Tag Archives: mobile

What you need to know about 5G coverage

I once went to a talk by Ben Goldacre, in which he said he was going to get a T-shirt printed. This was because he seemed to be giving the same response to lots of questions recently, and it would be easier if people could just read the answer as they walked up to him. The text would say, “I think you’ll find it’s a bit more complicated than that.”

It was a throwaway comment, but I often think of it, most recently as the British mobile phone networks start rolling out 5G and (because they spent so much on licensing the spectrum) are being very energetic about telling us how wonderful it is.

Yes, 5G can be faster. Potentially much faster. That’s the main marketing push, of course: you can play games more interactively and watch higher-quality videos more quickly. Marketing people like simple numbers. Which is fine, but it’s just an incremental change to 4G, and many people, including me, find it hard to get very excited about that.

I’m far from being an expert on mobile networks, but I have some friends who are, and I’m slowly learning that there are lots of other aspects to consider. Here are a few lesser-known facts about 5G:

  • First, it makes it easier to add large numbers of devices to the network, for Internet-of-things-type applications. If you’re a farmer deploying thousands of soil-humidity sensors across your fields, for example, or a council putting environment-monitoring sensors on every lamppost, 4G wouldn’t be a very viable way to do it. 5G might be, though whether it will really be an affordable one remains to be seen. It probably won’t compete with technologies like LoRaWAN and SigFox for these low-bandwidth applications, where you often want battery-powered devices with a battery life measured in years. But no doubt it will find a niche in due course.
  • One of the more interesting characteristics, for me, is the potential for much lower-latency connections. When your phone asks, say, a DNS server for the address of ‘statusq.org’, the amount of data actually being transmitted is small, and won’t be affected much by a big increase in bandwidth. What’s important is the round -trip time, and 5G offers the potential for this to be much smaller. (If you just want to send a postcard and get a reply, it doesn’t matter how big the postal service’s van’s are, but it does matter how fast they drive them to the destination and back.) This will affect how natural your video calls feel, because you won’t be talking over each other so much. It may one day affect how quickly your autonomous vehicle knows that a car ahead of you has slammed on its brakes. But in the meantime it will also speed up much more trivial things, like how quickly your email program can check whether you have new email.
  • There are several different bits of radio spectrum – three main ones – that can be used by 5G. This is actually really important, and ordinary users need to be educated about it. Why? Well, as a rough approximation, it’s a basic law that higher-frequency radio signals can transfer more information, but over shorter distances. In the UK, we currently use the middle chunk of 5G spectrum, which is a sensible compromise, but gives you neither the highest speeds, nor the biggest coverage. In some parts of the USA, they are able to use the highest frequencies already, which means you can find YouTube videos of people getting phenomenal data rates, but if you go out and spend a thousand quid on a 5G phone here, you’ll never match them. Not for the next few years, anyway. More importantly, in my opinion, there is a lower-frequency range (below 1Ghz) which will allow transmission over greater distances — which is good for coverage — but at lower speeds. Here’s the important thing: When this becomes available in the UK, it will allow the phone companies truthfully to claim substantial geographic 5G coverage. But it’s also important to note that connections in this spectrum will be slower than 4G. So if you are mostly (like me) in an area that hovers between 3G and 4G, and you hear that – hurrah! – 5G coverage is finally available in your area, you may be very excited and go and spend lots of money on a 5G phone, only to find that things get slower. You have been warned.

So, yes, 5G is generally a good thing, or will be in a couple of years. And it has key advantages other than just streaming Netflix in higher resolution.

But perhaps the best news, if your family and friends start asking you about it, is that Ben did actually go ahead and create those T-shirts.

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Con-Text

The phenomenal success of SMS text messages is a fascinating example of many things – the need for an asynchronous communications mechanism between humans, the surprising adoption of what was originally a test facility for engineers, the merits of enforced brevity in communications, and our voluntary blindness to some costs when they’re expressed in a certain way.

Let me explain that last point. Let’s say that a text message, once outside your allowance, costs you 7p, and that the average text is maybe 70 characters long, so a character costs you 0.1p. On this basis, a megabyte of data costs £1000. About $1600. (A little more, actually, since SMS characters are only 7-bits). Or, to put it another way: to send a floppy disk’s worth of data would probably cost you a lot more than the computer from which you sent it. To send an MP3 track would cost you about the same as a car. And in my case, if I happen to be in the States when I send a text, it costs seven times as much. Seven cars.

