The Privacy Implications of Mobile Sensor Networks

Back in February I gave a speech at Four Years From Now (FYFN) in Barcelona on the subject of privacy and mobile sensor networks. The full text of this speech is now available here on the OpenSignal website. Mobile sensor networks are an incredibly powerful tool to gather data about the world (as James Robinson and I have previously discussed) but their development raises important questions about privacy and the ways we interact in a world where internet access is both always-on and necessary for full social engagement.

OpenSignal is a sensor network company, and it is our responsibility to balance the opportunity of this new technology with privacy concerns, as we feel very strongly about our users’ right to privacy. Many of the concerns I raise in the speech are hypothetical, but on a more practical level there are three things we already do to help our users to participate in our sensor networks (OpenSignal, WeatherSignal, WifiMapper) while remaining informed about what is going on with our data.

1) Transparency

The traditional model for a data company is to offer a service (often free) to users and then take personal data and profit off it as a transaction cost of the user receiving utility from the service. We believe in both making explicit the data we collect and also feeding it directly into the service that we provide to users (signal data into coverage maps, pressure data available on etc). This allows users to directly benefit from the information they share. rather than simply giving it up as a cost, we want data sharing to be a benefit to our users. We believe we have done this very effectively.

2) Accountability

Users may be on board with our projects and be happy with sharing their data with us, but what happens to that data once it has been directly shared with us? While we do not collect any personally identifiable information (unless users explicitly log-in with facebook or send us an e-mail, neither of which are necessary actions for app usage), we still believe this question has relevance, especially for any company that collects location-tagged data (as we do – as we need to know where you can get good/bad signal or where your pressure reading is from – in order to provide our services). While the initial context in which data is given up may be fine to you (such as using our app), our sharing that data with third parties opens up avenues that are potentially difficult to navigate. For now we provide non-user identified data to mobile operators, consultancies and academic researchers. We believe our openness at point-of-use helps us here, as our business model is very open and obvious and the mobile network data we provide to operators helps them to improve their service to users – something which is the key driver of the OpenSignal mission.

3) Trust

We strive to be a company that has the full trust of our users, through our openness and clarity about our purpose. One of the things about collecting this kind of data is that you never know exactly what kind of use it might be put to (for instance, collecting battery temperature data as we do in OpenSignal led to our creating an algorithm to map ambient temperature from aggregated battery temperature readings – which directly led to the creation of WeatherSignal). We want to be a company that can be trusted to make the right decision with our users’ data, and we believe that all of our decisions up to this point have been made with user privacy at the forefront of our minds. I see no reason for that to change in either the near or far future.

Read the full report on privacy and the future of mobile sensor networks

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Free Wi-Fi Guide: London

To celebrate the launch of our new app WifiMapper we are releasing a series of posts on the WiFi hotpots in various global cities that we are most confident are free. WifiMapper is an app to help you find free Wi-Fi, with hundreds of millions of Wi-Fi hotspots in our database which we sort algorithmically in order to recommend hotspots that are both free and reliable. From our London database, then, the following ten were at the top of our list:

1) Balans Café, Old Compton Street
Password protected? Yes
Seen by 24 WifiMapper users

Balans is a small chain, with their first restaurant here in Soho. A recent comment on Foursquare recommends that you ‘get a royalty card’. We suspect they mean loyalty card (though the mere mile’s walk from Buckingham Palace might suggest otherwise) but either away turning up wearing a crown might prove rewarding. A potentially more useful note describes Balans as trendy with a good vibe and an excellent menu. All that and Free Wi-Fi, what more could you ask for?

2) Café Fiori, Charing Cross Road
Password protected? No.
Seen by 261 WifiMapper users

Fiori Corner is right next to Leicester square tube station, and so is mainly home to those waiting for their (late) friend to get off the Picadilly line or who have come to see the tourists in their iheartlondon t-shirts. It also houses those who have run out of mobile data and need to whatsapp their friends at 1am to say ‘meet me in the casino’ (side note – this has never happened to me).

3) National Gallery, Trafalgar Square
Password protected? No.
Seen by 134 WifiMapper users

It’s the National Gallery, it has paintings and a café. It also has Wi-Fi so you can look up the exact definition of ‘Chiaroscuro’, refresh your memory about the difference between pointillism and impressionism or Google the plot of the Da Vinci code so you can remember why the Renaissance was so important anyway.

