The addition of more carriers and sites is the traditional method to increase network capacity. However, as the number of sites increases in a specific area, interference also increases accordingly, and therefore undermines the expansion capacity and user experience at the cell edge. At the same time, the popularity of services such as HD video has placed higher requirements on the user experience.
The Bund is a famous scenic spot of Shanghai and its particular location features ultra-high traffic density and wireless network coverage difficulties. In 2015, China Mobile Shanghai, pioneered deployment of Book RRU on public surveillance poles, successfully was overcoming site acquisition issue in densely populated areas and scenic spots, and greatly improving the 4G network experience in the Bund area. However, public surveillance poles impose restrictions on the network topology and increase the coverage overlap between sites and co-frequency interference. The average SINR measured during drive tests was only 12.4 dB and the average downlink rate was 32.7 Mbps.
This innovative D-MIMO solution proposed jointly by Huawei and China Mobile has been widely acknowledged by operators as one of key technologies of 4.5G and even of future 5G networks. During the commercial use trial, China Mobile adopted Huawei CloudRAN networking solution by reusing the baseband unit and RRUs on the live network and enabling BBU sharing among RRUs. Then, merely by upgrading the base station software, the operator successfully enabled the D-MIMO solution. All relative efforts were completed in the equipment room, without the need for site visits.
The result of the test using commercial 4G mobile phones denoted that the cell capacity increased by 35% to 140 Mbps, in comparison to the 103 Mbps capacity achieved through cell merging, after D-MIMO was enabled. The average cell throughput increased by 45% from 45 Mbps to 65 Mbps, with the user rate at the cell edge increasing by 80% to 15 Mbps.
Traditional network construction is network-centered, and user experience tightly depends on the network planning and design. Strong interference and weak coverage inevitably affect the user experience. The new D-MIMO solution is not subject to the network topology, greatly reducing dependency on network planning and optimization, and allowing user-centric network construction. China Mobile Shanghai will continue to promote the maturity and commercial deployment of 4.5G and even 5G technologies to build the world's leading TechCity in Shanghai.
Xu Xuebing, General Manager of Huawei TD-LTE domain impressed,”Huawei makes great efforts in developing innovations and exploring technological evolution in the field of TDD. By adopting 5G technology on 4G networks well in advance, operators can transform interference into useful signals, resolving challenges brought on by dense site deployment. This can also transform traditional base station-centric networks into user-centric networks, providing end users with a no edge MBB experience.”