London's Poor 5G Blamed On Spectrum, Investment, And Timing Of Huawei Ban

Interview Recent research found that London is ranked at the foot of the table when it comes to 5G mobile service, but why should that be? The answer is a combination of issues, including available spectrum, investment and the great Huawei replacement.

That report on 5G networks was produced by MedUX, a mobile testing and monitoring specialist, which listed England's capital as bottom of the heap for quality of service in a survey of 15 major European cities.

Yet London is a major tech and financial hub, and its networks were built using the same equipment as some other metropolises, so why should it appear to do so badly?

For one thing, Britain's networks were not allocated so-called high-frequency millimetre wave (mmWave) bands, which allow for higher data rates but also have limited range due to signal attenuation.

That may change in future, as UK telecoms regulator Ofcom plans to release spectrum in the 25.1-27.5 GHz and 40.5-43.5 GHz bands this year, making them available for operators to deliver faster services. These are set to be restricted to dense urban areas, precisely because they only operate over a range of a few kilometers.

However the problem is that 5G is now perceived by many Brits as not really worth having, Professor Mohamed-Slim Alouini of the King Abdullah University of Science and Technology (KAUST), and an expert in wireless networks, tells The Register. Due to a lack of interest, networks have been unwilling to invest the sums of money that would fix some of the problems, leading to the current situation, he says.

"When 5G was advertised, it was advertised around a few use cases including enhanced high speed connectivity, ultra low latency, high reliability, and massive network capacity. These were kind of the flagship user scenarios of 5G," says Prof Alouini, who is also an IEEE Fellow.

Those features largely depended upon the entire network being upgraded, including the network core in addition to the cell towers, known as the radio access network (RAN).

In the UK, however, the network operators just added 5G radios onto the existing infrastructure built for 4G, which meant users did not really perceive much of a service improvement between 4G and 5G, leading to the impression that it wasn't worth paying extra money for.

This turns into a kind of vicious circle, where funding is needed to improve the service, but customer interest is low precisely because the current service is poor.

"The way to reduce latency is to use the concept of edge transmission or edge caching, which means you come as close as possible to the customers, but to be able to do that you need to have a lot of infrastructure. You need to densify your network," Prof Alouini tells us.

"If you don't have investment, why would you do that? And you end up having patchy services because you didn't put in enough base stations. So it's a loop in my mind that 'you don't invest, you don't get enough customers'," he adds.

There is more. The vendors and researchers quickly realized that mmWave is great for super-dense environments, but again the limited range meant operators would have to deploy a larger number of cell sites in order to cover an entire city. That put the focus on the so-called mid-band spectrum, where existing cell services already operate, in order to deliver most 5G services.

"The problem comes because this band is not available equally in all countries. In some countries like the US, that band was made available early and essentially people could take advantage of that," Prof Alouini says.

In the UK, spectrum for 5G was auctioned off in a somewhat piecemeal process, with the first sale in 2018 of some mid-band frequencies around 3.4GHz, followed by another of frequencies in the 3.6-3.8GHz range in 2020, while that of the low-band 700MHz spectrum was delayed until 2021.

Prof Alouini suspects this may have contributed, with UK operators not able to get enough spectrum when they needed it, and so were unwilling to put in the full investment necessary to build the infrastructure that would deliver on 5G's promises.

This would require networks to be upgraded to 5G Standalone (5G SA), something that is only starting to happen now after the government announced the policy goal of having it in place for all populated areas of the UK by 2030.

Another factor the professor points to is the decision to ban China-based vendor Huawei from UK telecoms networks. This came at a critical juncture when Britain's telcos were supposed to be ramping up investment into rolling out 5G, but instead they had to halt deployment of Huawei, equipment which had a technical lead over other vendors and was less costly.

"In many European countries, including UK, the ban happened in 2020, you know, so the timing was not good, in the sense that maybe there was not enough time to adapt and get replacements from other vendors like Ericsson and Nokia to replace it," he tells The Reg.

The whole reason for the ban was political pressure from Washington during the first Trump administration, which regarded Huawei as a security risk and leaned heavily on Britain and other countries to scrub their networks of all kit made by the company.

The UK government soon caved and outlawed the deployment of new Huawei equipment, and required its removal and total replacement from Britain's telco infrastructure by 2027. A government minister at the time admitted the move had already set back the local rollout of 5G, had cost up to a billion pounds and would lead to further delays.

"If look at what are the best European cities and the worst European cities, you see the best are Stockholm, Lisbon, Porto, and the worst are Brussels and London," Prof Alouini says. "Stockholm is the home of Ericsson, but if you look at Portugal they banned Huawei in 2023," so they were able to deploy their 5G network and have it up and running before the ban came into effect, he claims.

All of this holds lessons for the nascent efforts into developing the next generation 6G network technology, which researchers and network tech vendors are pushing. One section of the industry, however, is not so keen.

"When I went to Mobile World Congress in Barcelona, I found that mobile network operators are not ready to talk about 6G," the professor says. "They feel we are still behind in 5G, so let's kind of clean it up, make sure we get our return on investment and then we can talk about 6G."

To avoid repeating mistakes, spectrum for 6G needs to be identified and freed up early, long before the network operators are ready to start rolling it out, Prof Alouini says, and there needs to be a clear business case for investment.

"I doubt they will do the same kind of planning of let's build 6G on 5G and then move to 6G standalone. I mean the lesson they learned from 5G is they have to be ready, I think, prepared ahead of time."

Identifying the use case for 6G will be a good start, as a recent article published by the Institute of Electrical and Electronics Engineers (IEEE) found that mobile data growth is slowing, and forecast that consumer data rate demand is set to flatten out below 1 Gbps in just a few years.

• UK's biggest mobile operator starts 3G switchoff, hopes it won't catch out April fools
• London is bottom in Europe for 5G, while Europe lags the rest of the world
• Britain dusts off idle spectrum for rail and emergency comms
• FCC throws open 6 GHz band to unlicensed low-power gizmos

While there is much talk about using terahertz frequencies for 6G, this will hit the same problems as mmWave technology already has, in that it will allow very high data rates but only over a short distance. For mass deployment, 6G is likely to use the upper mid-band region, somewhere around 7 or 8 GHz.

"So if I am in a government regulator or a decision maker, I need to be ready," Prof Alouini says. "I should not wait until 2030 to start making auctions. I need to clean up which means can I reallocate this spectrum? Can I clean it up to do an auction ahead of time?"

Perhaps the biggest lesson is not to overpromise and under-deliver, as happened with 5G. And for the UK at least, another question mark hangs over whether the impending merger of Vodafone and Three will lead to a stalemate in the mobile sector, dominated by three large players, or if competition will lead to the kind of investment needed for 6G. ®