It's the National Gallery

It’s the National Gallery

4) The Roebuck, Chiswick High Street
Password protected? Yes
Seen by 35 WifiMapper users

The Roebuck is a Chiswick pub that serves food, drink and, tastiest of all, free Wi-Fi. Old Foursquare comments advise trying the hot chocolate, which seems like a pretty poor recommendation for a pub but who am I to judge?

5) French House Bar, Soho
Password protected? Yes
Seen by 19 WifiMapper users

The French house is a fantastic pub in Soho that magically appears to be both always packed and always have one small table available upstairs in the corner. The Google Maps description calls it a ‘Francophile pub with a Bohemian crowd’. I’ve actually never tried its Wi-Fi network, but if the pub’s drinks are any indication it’ll probably be pretty reliable.

6) Camden Eye, 2 Kentish Town Rd, Camden Town
Password protected? Yes
Seen by 87 WifiMapper users

Pizza. Camden. Presumably a lot of skinny-jean wearing teenage hipsters. According to Foursquare it’s a ‘nice pub for a weekend afternoon to watch people go by’.

Don't go to France, stay here and drink instead.

Don’t go to France, stay here and drink instead.

7) TheContinentalBar_FREE_WIFI, King’s Cross
Password protected? No
Seen by 136 WifiMapper users

Ah, the vast expanse of Continental Europe. Separated from our proud little island nation by a thin sleeve of water. Don’t go there. Never go there. Drink in the bar and miss your train (or do what I did once and accidentally get on the train to Paris when you meant to go to Brussels).

 8) BFI IMAX FreeWiFi
Password protected? No
Seen by 46 WifiMapper users

(put on your 3D glasses now)

This text is big and it’s in 3D BE WOWED

Something something WiFi.

(take off 3D glasses).

9) BananaTree
Password protected? Yes
Seen by 13 WifiMapper users

You’ll go bananas for it HA HA HA HA HA HA HA HA



10) Bar Kick

Password protected? No
Seen by WifiMapper users

The name Bar Kick suggests a lot of possibilities. A Wi-Fi enabled Taekwando dojo? Fight club with better advertising? A bar where you have to do 56 kick-ups just to get a pint? Finding out that it’s a foosball bar is almost disappointing.

Photo Credit (in order) all from WikiMedia Commons:  Poco a Poco, Mark Ahsmann and ProjectManhattan

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App Update! WifiMapper iOS 1.0.3 released

A new version of WifiMapper on iOS is out! We’ve done a lot of work behind the scenes – it may not be immediately obvious, but the app is now smoother and slicker. We’ve really listened to you, our users – we’ve taken your forum comments, reviews, and emails and put each one in our development plan. Thank you as well to all of our testers, who have helped us ensure that the app didn’t break every time we moved a pixel.6zk5rgP9_400x400

So what’s in it? Life is like a box of chocolates, you never know what you’re going to get. With apps, on the other hand, you get to know EXACTLY what you’re going to get. Here we go:

1) Better filtering of Wifi hotspots – we’re showing better hotspots and better groupings of multiple routers. We’ve also incorporated your data, so if you’ve contributed hotspot classifications, take a look – they should be there.  Further refreshes are planned to occur once a week.

2) Buttons! So while you shouldn’t be pushing other people’s buttons, there are more parts of the app for you to explore. We’ve tried to make things clearer and easier to navigate.

3) Dynamic information – Whether the performance is good or bad, it’s a cafe or park, now you’ll get more clarity on how we assign these labels and where the information comes from.

4) Map and Search – In an unfamiliar place? Looking for something specific? We’ve optimised the search to handle these cases better.

Enjoy, and let us know what you think, either below or in the WifiMapper forums. Also, the next app update will be a big one (version 1.1!) and will include email login (we heard you when you requested login options other than Facebook), a redesign of the profile page, and other features. Help us steer the ship by joining the WifiMapper iOS beta program. If you’re on Android, you can join the active public beta through the WifiMapper Google+ community. The official release of WifiMapper Android will be in a few weeks – hang on in there!

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The connected car: A primer

If you’ve shopped a new a car in the last few years, chances are you’ve been presented with a lot more options beyond leather seats and fancy speakers. Cars are getting connected, giving drivers the ability to bring apps and internet services once confined to smartphones and PCs into their dashboards.

Given the amount of time we spend behind the wheel, linking our cars to the cloud and the apps we use for information and entertainment makes a lot of sense. But keep in mind that the automotive industry is much more conservative and plodding than the fast-paced world of Silicon Valley. Features and services will come much more slowly to the dashboard than they will to your iPad.

