IoT: Business radio’s worst enemy?
Written by: Sam Fenwick | Published:
IoT device wiping out neighbouring private ambulance system; credit: Maxxwave

April’s Ofcom Business Radio Interest Group meeting discussed many things, including e-licensing, the threat from IoT devices, Ofcom’s licensee survey and LTE in the 450 to 470 MHz band. Sam Fenwick brings you the highlights

Ofcom’s Russell Kent-Smith, director of sector policy, gave an update on the regulator’s new e-licensing system. He explains that it is “part of a wider set of platform changes within Ofcom to give us the modern business systems we need”. Kent-Smith says that the amateur radio licensing system should go live by the end of June, followed by business radio light licensing at some point in July.

“We’d really like to involve the user community and have feedback on the system, so we can make sure that it is as smooth as possible and that the way we provide services reflects your needs. As we get closer to going live the plan is to put more and more information out about the transition.”

He adds that as there are “significant complexities” with integrating technically- assigned licences they won’t be part of the current release, but Ofcom is looking at how to do this.

“You will be able to go online and get light licences instantaneously. Some of the more administrative elements will also be available, such as contact and portfolio management, and specific capabilities for agents to manage their accounts,” he explains.

A new threat to business radio
Maxxwave’s director, Samuel Hunt drew attention to a worrying new issue: interference from RF equipment located in close proximity to business radio infrastructure, such as that from IoT devices, particularly as “it seems to me that [IoT deployment] is definitely happening in UHF. He notes that there are “a lot of people developing IoT wireless protocols like 6LoWPan that make IoT work in narrow bandwidths and we’re about 6-12 months from the start of some trials.” Hunt adds there are several solutions from major household names that are going to be in the licensed 450 MHz band and an IoT project in Leicestershire is transitioning from 868 MHz to a technically-assigned 450 MHz licence.

Hunt shows a slide of Maxxwave’s Leicestershire office with its master mast in close proximity to a lamppost-mounted IoT base station. Both are roughly 240 metres above sea level, compared with Leicester’s 60 metres. “You’re talking about a very high location. Something like that blasting out mobile transmit or simplex frequencies is going to light up a considerable number of co-channel base stations.

“...There’s currently there’s no requirement on a communal site for anybody to install any particular filtering. We’ve complained about this for a long time. Some dealer comes in with a notch-duplexer, puts it on a communal site and raises the noise floor for the whole site, putting several customers off air.

This has traditionally resolved by gentlemen’s agreements. IoT people are tied to cost and they’re not going to be able to put big band- pass filters on their outstations...,” he adds.

Hunt also mentioned an issue with a Maxxwave site in Manchester. “There’s a radio dealer next door who has a mast in close proximity. They only have notch-duplexers on their kit... Every time their kit transmits their notch duplexer is notching out 158 MHz which they receive on and transmitting on 163 MHz. Every time they transmit, the noise floor on 170 MHz, where we have highband base stations receiving, is raised by 20dB. Ofcom has been out there on four occasions and there’s nothing the enforcement people can do.... We’re not giving [the dealer] interference because our site is well engineered and he’s over the moon that we’re losing customers and getting interference...”

“I think the subtlety is not manufacture but installation. We’ve started to lose the concept of installation being part of the licence and I think that is the problem. You can take compliant equipment, you can install it somewhere and it [can] cause interference,” says John Regnault, security consultant at Regnault Inc.

“What I’m advocating and asking for is A) we define what a communal site is, perhaps two transmitters within 250 metres of each other and B) when its a communal site... at the minimum a bandpass filter sufficient to roll off 60dB within a couple of MHz of your transmitter... It should be a requirement before [installation],” says Hunt. “...There are solutions to this problem but as the licensing regime stands today, there are loopholes in it and if we don’t close them now, in 6-12 months’ time when these [IoT] schemes start to deploy, they will make business radio as we know it pretty much unusable...

Hunt asked Clive Corrie, Ofcom’s head of spectrum enforcement for “something proactive that forces them to use correct engineering from day one.”. He goes on to say “our customers just aren’t prepared to be off air for eight weeks whilst you arrange an inspection with us, arrange an inspection with the offending station, issue an enforcement notice, argue about the technicalities then have a six week leadtime on the necessary filter from the manufacturer. After just a few days of having no radio system our customers will start looking elsewhere, radios are that critical to their business”.

“We can’t and this is a European thing,” says Corrie. He explains that while Ofcom is allowed to implement a licensing regime, it can’t place any additional constraints on the free movement and use of radio apparatus over and above that which is written in the RNTT/RED regulations.

“If [apparatus is] causing interference we need evidence to prove that the operation breaches the terms and conditions of a licence or licence-exemption. If it’s a combination of apparatus we may be in a better position,” he says.

Corrie and Tim Cull, head of business radio at the Federation of Communication Services (FCS), agree that the Wireless Telegraphy Act allows Ofcom to make regulations against apparatus that causes harmful interference.

