How Whitespace and LTE could solve the UK’s broadband woes

A number of announcements have been made this month which could be very important for the future of wireless services, and specifically for broadband, in the UK.

BT and UK Broadband made announcements covering (literally) opposite ends of the spectrum, with BT extending its whitespace trial and UK Broadband (who currently offer WiMAX wireless broadband services) announcing that it will offer LTE (Long Term Evolution or 4G) services and wholesale LTE services to existing mobile operators. This week, Microsoft launched a whitespace trial starting in Cambridge with BT, BSkyB and the BBC.

Whitespace technology will allow rural communities to get wireless broadband where there’s no real chance of getting any kind of wired service. LTE, meanwhile, is on every mobile network operator’s (MNO) roadmap, it offers faster broadband speeds than current 3G, however the networks can hardly cope with current 3G traffic levels on the limited spectrum they have today, so they’re all counting on the new spectrum that communications regulator Ofcom is meant to be auctioning next year. UK Broadband’s offering may offer the MNOs a quick fix to locally increase capacity in urban “hot zones”.

Crowded airwaves

Radio spectrum is a valuable commodity and in the UK most of it has already been allocated (noting the exceptions which Ofcom will hopefully auction off soon). It’s a crowded space with much of the spectrum being allocated to the government’s Ministry of Defence, and other sections going to commercial TV and radio, mobile communications and even some space reserved for public use such the 2.4GHz band which anyone can use for services such as WiFi or Bluetooth.

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The radio spectrum is allocated by Ofcom, and all of the UK spectrum is covered by licenses, some of these (like TV broadcast licenses or the 3G licenses) have generated billions of pounds of revenue for the UK government. Even spectrum like the 2.4GHz band (which is free to use) is covered by a license, but Ofcom publishes a generic agreement that all vendors manufacturing systems must adhere too. Even mobile phone handsets require a license, it’s just that they’re covered by the mobile network.

As an aside, the UK has one of the most punitive regulatory environments when it comes to radio, which stems from when it was invented. It was much easier to prosecute a spy for having a radio transmitter or receiver which wasn’t licensed than to actually prove they were spying.

Ofcom planned to auction the 800MHz and 2.6GHz bands in 2007, unfortunately they’ve been plagued with legal battles so the auctions keep getting delayed. Both bands are valuable as 800MHz is good for wireless broadband and can cover large distances while 2.6GHz can carry a lot of data but is only useful for short-range cells, the big advantage is that they’re both GSM/3G bands so mobile phones and dongles can use them directly.

Though legal wrangles may still delay the auctions significantly, Ofcom announced earlier this year that it will allow spectrum trading so the networks can sell off all or parts of their allocations to other operators which might head off some of the legal complaints.

What is ‘Whitespace’?

BT’s whitespace trial is interesting as this technology looks for gaps in existing spectrum and uses those gaps to send information through. In the past, transmitters and receivers weren’t particularly accurate (think big glowing valves) and bands were generally broken down into channels – there would be deliberate gaps left between channels so the channels didn’t ‘bleed’ over into each other. Now modern equipment is much more accurate so a lot of these ‘guard’ bands are sitting there doing nothing, no longer needed.

There is also lots of spectrum that isn’t used in particular areas dues to specific frequency planning issues. If a transmitter and receiver know what’s being used around them, they can fill in the gaps and use that spectrum without interfering with anything else. It’s these areas of unused spectrum that’s known as ‘whitespace’.

BT’s trial uses spectrum between 400 and 800MHz and is taking place on the Isle of Bute (off Scotland). Whitespace isn’t much use in congested areas like big cities, because there are just too many things going on, but for remote areas (where wired broadband is never likely to be rolled-out to due to the poor economics or just environmental conditions) it’s a perfect solution. The signals are sub 1GHz therefore propagate well and interference is likely to be minimal so BT can roll-out wireless broadband to remote areas (covering a large area with minimal infrastructure).

The trials running in Cambridge will also use the same technology and has some big players that can make a difference and produce consumer equipment. Sky already runs a broadband network and it could use whitespace to offer wireless services.

LTE

At the other end of the spectrum, UK Broadband (a subsidiary of Hong Kong based PPCW) have a national set of licenses in the 3.5/3.6GHz bands (they acquired Pipex Wireless last year so there is no competition in these bands). Originally, both UK Broadband and Pipex were offering WiMAX wireless broadband services, but neither managed any substantial roll-outs or gained a large customer base.

Now UK Broadband has said it will offer LTE (Long-term Evolution) services and offer a wholesale service to existing 3G operators and MVNOs (‘virtual operators’) such as Virgin Media. The MVNOs tend to suffer, especially for data services, as their mobile services are piggy-backed onto an existing operator such as 3UK or EverythingEverywhere. Thus any capacity problems the operator has, the MVNO is likely to be affected by further.

Though 3.5/3.6GHz cells wont cover large areas they are good for localised infrastructure and each cell can provide high bandwidth/capacities for data which means they’re perfect for adding capacity to existing networks. Though 2.6GHz would also be good for this, the 3.5/3.6GHz bands are available now and UK Broadband say they can roll-out an LTE network by 2012 thus negating any worries about auction delays.

There’s still a catch, as LTE services don’t generally operate at 3.5/3.6GHz so UK Broadband will need to get a vendor to specifically manufacture cells and consumer equipment. So your phone is unlikely to work on this new LTE network, but a dongle could easily be developed that can use the normal LTE bands (ie. 2G and 3G) and the new UK Broadband ones, thus off-loading high-capacity data requirements in cities and other areas from the existing 3G cells which will make the networks better for everyone.

So, between BT (and partners) and UK Broadband the solution to remote broadband and localised high-capacity data cells might be found.