System Scheme of Base Station Passive Wavelength Division
October 26, 2020
Networking problem: Heavy consumption of optical fiber.
The BBU-RRU long distance transmission mode is the mainstream of wireless base station construction, and the further centralized deployment of the BBU is the trend of 4G/5G technology development. By reducing the construction of the terminal machine room, the centralized deployment of the BBU greatly reduced the rental cost of the equipment room construction, the cost of the transmission backhaul network, and the daily operation and maintenance cost. At the same time, it also takes a lot of consumption of forward fiber optic cable of terminal access layer.
At present, some base stations are faced with the problem of insufficient optical cable resources. Not only new cable cost is high, but the construction cycle is relatively long, which cannot meet the construction needs. Some of the base station optical paths adopt externally rented optical fibers, which makes it more difficult to expand.
1、Passive WDM scheme:
The transceiver optic wavelength of each channel is staggered by the color light module，and multi-wavelength signals are combined into a fiber core for transmission by using a combined splitter;
Using six wavelength channels from 1271 nm to 1371 nm;
Passive operation, no additional fault points for easy operation and maintenance;
Quick install, no need to debug, no power supply, plug and play;
Compatible with various speeds below 10G and arbitrary protocol services, with strong versatility.
2、Extended application scheme:
Single-fiber four-way bidirectional service transmission is realized by using eight wavelengths from 1471 nm to 1611 nm;
Passive operation, no additional fault points for easy operation and maintenance, quick install, no need to debug, no power supply, plug and play;
Can use 3.5G rate optical module to complete the multiplexing of low-speed interface services such as 4G at a lower cost;
Also used for 40KM long-distance transmission of 10G rate interface (10, 20KM for 1271nm~1371nm window).
The RRU is connected to the network. The BBU and the RRU are in the 1:3 configuration. Each RRU occupies 2 cores. The 3 RRUs occupy 6 cores.
After the passive WDM scheme is adopted, the CPRI signal of the three sectors is converged from the BBU device side through the passive expander at point B, and then becomes a 1-core optical cable to out, which is transmitted to the RRU side. Separate the signals of the three sectors through the same passive expander. And finally connect the jumpers and the RRUs to easily achieve 1:6 expansion