Deploying small cell backhaul in BeijingPublished on July 16th 2014 in News
Wangfujing Street is one of the most famous and busiest shopping streets in downtown Beijing. This largely pedestrianised area attracts an estimated 600,000 visitors on a daily basis, which can rise to 1.2 million during holidays. And most of them are using their smartphones.
When China Mobile launched its TD-LTE network in December 2013, it stated that it expects to provide coverage via 500,000 base stations to around 350 cities by the end of 2014 – an aggressive rollout schedule by any operator’s standards.
Wangfujing Street and the surrounding area is a particularly challenging environment for cellular network deployment. It’s a typical urban canyon with high-rise buildings to both sides, on which the macro network base stations are installed. Despite the higher data rates enabled by 4G, it’s difficult to provide coverage and capacity from the macro network down at street level.
It’s no surprise then that this became one of the first locations for metro cell deployment in China – and the world – to provide optimal 4G coverage to China Mobile subscribers and handle the anticipated traffic load on the network.
CCS was selected to provide the small cell backhaul system. Its self-organising units are located at strategic lampposts throughout the shopping area. Each location consists of a single CCS node together with a single or dual small cell to form a 4G/LTE macro and small cell HetNet. The 28 GHz multipoint-to-multipoint backhaul network consists of a wired hub node located at an existing high-rise macro site, which serves multiple CCS nodes at street level and connects the small cells back into the China Mobile LTE core network.
Once the CCS network has self-organised into an optimal topology, the cluster runs a S-TDMA (Spatial-TDMA) transmission schedule which allows links to operate simultaneously to increase the overall capacity delivered to each small cell location.
To minimise disruption to the network, installation took place at around 2am. Operating in darkness, with temperatures dipping down to -15°C in the middle of winter, speed and ease of installation were particularly important. Luckily for the installer, a local lighting contractor, each CCS node can be deployed in less than 15 minutes. And he didn’t have to hang around up a lamppost to configure or align the antenna. Its self-organising capability automatically did that.
Post installation, the performance improvement was immediate – demonstrating up to 90Mbps download speeds to the handset. The CCS nodes are now live in the network and will continue to be rolled out to connect small cells in the surrounding areas. There is no intention to deploy a blanket HetNet from day one, but rather to grow the network organically. CCS’ backhaul system is particularly suited to this kind of deployment. As each node is added, existing nodes will automatically self-organise and re-align.
In Wangfujing Street today, China Mobile subscribers are now enjoying superfast mobile broadband as it should be.