The automakers do have reason to be cautious. We’re often engaging with our infotainment systems at highway speeds. An app that proves to be too cumbersome to use or too distracting (don’t expect to see YouTube on your heads-up display any time soon) could prove fatal. Still, in many new cars you can now turn on Pandora or many other streaming audio services with a touch of the screen or even a voice command. That’s nothing to scoff at.

If you’re thinking of making a connected car purchase, here are a few things to keep in mind:

  • Car connectivity can mean one of two things. Either your automaker has embedded a 3G or 4G radio into the vehicle or it provides the means for you to connect the dash to the internet through your smartphone. Embedded connectivity can often mean a better signal and faster connection through the car’s externally mounted antenna, it can come with some added telematics features (for instance, letting you see your fuel level from a remote app) and it can turn your vehicle into a Wi-Fi hotspot. But it also requires getting a separate – and often expensive – mobile subscription for your car. With bring-your-own-connectivity you’re basically using the same connection and mobile plan attached to your smartphone.
  • The number of apps available in cars are still tiny in number. If you thought the smartphone market was fragmented, well every automaker has a different operating system and app requirements, making it a nightmare for developers. While a few companies like Pandora (which aims to become the new FM radio of our cars) will go through the effort of optimizing their apps for 20 different infotainment platforms, most will not. Also, the automakers may block certain types of apps for competitive reasons. Wouldn’t it be wonderful to use Google Maps, Waze or Here for turn-by-turn directions in your car? Well, that’s not wonderful for automakers trying to protect the profits from their embedded navigation systems.
  • The connected car you get when your drive off the lot is probably the one you’ll be stuck with for a long time. We trade in our smartphones for newer models every year or two, but typically we own our cars a lot longer. While automakers will be able to offer some enhancements through software upgrades, the hardware in your car is going to become outdated before you know it.

If you’re a heavy user of Google or Apple services and want to use them in your vehicle, then it might be worthwhile putting off your new car purchase a bit longer. This year, the first cars supporting Apple’s CarPlay and Google’s Android Auto will hit the market. Don’t expect either platform to recreate the iOS or Android experience on your dashboard. They’re not true infotainment operating systems. Instead, they project a scaled-down and car-optimized version of the phone’s user interface into the dashboard display, letting you use Google and Apple’s mapping, media and communication services without fiddling with your handset.

I don’t think any reasonable person would make a car purchase today solely for the type of apps it supports, but I suspect it will become an increasingly important consideration as car connectivity gets more sophisticated. After all, we spend a lot of time in traffic in our daily commutes. That’s a lot of time in which we want we to be both informed and entertained.

Editor’s note: This is a guest post by Kevin Fitchard who is a journalist covering the mobile industry and wireless technology. He most recently wrote for Gigaom.

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No Signal?! How about a new cell tower…

Continuing with the theme of solutions for no signal (started by the post No Signal?! Top things to try), I’d like to explore a much more permanent option for improving signal, albeit one that takes much longer and has a much smaller likelihood of ‘actually happening’. This option is the construction of a new cell tower.

Okay, that’s obviously not something YOU can do on a whim. But what if you live in an area with poor signal, and you’d be happy with a new tower on your property? How do you start? Who do you talk to? In this blog post, I am going to explain the processes and considerations of different players when building cell towers, using examples of specific companies from the United States. However, you should be able to extend this to your country by looking for the same types of companies and organisations.

1) The First Steps
The first thing you should do if you are willing to lease your property for a cell tower is register your intent, either with a tower infrastructure company (such as Crown Castle or American Tower), or with the network providers themselves. Some network providers will have their own infrastructure branches, as you can see with T-mobile’s Real Estate arm.

What does registration entail? Options for Registering Intent for a Cell TowerIt’s pretty straightforward – basically address, GPS coordinates, and type of property. If we take a look at the registration form of Crown Castle, we can see that there are several default property types (namely, tall constructions as well as land parcels). This makes sense, given that there are several types of tower deployments – standalone towers, rooftop installations, small cell deployments, and collocations (placing of new antennas on an existing tower).

