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Radio frequencies and pro audio: an exclusive interview with Ofcom

UK spectrum and broadcast regulator Ofcom has been at the forefront of reallocating spectrum for new mobile and media uses. This has brought it into conflict with wireless microphone users, who feel it is not always open about its approach and attitudes. In a rare – but not straightforward – interview, Kevin Hilton tries to get a clearer picture…

Radio frequency spectrum is a subject that I’ve written a lot about. Initially it was largely a technical issue, looking at how broadcasters and PMSE (programme makers and special events) users could get the necessary number of frequencies for a job without interference from other devices.

The clearance of 800MHz made it both a political and a business story, as hire companies, installers, sound designers and broadcast engineers faced changing their stocks of wireless microphones and moving to new frequencies. In the UK this process began in 2006 with the Digital Dividend, overseen by Ofcom, which administers spectrum, as well as regulating broadcasting and telecoms.

Ofcom has been a prime mover in preparations for a digital, interconnected future in the UK based on new wireless and mobile technologies. The Digital Dividend was predicated on switching off analogue television channels and the transition to digital terrestrial TV (DTT). While 256MHz of the 800MHz band was allocated for DTT, over 50% of it was put up for auction, with telecom operators seen as having the necessary spending power to secure frequencies for mobile data services.

PMSE had made good use of the 800MHz band, with both interlaced space between TV channels and the widely available channel 69. Moving to other frequencies caused users to buy new equipment and, although compensation was made available by the UK government, many in the business thought it was inadequate. Just as the situation seemed to be stabilising, the 2012 World Radio Conference (WRC) proposed that the 700MHz band should be made available for mobile network operators.

WRC-15 ratified the move, although many observers saw it as merely rubberstamping. Ofcom was an early proponent of designating 700MHz for mobile use and last year announced it was accelerating the process, aiming to make frequencies available for mobile data operators by the second quarter of 2020, 18 months earlier than originally proposed.

The PMSE sector, including users, hire companies, manufacturers and lobby groups, made their frustration and displeasure known. Alan March, senior manager for spectrum affairs at Sennheiser and a key spokesman with BEIRG (British Entertainment Industry Radio Group), pointed out that wireless mic/IEM operators would lose 96MHz, with Ofcom’s proposed replacement set of frequencies – 960-1164MHz – not providing “full mitigation” for the loss of 700MHz. “Manufacturers are developing new equipment, but the real problems could be in the mid to long term,” he told me last year.

These new developments have kept the issue alive and I have continued to write stories about it. The most recent, prior to this feature, was for theatre industry newspaper The Stage. The brief was to explain spectrum and the ramifications of the 700MHz band clearance to a non-technical readership. I outlined the background and included comments from various interested parties, including Alan March, theatre sound design-rental company Autograph Sound Recording and Terry Tew Light and Sound, which provides large amounts of wireless mics for top rated entertainment programmes such as the BBC’s Strictly Come Dancing.

The Ofcom press office provided some comment but, as has often been the case, no input from any executives or members of the spectrum policy-making team other than general statements. The piece was well received but most unexpected of all was a call from my contact in the Ofcom communications department, resulting in the offer of an interview with one of its executives. The arrangements shifted from a phone or face-to-face conversation to email questions and back again. My position was that spectrum is an important area for the pro audio sector, which remains concerned and, in some instances, unhappy about Ofcom’s handling of the various reallocations. Eventually, our questions were put to principal spectrum policy manager Vaughan John, whose written responses form the basis of the rest of this feature, with my questions and background, plus comments from industry figures.

One aim of the interview was to clarify Ofcom’s policy on making more frequencies available for telecom and mobile service providers. The PMSE community believes the regulator has a preference for emerging wireless technologies, notably White Space Devices (WSD) and the Internet of Things (IoT), as well as the ever expanding smartphone market, which is preparing for 5G and LTE (long term evolution).

