Cellular repeaters: Can you hear me now?
Pass go, do not go to jail
Operating or installing an unlicensed radio transmitter can get you a year in chokey, or six months if you're lucky enough to be in Scotland, and El Reg would never condone such activity - so please enjoy the following work of speculative fiction.
A cellular repeater is a base station, but one whose only connection to the rest of the cellular network is over that network. They are normally installed, by network operators, in places with weak coverage where a yagi antenna pointed in the right direction can pick up a good signal; that connection is then used to provide connectivity to nearby handsets using a microcell base station. But these days cellular repeaters aren't just being deployed by network operators, despite the legal ambiguity within which they exist.
Cell Antenna, the company so effectively pushing to fit jammers in prisons on both sides of the pond, will happily sell you a cellular repeater in the UK. The company has been supplying them to US punters for years, where they are legal, but on this side of the pond Ofcom's guidelines leave little apparent room for doubt:
Installation or use of repeater devices by anyone without a licence is a criminal offence under Section 35 of the WT Act 2006. Any person found guilty of installing or using such devices without a licence would be liable on conviction to a fine of up to £5000 and/or up to 51 weeks’ imprisonment (Six months in Scotland and Northern Ireland).
...but we'll come back to that later. Initially, let's imagine you are one of the 45 per cent of home workers, or 30 per cent of office workers, whose mobile coverage is limited to near windows or the far left corner of the car park - then a cellular repeater would be just what you need, if they were legal. A basic repeater will set you back just short of £400, and you can't expect any operator subsidy on that.
The kit comes in an array of boxes - ours lacked instructions of any kind, but even without them connecting the bits together isn't complicated. The yagi looks a small TV aerial and is supposed to be pointed at the nearest base station (Google Maps can help here), though we didn't find that necessary: it is happier outside, though, and comes with a decent length of cable for fitting. That connects to a mains-powered booster, about the size of a couple of cigarette packets taped together, which in turn connects to a microcell antenna about the size of a hardback book.
The microcell is designed for wall mounting, and covered in the kind of white plastic that would render it instantly invisible in just about any office environment. Cellular repeaters are frequency-based: so generally only work with a single network operator - ours was configured for use with Vodafone.
Once plugged in the only indication that anything is happening is a green light on the booster, alongside a second light labelled "alarm" that only comes on when things aren't working. Within seconds of being switched on every Vodafone handset in the area reported a full-strength signal, and were able to make and receive calls without difficulty - even from locations that had previously been completely lacking in coverage.
Switching off the power resulted in the signal disappearing, though oddly calls that were already in progress were maintained as the handset was able to switch to a previously-unseen base station for continuing an already-established connection.
Given the utility of the repeater it's a shame you're not legally allowed to use one, though Cell Antenna maintain that if anyone at your network operator tells you it's OK; even the prole on the helpdesk, then you are legally fine as the licence holder has given you permission. We contacted all the network operators, as well as Ofcom, to seek an opinion.
3 said it had never really given the matter much thought, while T-Mobile said it planned to make such technology redundant by offering its customers Femtocells instead. The rest said they would look into it and let us know - so perhaps they're still forming opinions.
What we do know is that no one has ever been arrested, or charged, for using or installing a cellular repeater, and until the boys in blue come knocking at Vulture Towers we'll be able to hear you fine. ®
May I direct you to the Internet Engineering Task Force's RFC1149 ?
Link at http://tools.ietf.org/html/rfc1149
Data rate a bit slow, but might solve a 'lofty' problem.
When I worked at Nokia, we had to do seriously stringent tests on the (GSM) basestations I was involved in designing. European (ETSI) regulations were more stringent than American (ANSI) standards, but I spent many night hours and weekends in an accoustic/EMC measuring room, getting the kit's unwanted - out-of-band- radiation down to acceptable limits. I wanted to acheive ETSI, even tho' the kit was for the Americas' markets
GSM 11.05, 11.21 and 07.01 standards spring to mind, but now it's all under the 3G Partnership Programme - (3gpp)
So, I can't see how a couple of screwed-together fag-packet-sized tin boxes probably made in Taiwan can come close to the requirements.
Bugger me, the standards were strict!
Mobile Provider Approval
Approval from your mobile operator would almost certainly make it legal. You mobile operator holds a licence for that particular frequency, if they were to approve your use of a repeater then you would be covered by their licence.
However, there is a possibility that the use of a repeater could cause interference. It might be a pile of cheap sh*t that causes interference outside it's stated frequency. Even if it is a quality device that operates as it should, it would be hard to tell what effects it may have on the surrounding area without a full survey. Imagine your home is in a dead spot, but homes a short distance away are not. Installing a repeater in your home could potentially cause problems with their reception. Would the solution be for them to install a repeater too? So you can see why mobile operators may be cagey about people installing repeaters without proper planning.
When we were looking into a contract with a new mobile provider we stated that we were concerned that coverage may be poor in some of our buildings. Some of the bidding operators stated that they would install repeaters at no extra charge in any building where we had problems. So the mobile companies have no problems with repeaters, as long as they are the right repeaters and they know about them and their effects.