Qcell: Helping Operators Provide Indoor Coverage

According to the ITU, 70 per cent of all mobile voice connections and 80 per cent of all mobile data connection occurs indoors. Indoor coverage is a huge part of future wireless development. However, in the 4G era, deep indoor coverage is difficult because networks are extremely complicated and are operated in different scenarios. Deep indoor coverage creates challenges for operators:
●   High LTE frequency bands increase free space loss, penetration loss, and feeder loss.
●   The three types of cellular network—2G, 3G and 4G—need to be converged in a cost-effective way.
●   Products need to be easy to install and provide good coverage.
●   Networks need to be easily expandable and have high capacity.

Qcell: New-Generation Digital Indoor Coverage Solution

Recently, Chongqing Unicom and Sichuan Telecom built their own next-generation digital indoor coverage systems that address the issues related to indoor coverage.
Chongqing Unicom deployed an indoor 4G network in SM City Mall, a high-end commercial center in Yubei district, Chongqing. The network makes use of ZTE's Qcell system. In a testing, the peak indoor rate was 149.6 Mbps and the peak uplink rate was 49.2 Mbps. According to on-site users, HD videos and on-demand HD movies were played smoothly on smart phones, and large data file download and other FTP services could be completed at an extremely high rate.
Coverage area of the 4G network in the SM City Mall reached 150,000 m², meeting the criteria of China Unicom for class-A scenarios. Performance and capacity of the network were also up to the standard for hotspot coverage. ZTE's Qcell indoor coverage solution provides high capacity and performance and is easy to implement. The digital indoor coverage system was deployed for only one week, covering the entire SM City Mall. Its deployment is far less difficult and complicated than that of a traditional distributed indoor antenna system.
Sichuan Telecom has also commercially deployed its Qcell indoor coverage system that provides 4G carrier aggregation. The acceptance tests have shown that in an indoor area of 10,000 m², when the 1.8 GHz frequency with a 15 MHz frequency bandwidth and the 2.1 GHz frequency with a 20 MHz frequency bandwidth are used, the highest 4G traffic rate can reach 3 Gbps. This means the rate for each user can be maintained at 3 Mbps when 1000 users are using 4G services simultaneously in the area. CDMA voice quality is quite good, and the EV-DO peak data rate is on a par with that of a traditional solution. The system provides 2G, 3G and 4G services that can reach peak rates simultaneously. This enables operators to implement traffic management strategies. Sichuan Telecom was very satisfied with the acceptance tests.
In May 2015, ZTE and China Telecom were jointly awarded the Wireless Network Infrastructure Innovation award for their close collaboration on the macrocell-small cell coordinated Qcell digital indoor coverage system at the Global Telecom Business (GTB) Innovation Awards 2015. In June 2015, the Qcell digital indoor coverage system also won the Best Innovation in Heterogeneous Networks award at the LTE World Summit organized by Informa.

Qcell: Small Size and Large Capacity

The Qcell indoor coverage system consists of Pico RRU, pBridge and BBU. Pico RRU supports FDD LTE, CDMA, UMTS, and TD-LTE. It is small, high-capacity, attractive, and easy to install.
pBridge provides power over Ethernet (PoE) and data compression. It enables LTE carrier aggregation and CDMA networks through a single UTP cable. Another advantage of Qcell is that it can merge or split cells so that operators can adjust network capacity and distribution as required. The system takes into account the future business development while reducing initial investment. Therefore, it can adapt to development in the mobile internet era.
Compared with traditional indoor coverage solutions, Qcell significantly shortens the construction period. Usually it takes four workers one week to install, debug, and optimize a Qcell system in a campus dormitory of 50,000 m².
By using standard Ethernet cables for Pico RRU networking and power supply, the new-generation Qcell carries 2 × 20 MHz LTE cells through an Ethernet cable and can be combined with UMTS, CDMA, and other wireless systems to simplify the deployment of multi-mode indoor networks.
Qcell can share one network management system with 4G macrocells. Each node is visible, manageable, and controllable so that network O&M costs can be significantly lowered. Qcell uses indoor and outdoor cloud collaboration technologies to eliminate indoor signal leakage and outdoor signal interference and to finally optimize performance of the entire network. Qcell can also provide precise local access and indoor location based services to expand business and attract new users.
Network operators in China are in a critical stage of transition from 2G and 3G to 4G. Qcell not only supports rapid deployment of 4G networks, it is also compatible with existing 2G and 3G systems. When all 2G and 3G users transit to 4G in the future, Qcell can evolve existing 2G and 3G networks into 4G through software upgrade. This will protect operator investment. This is also particularly important in the current transition, where VoLTE has not been completely built and voice can only be carried through 2G and 3G networks.
    Qcell is favored by customers for its superior performance. It has been used in more than 20 cities and regions in China, and the total shipment has reached several tens of thousands units.