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Mind the gap: Why is the London Underground a mobile blackspot?

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Two years ago, amid the anticipation of the 2012 Olympics, there was hope that London would build a wireless network to make Britain the envy of the world. There was even talk of including phone connections on the Underground.

Sadly, it never quite came to pass. The plan for ubiquitous data never got beyond Virgin Media’s Wi-Fi in the Underground. So two years on from the Games of the XXX Olympiad, what has changed?

Despite a less than rapturous reception, Virgin Media has recently extended its free Wi-Fi to six new stations - Golders Green, Southgate, West Kensington, Parsons Green, Kilburn and East Putney – taking the total to 137 out of 270 stations.

Meanwhile, railways running from London to Manchester, Bedford, Brighton etc are to get upgraded Wi-Fi by 2018, mainly funded by a £70m punctuality fine. Download speeds will be 10 times faster.

No reception

But there’s still no mobile reception in the Underground.

We have the capability. Vodafone, O2 and EE built a network for the English side of the channel tunnel in May 2014. The French half went live nearly two years earlier. It took 10 months to build and no trains were disrupted – this would suggest the problem is political.

At first glance the answer is obvious: you cannot build cell towers in the Tube and placing repeater stations in the tunnel ceilings is costly.

‘Because the tunnels are so small, the trains just about fit. There’s only a half foot gap if you stuck a box there the train would be hit,’ says Dan O’Gorman, a Geek Squad agent at Carphone Warehouse. ‘If one broke you’d have to stop the entire train line.

‘If the Government has their way there’ll be a 24 hour Tube service for central London, even now there’s only a three hour gap for masses of people cleaning the tracks... Repeater stations will lose the signal with each relay the further away they are from the source.’

But if this is the case, why do so many of the world’s metros – Seoul, Berlin, Shanghai, Tokyo – already have full mobile coverage?

Seoul is capital of the country with the world’s fastest, cheapest internet so no surprise there.

Lindsay McComb, content specialist at Q Digital Studio, says: ‘Even while underground (and moving), 4G connections are clear and consistent.

‘In the Seoul subway there are wireless broadband or WiBro [known as WiMAX in the US], antennas spread out at 300-400m intervals in the tunnels and stations. And it’s not just your run-of-the-mill data coverage, the connection is good enough to watch high-def YouTube videos without buffering and I can download at speeds above four megabits per second,’ McComb says.

‘Most major Korean subway stations offer cellphone charging services. Simply head over to the information desk or look for “digital stations”. Free of charge. Though I’ve heard that sometimes they ask you for a quick thank you note!’

That experience was two years ago.

Wi-Fi signals

Of course, the Tube does have some connectivity.

Since June 2012, Virgin Media has provided Wi-Fi in the ticket halls, escalators and platforms of 137 stations.

At first glance this is a great benefit. Emma Hutchinson, senior PR manager at Virgin Media, says: ‘If you want to send an email you can write it while going through the tunnels and send it in the stations… The feedback from people has been very positive, we are planning to roll it out to more stations in the future.’

So why is this not enough? The service has several limitations.

Firstly, it stopped being free in January 2013 though one cannot begrudge Virgin Media for wanting to recoup the cost.

Secondly, around 30% of Britons still have no Wi-Fi enabled device.

Thirdly, the Three network plus most MVNOs have not partnered with Virgin meaning their customers (5% of Londoners) have to buy a Wi-Fi pass costing £2 a day, £5 a week or £15 for two months. This is a lot given that Three offers unlimited data for £12.90 a month.

Three says: ‘We want to make sure our London Underground Wi-Fi proposition offers customers the best experience before rolling it out.’

But the biggest limitation is there is no Wi-Fi in the tunnels.

O’Gorman points out that: ‘Everyone who comes into the store [Carphone Warehouse] is under the impression you can get Wi-Fi anywhere Underground, whereas, of course, the truth is you can only get it on the platform, not on the train or tunnels.’

