COMMENT
Written on BA285 whilst flying London to San Francisco. Polished in my Santa Clara hotel and dispatched to silicon.com from an open LAN provided for visitors at a Silicon Valley company.
During the past few weeks I have completed a wi-fi survey of London in order to get some measure of the node density across a 4km-diameter area centred on Liverpool Street Station. As with my prior UK rural survey - see my earlier blog - this didn't involve any special equipment or antennas, only a standard laptop with a software wi-fi sniffer.
Each time I have travelled to London I hired a cab, sat in the back with my laptop and monitored the wi-fi signals as I travelled. As far as is possible in London, I arranged to head north, south, east and west in straight(ish) lines and collected data for a distance of approximately 2km in each direction. In addition, I mapped a few radial and haphazard routes to get a further measure of the true density.
So, what did I find? A sample scan page (with node identifiers and Mac Addresses blanked) is included below for 41 wi-fi nodes of which 14 are open and likely to be accessible for anyone wishing to use them. On this particular 2km run more than 400 nodes in offices, hotels and residences were logged.
Because of the nature of the buildings in London it is impossible to estimate with any precision just how many homes and offices were involved on any route. Suffice to say, on some roads I saw more than 10 different wi-fi signals in as many strides.
What of the results for the entire experiment? Including the transversal routings, the wi-fi density seemed more or less constant with an average of close to 27 per cent of all nodes being open access. I never found a location with open wi-fi density of less than 20 per cent, and never greater than 85 per cent. This high end seemed to be due to the hotels and coffee shops.
So just how do you estimate the total density across the entire area spanning 4km or so? Well, on the basis of no really hard information on road lengths and office/population density, I have assumed a uniform distribution of 200 wi-fi nodes per km along all the major roads moving out from Liverpool Street Station (and radially) for 2km.
According to my map, a very conservative estimate would assume 35 such roads. At a minimum the evidence gathered to date therefore suggests a minimum of 14,000 wi-fi nodes with at least 3,700 operating in an open mode.
So how accurate are my results? Not very! Given the insensitivity of my test equipment - just a laptop - the many high-rise buildings in the area I tested and the labyrinth nature of the roads and alleys, I would guess that a factor of two error is very likely. So the real numbers could be around 30,000 active nodes with around 8,000 open, or even higher.
I rest my case! For all the readers who have emailed me complaining that they cannot see or find wi-fi and have suggested I live in a different world, I think there is now sufficient evidence to say that London and the UK has quite a significant wi-fi density.
Comments
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1. Iain Forsyth
No doubt there are many APs - though sitting at my central london desk I can find one secure one.
However most are secure, and those that are open in cafes and the like are generall charged for and priced at a level that doesn't make them ataractivr to a casual usr like myself.
There is a long way to go before Wi-Fi lives up too its promise / potential
2. John
That's a good point - networks that appear to be 'open' are often expensive services that need payment before getting through the proxy to the real world.
It wouldn't be so bad if a single payment could get wifi access for a week, or even a whole day, at multiple locations, but that rarely pays off (openzone possible, but not widespread enough).
And the results of the survey were based around Liverpool Street, so should only come to the conclusion that wifi access is available in London - not the same for the provinces...
3. Antony Norris
Just driving through not only London, but any built up areas (admittedly South East England) with my PDA set on discover and log on to new networks it would constantly be hitting new networks. What I have noticed over the last couple of years is although there are more wireless networks a higher percentage of them are now secured and not open. Most are just WEP encrypted though and if I was up for nefarious activities it's one of the more simpler securities to get past.
Peter is you went 2km from Liverpool St Station you would have ended up in Dalston as one of your directions, I hope you did it during the day and didn't have your laptop on show, I didn't even used to like driving through there... apologies for anyone who lives in Dalston.
4. Richard
"Written ... whilst flying London to San Francisco."
I'm recovering from "Web-lag" after "attending" the interesting AlwaysOn Media Conference in New York, with its strange VC types - from the comfort of my own PC.
I now attend many seminars and conferences around the world, via the web.
(It's easiest to attend USA events during our evening, using my home PC & broadband, rather than ones during our working day.)
Are many other people doing this?
5. peter Cochrane
Iain = I get UK WiFi roaming for a flat fee of £5.80/month from my ISP - for any amout of use. Seems reasonable to me. Peter
6. Peter Cochrane
John = It is worth shopping around. Try The Cloud, BT, Last Mile, et al...and your fixed line ISP is always a good bet for a minimal WiFi Fee. My bill per month including international locations is less than £15/month. Peter
7. Peter Cochrane
Antony = Cabs are reasonably secure...the doors lock...but I generally avoid the tricky areas....and so do the businesses I engage with! My 2km in all directions was nominal/notional...and not perfacr or exact.
8. Peter Cochrane
Richard = I do this a lot too - probably every week - but I haven't counted. Sometimes I attend EU events when I'm in the USA! Peter
9. Michael Furey
"London and the UK"
You can't do a test JUST IN LONDON and then generalize to the UK. Are you serious?
10. Finbar Dineen
Just want to second some of the comments made. This 'research' applies solely to a small part of central London, since it only took place in a very small part of central London. Certainly not the UK as claimed.
More importantly, a lot of the apparently open wifi networks are not. A quick scan wouldn't tell you this. Any real attempt to connect to them will block you or ask for payment. I've scanned cities (Bath, Bristol, Edinburgh, Glasgow, London...) around the UK with my Nokia E61 and found the number truly open networks to closed is a ratio of about 1:20.
As I have said before, this is not the case in Budapest where the ratio is about 1:1.
You need to get out more and perhaps be more cautious with your conclusions based on the range and depth of your sampling.
I would love to have some real research data on this, rather than that based on a 30 minute taxi ride.
Conclusion: your conclusions are overstated and doubtful.
11. Peter Cochrane
Michaela = You missed a blog! I did a lot of the UK earlier - see:
http://networks.silicon.com/mobile/0,39024665,39165060,00.htm
Peter
12. Peter Cochrane
Finbar = You seem to have missed a blog
http://networks.silicon.com/mobile/0,39024665,39165060,00.htm
when I did an extensive sweep of the UK.
And I said the sites were open - no necessarily free. BUT I am seeing a much greater proportion of free sites than you experience - which in itself is interesting.
See all my previous responses for the minimal cost for access solutions I use.
Just off to lunch in Woodbridge Suffolk where the coffee shop provides free access...and Woodbridge is a small out of the way quaint place in Suffolk with a pub that provides CAT5 access too.
In my experience all you have to do is search....and find.
Peter