Spectrum chaos in South Africa
Telkom says that while trying to use emergency network capacity handed out at the start of the Covid-19 pandemic, it ran into significant problems.
MyBroadband spoke to Telkom’s head of network planning and engineering Lebo Masalesa, who explained that “digital dividend” frequencies they were told they could use, they found occupied.
Masalesa said there is a disconnect between which frequencies government says is available, what industry regulator Icasa says is available, and their experience on the ground.
Telkom has first-hand experience thanks to the Independent Communications Authority of South Africa (Icasa) releasing temporary emergency-use radio frequency spectrum to mobile networks in April 2020.
This was to help operators rapidly expand their networks to deal with the expected surge in demand for Internet access as South Africans were told to work from home.
Radio frequency spectrum is the raw network capacity used to connect mobile devices to cellular towers.
By all accounts, Icasa’s move worked.
Prices came down, and research from MyBroadband Insights showed a constant improvement in mobile network quality throughout the pandemic, despite a massive increase in data consumption.
The regulator did try to take away the temporary spectrum at various points in the pandemic but was met with backlash and even legal challenges.
Ultimately everyone settled on having a re-application process, which allowed Icasa to reassign a portion of lower-frequency spectrum to Rain and assign some spectrum to Cell C, which missed out in the first round.
Throughout this, Icasa was trying to assign this additional radio frequency spectrum on a more permanent basis.
In-line with international best practice, it aims to use an auction to help decide which operator should receive some of the more hotly-contested frequency bands.
However, Telkom, E-tv, and MTN met Icasa’s 2020/21 attempt with legal challenges.
Icasa eventually conceded defeat and issued a fresh invitation to apply document, to which Telkom promptly responded with another High Court application.
Among Telkom’s concerns was that lower-frequency spectrum, known as the sub-1GHz or “digital dividend” bands, were still occupied.
Obtaining sub-1GHz spectrum is extremely important to Telkom as it does not currently have any, while its competitors do.
Telkom has asked the court to order Icasa to implement remedies that compensate for the event that operators could not use some of the digital dividend spectrum after the auction.
It was initially understood that Telkom’s concerns were mainly over the fact that E-tv owner eMedia is refusing to relinquish its sub-1GHz spectrum by the time Icasa hopes to conclude the auction.
However, based on the information Masalesa provided, the issue is much more severe than broadcasters still occupying frequencies used for old analogue TV transmissions.
Telkom map of interference in sub-1GHz “digital dividend” frequency bands. Coloured areas represent auction batches. Pins represent sites where Telkom detected interference.
In one example, Masalesa said Telkom tried to roll out extra network capacity in Bloemfontein, where they were informed the frequencies Icasa assigned to them were free.
However, when they switched their sites on, they found significant interference with their signal.
In some instances, Telkom even had state-owned signal distributor Sentech or Icasa phoning them to switch off its sites because they had received complaints of interference.
Masalesa explained that investing a lot of money into a site only to be told they can’t use it is a terrible situation for an operator.
It was also not only Telkom’s sub-1GHz spectrum affected by this issue.
Masalesa said that, in several instances, they had detected interference in frequency bands assigned to other operators.
The map above shows the three batches in which Icasa wants to release the digital dividend spectrum. Each batch is a coloured area.
Pins represent sites where Telkom detected interference. These problems occur in every batch of spectrum.
Undocumented “self-help” TV signal repeater towers
One source of the problem is that many South Africans with poor TV reception had erected their own repeater sites.
While many of these “self-help” sites are Sentech-approved, many are unaccounted for — they do not appear in any of the documentation the signal distributor or Icasa provided to Telkom.
“We suspect it could be a case that Sentech does not have a view of all the repeaters out there and are unsure if these repeaters are deployed with their permission,” Masalesa told MyBroadband.
Masalesa said that while they found the issue was more pronounced in the 700MHz band, it also happened in 800MHz frequencies.
“[The problem] is spread across the different bands,” he said.
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