidirectional delay jitter is 2.3 ns (high precision CPRI TX300S VeEX analyzer test business with atomic clock based on CPRI), and long time business operation of zero error code;
At the same time, the CPRI (1GbE) is tested and verified, and the performance is good for a long time, so it can realize the integration of fixed access service and mobile access service;
In the laboratory wireless test environment, the system is connected to the commercial BBU and RRU link (Zte Corp), and carries out the FDDLTE service transmission test. The test results show that the system has no influence on the wireless performance of FDDLTE;
In the laboratory tests on the basis of the system in Tianjin Unicom Hebei Branch Yue Wei Road branch on-site testing, access to a network in the actual operation of the FDD substation room LTE (HUAWEI), the test results prove that the performance of the wireless system of FDD LTE room has no effect.
Using a wavelength tunable laser, WDM port configuration and management of wavelength independent, eliminating a large number of remote TEE equipment, greatly reduce the maintenance burden, convenient operators for network management, but also greatly reduce the types of operators of spare parts;
By the end of bureau (HEE) focused on the sharing of design type wavelength locking function, the distal (TEE) greatly reduces the complexity and cost of wavelength tunable optical module, thereby reducing the overall cost of deployment of G.metro system, which in the Metro multi service integrated access and future 5G network to large-scale application deployment and cost sensitive background it is particularly important;
The prototype system has fully verified the feasibility and stability of the technical scheme specified in the G.metro standard;
The test results show that the system has been able to be compatible with the actual commercial wireless devices, which is a step closer to the final commercialization.