At WRC-23, the mobile industry will highlight the coverage benefits of mobile in the UHF band but one recent study suggests demand is increasing in Europe for PMSE spectrum—most of which is in this band. And PMSE users say the use of the 600 MHz band for mobile in the US has created "no-go zones" for outside events.
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In 18 months' time, the use of the UHF band in Region 1 (Europe, the Middle East and Africa) will be reviewed at WRC-23. The lower UHF band, 470—694 MHz, is currently used for digital terrestrial television
(DTT) and programme-making and special events (PMSE) in Europe. Both industries are looking to protect their use of this spectrum.
The loss of the 600 MHz range in the USA is a warning for Europe
In 2017, the European Parliament approved
the relocation of DTT and PMSE from 694—790 MHz and into the lower UHF band to make way for mobile broadband. According to the Wider Spectrum Group, which campaigns on behalf of a broad range of spectrum users, the fate of the UHF bands has been uncertain ever since.
“On the one hand, the decision allowed the mobile sector to harmonise the 700 MHz band
for the mobile service," the group said. "On the other hand, the European audiovisual model is strengthened by the long-term allocation of the sub-700 MHz band to terrestrial broadcasting and PMSE."
Under Decision (EU) 2017/899
, 470—694 MHz is reserved across Europe for DTT and PMSE
until 2030. In preparation for WRC-23, the European Commission ordered a study to be prepared on the future of the bands. Consultants LS telcom and VVA, who are responsible for this study, presented their initial findings on the use of PMSE at a recent workshop on sub-700 MHz spectrum.
The initial results suggested that demand for PMSE is growing in half of the EU member states. 60 per cent of the available spectrum for audio PMSE is in the lower UHF bands.
According to the results of a recent report
by SRF, a Swiss broadcaster, the daily required spectrum for audio PMSE is 110 MHz. “With this amount of spectrum, the requirement of most venues and events can be fulfilled," the report said. "Nevertheless, for major events, the average of the required spectrum is 174 MHz, while the peak demand could be the whole available UHF spectrum of 224 MHz." However, the study also notes that "location, local conditions and events requirements affect the required spectrum significantly".
Anita Debaere, Director at Pearle, an association of employers in the performing arts sector, said that daily use has gone up considerably. “Productions are becoming ever more complex and demanding," she said. "In 2014 there was a daily use of 96 MHz, which since then has been steadily growing every year."
Alternative options for PMSE
Richard Womersley from LS telcom said that some new developments make coexistence with mobile in the lower UHF band possible. “Cognitive PMSE, for example, ensures audio quality in the presence of high amounts of PMSE equipment," he said. "It provides a more automated approach to frequency allocation."
Wireless multichannel audio systems (WMAS) are another development that could benefit PMSE. The technology uses a wider bandwidth—20 MHz—with all users sharing the same channel. It could provide a 50 per cent increase in spectral efficiency, but research regarding standards is still ongoing.
Andreas Wilzeck, head of spectrum policy at equipment maker Sennheiser, said these developments would not change spectrum demand during large events such as the Olympics, football's World Cup and the Eurovision Song Contest. “For big events, we need at least 180 MHz," he said. "This already accounts for current and future developments in audio PMSE technologies, including WMAS.”
There also have been PMSE experiments in the 1700—1800 MHz and 2.4 GHz bands. Jochen Zenthöfer, a spokesperson for the PMSE campaign group SOS, said the bands do not deliver consistent quality. “PMSE needs a contiguous spectrum for physical reasons, especially for large events," he said. "Using alternative spectrum also causes a manufacturing issue. Devices work on the harmonised frequency range designated for PMSE in different countries. If that changes, production will have to follow."
Canada and the USA are among the countries that have already auctioned the 600 MHz band for mobile use. In other regions, countries such as Saudi Arabia and Hong Kong have consulted on doing so. WRC-19 rejected Arab countries' proposal to harmonise the 470—694 MHz band for mobile broadband and decided to consider the future of the whole UHF band at WRC-23.
In the USA, T-Mobile has been building out its network on the 600 MHz band
since the auction in 2017. Audio companies who relied on these frequencies to host large events have to apply for temporary licences. “The technical and radio frequency planning for the Super Bowl begins months in advance and is dependent on available frequency bands," said Wilzeck.
"For this year's Super Bowl, the US regulator granted Sennheiser a special temporary authorization (STA) for the use of 614—673 MHz for the event area in Los Angeles within one kilometre.” The Super Bowl is the biggest game in American football.
“The loss of the 600 MHz range in the USA is a warning for Europe," he said. "Sound engineers already report no-go zones such as outdoor events in Phoenix, Arizona. Existing audio installations are already suffering interference from IMT, even now, in different bands. This causes extra costs for PMSE users to mitigate that interference."
IMT below 1 GHz
In Asia, the APT Wireless Group (AWG) has been looking at a larger, 2 x 40 MHz release of 600 MHz spectrum. India’s recent auction consultation revealed plans to go down to 550 MHz. "The world is now moving towards 600 MHz," said Luciana Camargos, head of spectrum at mobile industry association, the GSMA
. "Low-band spectrum is in short supply and the need for low-band mobile capacity is clear. This spectrum is vital for driving digital inclusion. Driving affordable connectivity throughout all areas—rural, urban and in all markets—will be the benchmark of our success as we look back on the 5G era in a decade’s time."
She added: "In Europe, there is 2 x 95 MHz of paired spectrum below 1 GHz available for mobile, with the option of another 20 MHz of SDL [supplemental downlink]. An extra tranche of 2 x 35 MHz of low-band spectrum in Europe would allow for these areas to get an increase of 30 per cent in download speeds. If Europe were to assign 2 x 40 MHz, this would see the download speed increase by up to 42 per cent in countries that don’t use the SDL tranche."
According to the GSMA, collaboration between stakeholders is key to balancing cross-industry needs. "Solutions to PMSE may vary between regions, and best practice from around the world shows that PMSE can exist after 600 MHz is used by mobile," Camargos said. "Governments are progressing through their digital inclusion agenda with 600 MHz mobile alongside continued PMSE use."•