Now, you could argue that everybody gets lots of texts in their calling plan, which is of course true, at least in your home country – I never get close to exhausting my allowance – but it’s this theoretical underlying price that allows the networks to charge for this as a bonus. Suppose you pay £3 more per month for a plan that gives you 300 texts instead of 100 texts. It looks like a bargain – you’re getting those texts for just 1.5p each! That’s only £220 or so for a megabyte, or, in music terms, a thousand quid per track.

Now, if you have a smartphone, consider the data portion of your plan. I’m looking at two Vodafone SIM-only schemes here, and the only difference between them is 500MB of data per month. The price difference is £5 – i.e. one penny per megabyte.

This factor of twenty thousand in the two different ways of sending data, over the same network, from the same device, has always amazed me. There are lots of approximations in the above calculations, of course. You could point out that IP-based traffic has lots of overheads, which of course it does, for small amounts of data, but that’s mostly because we often see that data wrapped in a web page. I also assumed that people on average only type 10 words per text; if you always used your full 160 characters you’d save a fair amount per byte. So perhaps the true cost factor is more like 5000, or even 1000. But can you think of any other aspects of your life where choosing that alternative wouldn’t make you pause for thought?

Now, this only exists at all, of course, because in the past there was no choice. Phones were simple devices without a full IP software stack, they had small keyboards and limited ability to create or display any other kind of media. But once you had phones that could run apps like iMessage or WhatsApp, which could efficiently send messages using protocols of their own, the picture changed.

So it’s no surprise that a recent study suggests mobile operators lost $14bn last year because of such apps. It was only a matter of time.

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Having the plastic to go paperless

Micro-SIM adapterKeen though I am to reduce the amount of paper in my life, I am still hesitant about switching all of my utility bills to electronic form because they are often useful, in the UK, as proof of your residential address.

Mobile phone bills, however, tend to be excluded, and since almost every gadget I buy comes with a SIM, I now have quite a few of these! But there’s a different problem when it comes to switching many of these to paperless billing, as illustrated just now by my iPad contract with Vodafone. How do you do it?

Well, you go to Vodafone’s site, and register for an online account. The first thing you need to do is enter your phone number. What is the phone number of my iPhone? Fortunately I had a recent bill handy, so I could look it up, never having needed it for anything other than this before.

Then you hit a second problem. They send you a text message with a security code in it, which you need to enter into the web site. Except, as they well know, this is an iPad, on a special iPad-only contract, and it sadly has no way of reading text messages. (Nor does my Mifi. Nor my 3G dongle, at least with a Mac.) Mmm….

OK, well, SMS messages are sent to the number identified by the SIM, not the device, so I can take the SIM out of the iPad and put it in a phone. (As a matter of course, I always have all my devices unlocked whenever I possibly can, just to make this sort of thing possible.)

Then you hit the third problem. My whopping great iPad has a micro-SIM, while my decidedly smaller iPhone has a regular sized SIM. Fortunately, you can buy adapters which convert one to the other. (If you need to go the other way, you can do so with a pair of scissors, or with a special cutter.)

So the process becomes: move SIM from non-SMS-receiving device to receiving device, having previously unlocked the latter if they’re on different networks, and making use of cutters or adapters as required, then register on first device’s network website, noting and entering any codes that may be texted to you, then restore everything to its previous state afterwards. In the States, where there’s a reasonable chance that your different devices wouldn’t have compatible radio circuitry, it would be even worse.

One feels that this might be a bit of an oversight on the part of the service providers…

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CoverMap

You know those coverage maps that mobile service providers create? The ones that tell you that, yes, there’s blanket 3G coverage in your favourite holiday destination, but when you get there you discover mean ‘slight 3G coverage for people sitting on top of their chimneys facing west under optimal stratospheric conditions’?

Well… it strikes me that, now phones have accessible GPS data, we shouldn’t need to rely on these particular bits of marketing propaganda. Somebody could write a phone app which periodically captures details of the signal and the phone’s location, and uploads them to a service which creates a map showing the true picture. Imagine you could look at your movements over a month or two and discover which operator would really provide you personally with the best service. If you were running the application, the system could even tell you that automatically! (Which would be a good way to get the data-gathering mechanism widely adopted).

Has anyone done this? I might write it up as a student project proposal…

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