Since the BRIG the FCS has stated it is looking to conduct a detailed technical study of uncontrolled interference from proximate transmitters. It is also seeking to create a specification proposal for CEPT and ETSI to be used to modify existing standards and/or create a new standard.

Ofcom’s licensee survey
As part of the UHF Strategic Review Ofcom carried out a licensee survey, targeted at sectors that use the band for operational reasons. The majority of the more than 900 respondents have technically-assigned licences (73 per cent), with both area defined and simple site licences each accounting for 18 per cent (it was possible to select multiple answers for this question). Sixty-eight per cent said they require exclusive access to spectrum for their radio system. When asked if they use licence-exempt spectrum to meet a business requirement 18 per cent said yes, while 36 per cent said they don’t know.

“You’d be amazed at how many people use the licence-exempt for mission-critical applications,” says Kevin Delaney, spectrum policy and planning manager at Ofcom. “There are various reasons for doing that, such as cost or having a niche piece of equipment. You’re taking the business risk yourself, Ofcom doesn’t mind!”

“The issue to me is that licence-except equipment, particularly Low Power Devices (LPD) and systems in the ISM bands, has no protection from interference,” says Regnault. “Increasingly LPD systems are being used to remotely control large cranes and heavy lifting equipment. If interference were to result in an accident the operators would be completely to blame as they had not taken due care!”

When asked what services they’d be using in five to 10 years’ time, data, GPS, telemetry, remote control and M2M/IoT responses were up, with M2M/IoT jumping from seven per cent of users to 18 per cent. Interestingly, 39 per cent of respondents don’t expect the amount of data they transmit to change in the next five to 10 years.

Only 4.9 per cent said they could see their business switching from radio comms to another technology within the next five to 10 years. Sixteen per cent said they expect the number of channels they use to rise over the same period, compared with just 2.16 per cent predicting a decrease.

“We’re not seeing a huge amount of change in this band,” says Erika Forsberg, senior policy advisor at Ofcom. “There’s still high demand for voice, there’s some increase in data demand. We expect moderate growth in the types of services currently using the band.” She notes that the work has raised questions about future demand for spectrum from utilities, and whether there is scope for increased use of IoT/M2M from both current and new users.

Forsberg adds that Ofcom is seeing some evidence of interference in coastal areas. Throughout 2016 it will monitor sites on the UK’s east coast to measure the levels of interference. It will also monitor conurbations and check the traffic against predicted levels.

The regulator expects “continued high demand in urban areas, primarily London, resulting in a risk of congestion”. Ofcom also notes that it is not clear whether a licence exemption is the most efficient use of the spectrum at 458.5 to 459.5 MHz.

FM54 update
Kuha Sithamparanathan, emergency services spectrum policy manager at Ofcom and FM54 chairman, gave the attendees an update on FM54’s work to produce the harmonised technical conditions and guidance necessary for LTE to be introduced in the 450 MHz to 470 MHz band.

“We’re at a stage where we’re gathering evidence to understand how LTE may affect PMR and other technologies in-band and also adjacent band services,” says Sithamparanathan, adding that the UK’s decision to introduce LTE in this band will depend on Ofcom’s UHF 1 and 2 Strategic Review findings.

“FM54 has put a liaison statement out to Working Group Spectrum Engineering (WGSE) and project team SE7 – which is the specific spectrum engineering group that will be looking at compatibility studies for LTE in this band. They’ve now got the remit to start the work on 450 MHz to 470 MHz,” he explains.

Sithamparanathan adds that more than five countries “are keen on the inclusion of the 410 MHz to 430 MHz part of the band. This is the next stage and we’re going to get SE7 to look at [that] as well.

“I believe the UK on the whole is generally comfortable about this. We can’t put LTE into the 450 MHz to 470 MHz band or the 410 MHz to 430 MHz band until the UHF reviews are concluded. However, we’ve supported the studies because they’re useful to have in our back pocket.”

FCS’ Cull points out: “No matter how big or small the LTE assigned channel actually is, at around 400 MHz there is a strongly-held view that you need guard bands either side.”

“There’s also a view that you can’t put stuff in the guard bands because you [then] mess up the LTE signal itself. So the idea of sharing is probably off the agenda for LTE. Even if you have narrowband IoT you’d still need 2.5 MHz either side of that,” Cull adds.

“There’s a very serious competition issue within narrow frequency ranges if LTE were to be awarded on an exclusive licence basis – and that is that you can’t award a large number of decent licences because you have these colossal guard band requirements.

“In the UK the intended use for some of these things would be very challenging because it’s clear that LTE remains targeted mostly at the data world in a non-mission- critical context. So you have to find places for mission-critical users elsewhere. The basic physics of the situation make LTE extremely difficult in any country where there’s decent use of the band, unless you’re planning to completely empty it and place users in other suitable spectrum. It’s a massive problem.”

I hope this has given you a feel for some of the meeting’s key points. Land Mobile will be following the IoT versus business radio situation with interest as it develops.


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