EE takes step into Parallel world with integrated small cell-backhaul rural deployment

EE is using small cells that mesh in unlicensed spectrum, connected back to macrocells via a new element. But what else can the technology, with its support for virtualised signalling and interface interworking, provide for the operator?

EE has announced it is trialling the use of technology from Parallel Wireless, a company that came out of stealth mode only a few short weeks ago, to provide wireless coverage in hard to reach rural areas. The statement was released last night and embargoed until this morning so you can now read EE’s press release on most of the mainstream tech and telco sites.

EE Commission, Sebergham - 27 Nov 2014

NOW UPDATED: Essentially – new small cell and SON/signalling node player, Parallel Wireless is providing its Converged Wireless System to EE. This sees three to four meshed small cells connect back to a macrocell via one cell that acts as an integrated wireless backhaul node. Wireless backhaul is carried in-band in EE’s 1800 MHz LTE spectrum. The Access Controller also configures and optimises the small cells. The small cells themselves mesh using a direct link in unlicensed spectrum.

Using a small cell in a rural environment, connected in some way back to an operator’s core network, is not a new idea. Just in the UK alone Vodafone has been running a rural small cell programme that connects open femtocells – its Rural Open Sure Signal programme. BT too has looked into the idea. And three years ago it was start-up microwave vendor Bluwan conducting its own trial deployments  in Cumbria, with its Fibre Through The Air solution. As recently as July this year the company was still proposing its millimetre wave solutions as a backhaul option for rural small cells that might overcome rural notspots.

What is different about Parallel Wireless’s solution? Well, for one thing this is an all-in solution. What Parallel Wireless does is bundle up the backhaul with the access in the same box and then controls the connection back to the macro with its controller node –  which is essentially a proprietary node that is not specified in 3GPP LTE standards, but acts as an intermediary on the S1 interface between core signalling and control elements, and the RAN. The access controller also handles the interference mitigation and co-ordination elements for the small cells, and although it’s a unique solution from Parallel it can handle X2 mediation – which is the interface between LTE RAN nodes that requires support for inter-operator small cell-macro cell interoperability.

In this deployment, one small cell requires line of sight so that it can “see” the main 1800 LTE site, which is about 6km away. This then meshes with the other cells, which are down in a valley that was previously a complete notspot. In theory the small cell to macro connection could, with a couple of hops, be as much as 30km.

So what are the questions? Well, first, what of scale and capacity on the backhaul? If you take a Point to MultiPoint solution like Bluwan’s LinkFusion 2, its claim is that one of its main backhaul nodes can aggregate up to 80 channels, supporting 640 small cells and remote sites. Parallel Wireless’ is a different configuration entirely – just a few small cells, a few dozen dwelling perhaps, connected back to a nearby macro site using in-band spectrum.

Another question – what is the real world experience going to be in terms of access speeds and latencies? The EE press release for the launch suggested that with 3-4 meshed nodes, the system can support somewhere between 100-150 “buildings”. An EE spokesperson said that the first benefit has been to bring 3G voice to an area that previously had none. In terms of in-home broadband, by using an access point connected to the LTE small cells, users in trials have been getting 25-30Mbps home broadband connectivity. With more users, that should still be around 15Mbps, EE said.

Finally – the LTE Access Controller – giving as it does the promise of multi-vendor SON and macro-small cell interoperability may be interesting for EE in a number of other scenarios. Does EE see itself exploiting this technology still further?

Well, one thing we have learnt is that EE has an exclusive deal with Parallel for the use of its technology in the UK, and seems very enthused by the company. A spokesperson said, “It is not often you see an operator so supportive of one vendor. The technology is great.”

That said, EE still sees dense urban small cell deployments for LTE as some years off, and for now will be using Parallel “definitely just for the rural use case”.

Parallel Wireless is certainly pushing a fair few topical buttons – including NFV in the RAN (virtualised S1 interface etc) and SDN for backhaul. Not only that, it is taking advantage of recent SoC developments to source full baseband functionality for its small cells for less than $100 – giving its CS100 small cell a decent price point for operators.