“Mobile data services are already very important to people and businesses who rely increasingly on devices like smartphones and tablets,” John explains. “The IoT is another major growth area. For all these reasons, demand for mobile data is growing rapidly and we expect it to keep growing. We have a duty to secure the optimal use of spectrum. Where the market can’t deliver that, we can take action. We already have work in place to make more spectrum available for mobile data services over the coming years. We’re preparing to award the 2.3GHz and 3.4GHz bands and have decided to bring forward the release of the 700MHz band. In 2015 we enabled access to UHF white spaces, which can be used for mobile data.”

Demand for mobile data is growing rapidly and we expect it to keep growing. We have a duty to secure the optimal use of spectrum

Vaughan John

While the perception is that Ofcom is making frequencies available for telecom and new media operators as they want – and can pay – for them, John does strike a pragmatic note: “There may be limited benefit in making more spectrum available for mobile data services if we cannot meet the demand at lower cost, through technology or network improvements. But where we need to change the use of spectrum, this can take years to prepare. For example, we need to secure necessary international agreements. A key part of preparing is to ensure we take account of the interests of all spectrum users, including assessing and mitigating any harmful interference risks.”

Further interference has been a major concern ever since the concept of WSDs was announced. Because WSDs operate in the interleaved areas between TV channels and have the capability to scan for suitable frequencies, broadcasters have been worried these transmissions could break into broadcast signals. PMSE users have similar concerns, particularly as many WSDs are likely to be consumer devices and could pop up anywhere at any time. “No one can guarantee that any system will be free of interference, but we work hard to ensure any risks are low,” says John. “For white space and mobile devices we worked to carefully test and analyse these systems, to derive levels that ensure a low probability of harmful interference to digital TV and PMSE users. We published and consulted on the analysis and took on board stakeholder comments before concluding on the coexistence arrangements.”

Among the procedures proposed by Ofcom to ensure as much as possible that users had clear access to specific frequencies at a given time was a database of new media devices. John comments that Ofcom still regards dynamic spectrum access as an effective option for making spectrum available: “The TV white space framework has been in operation since the end of 2015, when the relevant regulations came into force. There are now seven qualified databases, with two providing operational services. Take-up has been gradual but there are some operational deployments and interest is definitely growing.”

Although PMSE was mentioned in the Digital Dividend consultation document, there had to be considerable lobbying by pro audio groups, including BEIRG, before Ofcom recognised it as an area for special consideration. Even with this, the reality remained that those using wireless mics and IEMs constitute a relatively small grouping and certainly do not have the financial clout of telecom and new tech companies when it comes to bidding for spectrum.

The irony is that PMSE is involved in productions that generate a substantial income for the UK, with major broadcast productions, both of scheduled TV programmes and OBs of live events (a good recent example being the One Love Manchester concert), big West End theatre shows and tours by some of the biggest bands around. All are demanding more and more radio mics and in-ear monitoring, which in turn calls for many channels of wireless.

“We absolutely agree that the PMSE sector is an important user of spectrum,” John says. “We have committed significant effort and resources to ensure that, as we release the 700MHz band, we safeguard the important benefits that PMSE services deliver to people and businesses. To take just one example, the concerts and performances that rely on audio PMSE devices make a really important contribution to the UK’s creative economy and cultural life. We want to ensure PMSE users can access the spectrum they need to keep staging these events, without compromising their production values, so we have made additional spectrum available in the 960MHz band. We believe this extra spectrum, plus the remaining spectrum shared with digital TV, coupled with improvements in technology, will allow the PMSE sector to thrive.”

Despite this, many in the PMSE community feel Ofcom continues to underestimate what is involved in major live and broadcast productions and how many frequencies are needed. A contact of mine who has attended spectrum policy meetings at Ofcom says during recent discussions Ofcom said 93% of PMSE users needed only three TV channels. My sources say many productions, which are not one-offs but TV series or long-running musicals, need more than that. For example, Britain’s Got Talent, which runs for several weeks, uses 130 channels of RF. While Ofcom predicts only 10 to 20 events a year will be affected, the PMSE lobby thinks it will more like 100.

