With new construction and expanding capacity, the whole network structure is becoming increasingly complicated. Some equipment has aged and it is becoming increasingly difficult to improve the network, supply new services and improve efficiency. China Mobile Communications Corporation Sichuan Branch ("CMCC Sichuan") choose Huawei with the rapidly and high-quality network adjustment solution successfully completed the world's largest network adjustment project in Chengdu.
Challenge for a smooth evolution to future
Chengdu is the capital of Sichuan Province, the political and economic center of southwest China. With the rising expansion of Chengdu GSM network and continuous development of data services and other new services, a significant problem is the massive consumption of equipment rooms and other auxiliary resources by the original network equipment and the incapability to support new services.
To break network development bottleneck, CMCC Sichuan has deployed and implemented the network adjustment project, and expects half-year network upgrade to establish a future-oriented network, to provide the foundation for the coming 10 years.
The Chengdu GSM network upgrade project involves 1,476 BTSs replacement, more than 14,000 carriers' capability expansion, EGPRS upgrade, indoor coverage, and other engineering. So far, it is one of the world's largest and most complex network adjustment projects with the shortest construction period. The project covers Chengdu major high traffic density area, including the High-Tech Zone, Convention & Exposition Center, Air Port, University District, etc. The synchronous on-line extensive network replacement, capability expansion, new construction, and entire-network EGPRS fulfillment in a short time further add to the difficulty of project implementation.
An Outstanding Network based on Innovation
Constant innovation in technology and management contributes to smooth implementation of a super massive project.
Chengdu GSM network has large scale, and covers many important areas, the risk of replacement become higher then before. CMCC Sichuan utilizes Huawei's mirroring lab located in Shenzhen to completely simulate each step of network adjustment. After successful verification, CMCC Sichuan implants to the existing networks, fully ensuring that project migration is complete at one stroke.
There are thousands indoor sites in the project, so realizing indoor and outdoor cooperative coverage, especially for high buildings, presents a difficult issue as regards network planning. The 155-meter-high Shangri-la Hotel in the center of Chengdu is surrounded by plat low-rise residential quarters; the rooms on high floors receive signals from over 30 cells simultaneously, thus causing disturbing interference. CMCC Sichuan and Huawei determine in consultation to adopt indoor and outdoor frequency separation, enhance room coverage by outdoor uptilt antenna, take priority in ensuring indoor coverage, and prevent frequent handover among high floors to ensure the hotel coverage effect. In view of complicated wireless environments in Chengdu, Huawei adopts the U-NET tool (AFP) and interference matrix technologies to perform automatic frequency planning, by which the veracity and accuracy of frequency planning is improved by nearly 8%, doubled the network capability while the network quality remains at the ori inal network level.　
According to the network planning, Huawei's EnerG new-generation GSM dual-density BTSs were widely deployed in Chengdu. The new-generation GSM dual-density BTS adopts advanced technologies such as transmitting diversity, high receiving sensitivity, and 4-way receiving diversity. Compared with traditional BTS, Huawei's EnerG new-generation GSM BTS coverage is increased by around 40% while the number of the sites can be reduced by approximately 30%.