Halfway through their Cornish next-gen mobile broadband trial, BT and Everything Everywhere have demonstrated that sharing LTE infrastructure and radio spectrum works - and that they might even be able to make it pay.
The companies worked together to install Long-Term Evolution (LTE) tech into two base stations, and supply 180 Cornish villagers with broadband 'net access. Half of them went mobile with USB dongles on laptops, while the other half got in-home hubs providing Wi-Fi-based access. But despite using the same radio frequency, and the same base stations, the two halves of the trial were in fact on entirely different networks, which is rather the point.
The base stations were built by Nokia Siemens Networks and Huawei to demonstrate interoperability. Both cells carried both networks, using the LTE standard to balance (or prioritise) the traffic between the two. The networks share backhaul, over BT's fibres and into the company's 21CN cloud, but are then split out for delivery to Ipswich (for BT's hub-based network) and Bristol (for interconnection with EE's network).
The result is two companies running entirely separate networks, over the same infrastructure and using the same radio spectrum, but without (necessarily) being in competition as they can offer separate services (mobile and fixed internet access in this instance).
This is possible thanks to the huge flexibility of the Long Term Evolution (LTE) which can prioritise packets by user or even application, paving the way for much more innovative pricing as well as reducing the cost of the network by sharing the expense.
Time to lay your hand: What's the business model?
All business models are on the table at this point, including some innovative ideas that LTE makes possible. The team demonstrated how easily an LTE network could prioritise a video stream, at the cost of other network traffic, and while tariffs weren't discussed it's obvious that one might decide to pay for such prioritisation services.
EE told The Reg that, in addition to sharing the investment costs, the infrastructure installed as part of BT's "Super fast Cornwall" project made this LTE collaboration attractive - but similar setups may not be quite as appealing or even possible in other areas.
Neither company involved in the trial is expecting LTE to replace ADSL or fibre services: the focus here is to deliver better bandwidth to people who can't get a decent fixed internet service. It wouldn't be practical to build an LTE network for just those people, but by piggybacking on network built for mobile users it could become economical.
Equally, a 4G mobile network may not be viable in rural areas, even allowing for the greater range of the 800MHz band, but subletting that infrastructure for fixed provision might tip it into profitability.
This trial was to see if such a sharing arrangement was technically possible, and it turns out that it is. Access is currently capped at 8Mb/sec, which turns out to be preferable to a less-reliable connection at 16MB/sec, but the trials have shown that LTE is able to deliver decent speeds right up to the edge of the cell site, somewhat to the relief of all involved.
Latency is also much better than earlier generations of mobile connectivity. On the live network we saw ping times varying between 68ms and an impressive 38ms, on different machines at different times, but still fast enough for cloud gaming and certainly competitive with fixed internet access.
The cells weren't heavily loaded by the 180 trialists, though the companies did point out that the geography of the trial meant that only one sector (a third) of each base station was being properly loaded. They also emphasised that the trial was only using 20MHz (10MHz in each direction) of spectrum in the 800MHz band, the frequency slab to be auctioned off next year - Ofcom schedules and legal challenges permitting.
20MHz is probably as much 800MHz spectrum bandwidth as any company can expect to win in the auction, there's only 60MHz up for grabs and four players bidding for it, but LTE can expand to consume twice that amount if it did become available.
The Cornish trial will run until the end of January, at which point 180 people will have to return to the disconnected side of the digital divide, somewhat to their alarm. But the knowledge that network sharing is practical could well shape bidding strategies when the mega-auction comes, as well as giving hope to the disconnected in the rest of the UK that the forth generation might be the generation that finally connects them up. ®
* EE's rep actually used the term, showing his age if nothing else.