Small Cells Expanding Mobile Broadband Network Coverage

With the emergence of smart terminals and internet apps, people are depending more and more on mobile broadband services in daily life. From 2011 to 2012, mobile internet traffic increased 850 percent. As smart terminals become more powerful and LTE networks are commercialized in more fields, mobile data traffic will continue to grow in the future. Therefore, traffic density will be much higher in some regions, and applications scenarios will be more complicated. In this case, even LTE may struggle to meet such demand for data services through only macro cells.
Small cells improve network capacity in hotspots and provide coverage for blind spots and indoor places. Operators predict that small cells will play an important role in future communications. Fundamentally, a small cell must be cheap and easy to deploy and it must accommodate compact equipment.
ZTE’s Pico RRU meets all of these requirements and incorporates a small cell backhaul solution.

Industry Leading Pico RRU Solution
The main challenges in deploying a small cell network are:
● keeping construction costs to a minimum
● reducing impact on existing networks
● saving scarce transmission resources and finding good alternatives
● enabling macro and small cells work together well (interference between them should be considered)
● high-precision clock synchronization and the very high requirement it places on the transmission network and base station installation.
To address these challenges, ZTE has introduced a Pico RRU solution that includes Pico RRU, BBU and P-Bridge. The Pico RRU shares the same BBU resource pool with the macro base station, and the BBU provides baseband resources. The Pico RRU can be flexibly deployed in various scenarios and supports installation modes for blind spots, hotspots, and indoor coverage. The P-Bridge provides cable conversion and connection between the BBU and Pico RRU; it connects with BBU via 10G optical fiber; the P-Bridge allows Pico RRUs on floors or in specific areas to be converged and managed. Through the P-Bridge, the 10G CPRI optical interface is converted into a CAT5 cable interface and connected to the Pico RRU via a CAT5 twisted pair. Because the length of a CAT5 cable is limited, the Pico RRU solution supports P-Bridge relay for Pico RRUs that are relatively far apart. This allows for more flexible Pico RRU deployment.
ZTE’s Pico RRU includes outdoor Pico and indoor Pico, both of which are multimode and support UMTS/LTE/WiFi. The Pico RRU provides indoor and outdoor blind spot and hotspot coverage and improves network capacity and quality.

Advantages of ZTE’s Pico RRU solution:
● A Pico RRU is small, easy to install, and consumes less power. It is suitable for various scenarios.
● P-Bridge connects to the RRU via a CAT5 cable. Existing cables are used, and this reduces network deployment costs.
● A Pico RRU uses a twisted pair for IQ data transmission, which facilitates cabling.
● Pico RRU can use remote power supply. This makes it easier to cable AC power to active equipment. It also makes equipment installation and maintenance easier and reduces cabling costs.
● Synchronization is simple. Pico RRUs and macro base stations can use the same clock for synchronization.
● Interference between Pico RRUs and outdoor macro base stations can be coordinated.

Forward-looking Backhaul Solution
With large-scale deployment of small cells, backhaul network construction will be a major challenge. Small cells and traditional macro base stations place similar demands on backhaul networks. However, small cells create many new challenges to backhaul networks:
● The industry has predicted that the scale of small cell deployment will be nearly 10 times that of traditional macro cell deployment. Using old backhaul network construction methods for small cells will have heavy investment and burden.
● A variety of backhaul solutions are needed for the various small cell scenarios and different network situations of operators.
● Small cell equipment is deployed outdoors on streets, lamp posts, and walls—places where there are probably no cable transmission resources and where it is impractical to lay fixed cables. Therefore, it is necessary to use wireless.
● Small cells are deployed outdoors on a large scale, which involves renting sites and establishing support facilities. These add to the difficulty and costs of deployment.
Therefore, operators need to select backhaul transmission mode flexibly. Available backhaul transmission solutions include packet bearer network, fixed network broadband, WiFi, LTE, and microwave.
ZTE has introduced an integrated backhaul solution in which transmission devices are made into modules and integrated into small cell equipment. This makes network construction and deployment easier and greatly reduces investment and maintenance costs. A DSL module, cable module, PON module, WiFi module, and TD-LTE module can already be integrated into small cell equipment. In addition, outdoor microwave units with antennas can also be combined with small cells.
Advantages of ZTE’s integrated backhaul solution:
● Operators can flexibly select their backhaul solution and are not limited to the traditional packet bearer network. This reduces cost and facilitates deployment.
● Transmission modules are integrated into small cell equipment, which makes network construction much easier. Installation and debugging is simplified, and operator investment is reduced.
● It is unnecessary to lease other sites to accommodate transmission modules. This saves costs in leasing, support facilities, and operation and maintenance.
In the fast developing information era, ever-changing market demands call for continuous innovation. ZTE is dedicated to innovative research and development in TD-LTE. ZTE has invested heavily in small cell research and has introduced industry-leading concepts and solutions. ZTE continually pushes forward the development of mobile networks.