Base Station  Passive WDM System Solution

Background and Demand

The existing Mobile backhaul networks usually adopt SDH, PTN and MSAP modes to establish the ring network, so as to provide transmission channels for 2G/3G/LTE service. Independent optical fiber core resources are used for the networking of various services.

With the large-scale deployment of 4G networks, a lot of RRU needs to be connected with BBU by optical fibers. However, each RRU requires optical fibers with at least 2~6 cores to transmit high-speed data. The large demand on fiber cores has created huge pressure on optical fiber resources which have been almost exhausted.

Meanwhile, new base station has become increasingly difficult to obtain. It is difficult for residential communities to  install a traditional macro station.  It increases weak coverage areas and the process of installing new fibers is long making, the construction and procedure cumbersome. As a result, it can not meet the requirements for rapid networking of 4G network.

Solutions

Aiming at the above-mentioned problem, Sino-Telecom released a passive WDM solution, which can fundamentally solve the problem.

(1) BBU/RRU Serial Network

If there is a long distance between BBU and RRU, the optical modules at BBU and RRU sides need to be replaced to SFP modules. Moreover, MUX/DEMUX units need to be deployed at both the ends.

The scheme is mainly used in scenario when remote RRU are centrally located. Moreover, only 1~2 optical fiber cores are needed  between BBU and RRU.

(2) BBU/RRU Long-distance Transmission

This scheme is used when RRU are located irregularly. OADM needs to be configured near RRU side.

Successful Cases

Large-scale commercial application of Sino-Telecom’s Passive WDM products and solutions have been deployed across China domestic market. For China Mobile, the products and solutions have been in large-scale deployment in many provinces.

The following figure shows the network schematic diagram of China Mobile Liaoning Branch deployed by Sino-Telecom. The problem of shortage of optical fiber resources of the sites in Dalian has been effectively solved by using Sino-Telecom’s passive WDM system. Moreover, it speeds up the RRU deployment, achieves rapid expansion of base stations, as well as greatly improves user satisfaction.