John stands by Ofcom’s figures, although does not disclose how they were reached. “We don’t accept that view,” he says of the PMSE point. “Our work in 2014 showed that the vast majority (93%) of PMSE use required fewer than 24 audio channels, which we believe can be met with 24MHz of spectrum – in other words, three 8MHz TV broadcast channels. The remaining 7%, including some high-profile events, could be affected by changes in the 700MHz band. We found this accounted for around 1,000 events per year, across various sectors such as concerts, musical theatre and broadcasting. When we looked at the spectrum needs of those events, we found that only the top 10 to 20, in terms of spectrum demand, would potentially have a shortfall in supply. We absolutely recognise that could affect production quality, which is why we have provided additional spectrum for PMSE use.”

The concerts and performances that rely on audio PMSE devices make a really important contribution to the UK’s creative economy and cultural life

Vaughan John

Additional spectrum for PMSE to bolster the white space capacity available to it will be provided in the 960-1164MHz range. Commonly known as the Air Band, this is currently used solely for DME (distance measuring equipment) transponders on commercial aircraft in UK airspace. The issue of interference is raised again by this decision, with the added concern of liability if any accidents were caused by wireless mics operating in proximity to aircraft. “We decided,” says John, “with the agreement of the Civil Aviation Authority (CAA), to allow low power audio PMSE users access to the frequency band 960-1164MHz, which is shared with existing aeronautical systems. We worked with the CAA to ensure that sharing in this band does not compromise the safe operation of aeronautical systems.”

Existing wireless mic systems do not work in the Air Band, so users will either have to buy emerging digital radio mics or technology designed specifically for DME operation. Shure has produced prototype systems and carried out tests, which Tuomo George-Tolonen, manager of the pro audio group at Shure Distribution, described as “positive from an operational standpoint”. A business stumbling block is that the Air Band is purely an UK solution to restricted spectrum for PMSE, so manufacturers may not see products for this application as commercially viable.

Either way wireless mic users will be forced to buy new stock. As with the move from 800MHz, the UK Government is making funds available for compensation, although the market anticipates it will not fully cover the cost of replacement. Terry Tew refers to the 2014 report by former EU Commissioner Pascal Lamy, which stated efforts should be made so that “PMSE users are left no worse or no better off than they would have been without any clearance of 700MHz”.

John points out that the Lamy Report recommended: “The timely identification and harmonisation of additional spectrum (tuning ranges) for PMSE is required as a substitute capacity… The broadcasting and PMSE sectors should not be disadvantaged by such a transition and cost compensation should be duly addressed.” John adds that Ofcom has “broadly addressed” the first of those recommendations by making the 960Mhz band available. As for compensation, John comments: “The government has decided to fund a grant scheme to support PMSE equipment owners that need to vacate the 700MHz band. Our job is to design and run the scheme to disburse the funds. We have just consulted publicly on how that will work and expect to outline our decisions later this year.”

Broadcast transmission and reception will be less affected by the move from 700MHz than with the 800MHz clearance, although some households may have to install new aerials. Even so, there are indications that telecom and streaming service providers would prefer TV delivery to move to new technologies, such as LTE, with DTT frequencies freed up for the purpose. Broadcasters including the BBC have calculated the cost of transmitting in this way would be prohibitive for both TV channels and viewers.

John comments that Ofcom is “always monitoring developments in mobile broadcast technology” and can see the possibility of mobile and traditional broadcast technologies converging in the long term. “But there is a debate about whether mobile broadcast technologies are as efficient as the latest traditional broadcast technologies when you compare networks of similar complexity and coverage,” he says. “I’m thinking of technologies such as DVB-T2, MPEG-4 and HEVC. Also, around three-quarters of homes in the UK receive their TV using equipment based on traditional broadcast technologies. So there would be a very significant challenge migrating to mobile broadcast technology in the short to medium term.”

While Vaughan John and Ofcom answered our questions as comprehensively as is possible given the format, the crucial point of whether there would be any further moves or changes for PMSE and DTT in terms of spectrum went unacknowledged.

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