People rarely spend more than five minutes moving from the ticket hall to the train. Passengers are often in a hurry, there are plenty of free newspapers and the trains rarely stop more than a minute at a time.

Admittedly the Wi-Fi lasts about 10 seconds into the tunnels but it takes just as long to return when trains arrive at the stations.

In addition, much of the limited time is taken up logging in.

By the time a commuter has turned the Wi-Fi on, entered the login page, clicked on the network’s icon, entered their number, password, and clicked “Sign In”, their train has probably arrived.

Also, they will not be the only one using it. O’Gorman explains: ‘People forget the stated speed is up to a certain figure – it depends on the traffic. If you’ve got 5,000 people in one station trying to access the same Wi-Fi, it’s going to be horrifically slow. 3G is OK but it will get worse over the coming years because apparently the networks are going to be removing 3G masts, replacing them with 4G.’

By contrast, there is 4G available on the DLR between Canning Town and Woolwich Arsenal which commuters have already paid for and doesn’t need a login page.

Most generous of all is The Cloud. It provides more than 11,000 hotspots including most Overground stations. It provides an hour of Wi-Fi a day, is paid for by easily ignored adverts and is fast enough to download three hours of video. There is a login page but you only have to click four buttons, and are usually online in 15 seconds.

To be fair, these are above ground so are far easier to build and The Cloud does not work between stations either. The difference is that you have longer waiting times, so more time to use the service.

The cost of building a network for the London Underground is estimated at £100m. Telecoms equipment maker Huawei was willing to pay half of this in February 2011. Huawei claimed it was a gift from one Olympic nation to another and that it could profit by providing ongoing repairs.

A week later the bid was rejected.

Their main opponent was Patrick Mercer, former MP for Newark. He says: ‘I wonder when the eyes of the world are upon us, whether there is sense in using a Chinese firm to install a sensitive mobile network... In the event of a terrorist attack, putting a mobile network on the Underground would be extremely helpful, but it absolutely answers a terrorist’s prayers – to be able to detonate devices on the Underground.’

Mercer had already been expelled from the shadow front bench for racism and would later resign from his seat in April 2014 for breaking lobbying rules.
Huawei was investigated by the US Government in October 2012, although no evidence was found that they had spied for anyone.

Huawei spokesman, Ed Brewster says: ‘TfL [Transport for London] confirmed in 2011 that security was not a factor in the decision not to progress with a mobile network for the Tube, to state otherwise is inaccurate.’

He believes the reason was TfL and Thales (infrastructure provider to the Tube) could not agree terms.


Professor Simon Saunders, director of technology at Real Wireless, believes companies are having to deal with rising expectations: ‘It’s a huge step forward, for an environment which had no wireless to offer passengers previously and has demonstrated that there is a demand. The fact that everyone wants more is a high-quality problem!’

Saunders explains why the UK is behind some countries: ‘Most underground railways worldwide have some provision for wireless services along the track. The fact that London has not yet reached this point is linked to its status as the world’s oldest underground railway, with all the associated space, safety and legacy challenges that come with that.

‘It’s certainly not easy: many miles of track in tunnels, limited space, special safety requirements and a need to build infrastructure which will last for many years and serve the needs of many operators together.’

This argument was countered last year by MP Gareth Bacon, author of the report Calling All Stations. He pointed out that only two lines date back to 1863. Some Paris routes with signal are older than many London lines without signal.

Also, only 45% of the Tube is in tunnels, the majority is above ground or stations.

Virgin Media’s Wi-Fi is fine for writing emails, not for much else. For streaming, you still need to be above ground.

Could this change? Saunders is positive: ‘There are new distributed and small cell radio infrastructures which make this a sensible time to consider this challenging project again.’

We shall see.

Désiré has been musing and writing about technology during a career spanning four decades. He dabbled in website builders and web hosting when DHTML and frames were in vogue and started narrating about the impact of technology on society just before the start of the Y2K hysteria at the turn of the last millennium.