2) The Decision Process and Limitations 
Now that you’ve registered your intent, it is up to the tower company to decide whether to consider your land for a new cell tower location. Tower infrastructure companies look for new tower locations based on the requirements of network providers, and as American Tower states, they will “contact you directly if there is serious interest in utilizing your land to develop a tower site.” So what are the chances? What do they look for in a tower site? While the full list depends highly on the context, here are a few common themes:

  • Your property is inside the ‘Search Ring’ – the area defined by the carrier as needing a cell tower.
  • Topography and position of your property (elevation, easy/difficult construction area, access to cell site)
  • Size of property in relation to tower requirements – different kinds of towers have different free area requirements.
  • Types of Transmission TowersZoning – Zoning determines restrictions on constructions above a certain height, but also, specific communities can have “individual” regulations on cell tower construction due to visual aesthetics and health concerns. At the same time, cell towers – a ‘public utility’ – might be so important that zoning regulations can be overruled. There’s a very interesting summary on “Municipal Zoning of Cell Towers and Antennas” by the Office of the General Counsel in New York.

While your property might fit these specifications exactly, there are other considerations that may affect your chances of getting a tower built on your land. As posted by the FCC (US telecoms regulator), the tower location must be compliant with:

  • The National Environmental Policy Act (NEPA) – the tower site must not adversely affect:
    • threatened or endangered species
    • designated critical habitats
    • migratory birds
  • The National Historic Preservation Act (NHPA) – the tower site must not adversely affect historic properties or tribal lands

3) Offer Made, Lease Negotiations
Assuming your property passes the above requirements and fits the tower company’s specifications, you may receive a lease offer. Whether and how much you negotiate is again dependant on context – are there other good options for the tower company to construct the tower? You could consult a tower lease consultancy – Steel in the Air and Airwave Advisors are two examples- to help you with the negotiations. An interesting important detail to remember is future co-location rents: if a tower can support more antennas than are initially installed, you could get an increase in your lease when other networks install their antennas on the same cell tower. For you to receive collocation rents, the appropriate terms need to be part of your lease agreement.

That’s the basic process of getting a tower company or network to build a new tower, or collocate an antenna, on your property. Do you have a tower on your property? Did you have an experience similar to the one described here? Please share below or in the OpenSignal forums!

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Data throttling: Why operators slow down your connection speed

You’re surfing on a wide-open 4G connection and suddenly see data speeds slow down to a snail’s pace. Mobile networks often experience big fluctuations in performance, but this downgrade remains persistent – say for several days – and then your speeds return to normal as if nothing had happened. Does this sound familiar? Congratulations, more likely than not, you’ve been throttled.

Throttling is the act of a mobile network operator purposely curtailing the speed of your connection in order to limit the amount of data you consume. Those speeds sometimes are as low as 32 kbps, but more often than not they compare to the ones you’d see over a 2G network. Throttling doesn’t sound very nice, and it’s a constant source of resentment from consumers. But throttling isn’t always an inherently evil act.

For instance, many carriers will only throttle your connection once you’ve gone over your monthly data allotment. Instead of merely shutting off your data connection or automatically billing you for another bucket of megabytes, they’ll keep you connected –albeit at very sluggish speeds – so you won’t lose access to the internet entirely. For customers on a tight budget or who are unwilling to top off a data bucket with only a few days remaining in a billing cycle, this kind of throttling policies offer a data lifeline.

It’s not a universally accepted policy though. A recent report from MobiForge shows that carriers in some countries – the U.S., Germany and Spain for instance – adopt throttling policies, while in others – like the U.K. – carriers tend to charge for overages.

But some carriers also use throttling as a means of shaping their network traffic, in essence slowing down some customers data rates in order to free up network capacity for other customers. In the U.S. it’s become a very controversial practice, and usually it applies to so-called “unlimited” plans offered by big operators like AT&T and Verizon as well as many of the prepaid brands like TracFone.

Both AT&T and Verizon have phased out unlimited plans from their regular service menu, having introduced them in a day where it was inconceivable that customers could ever consume more than a few gigs of data in a month. But there are still millions of customers grandfathered into those all-you-can-eat plans, and many of them are discovering their unlimited service is limited after all.

These operators claim throttling policies prevent a handful of users from dominating a majority of their network’s resources, and in Verizon’s case it only uses throttling on its 3G network when it’s congested (Verizon scuttled a plan to apply a similar policy to 4G last year). But these customers were promised an unlimited plan, and that’s not what they’re getting. Consequently, U.S. trade regulators have stepped in, accusing these operators of misleading their customers.

No matter how it’s implemented, throttling can have an impact on how a large portion of customers access the network. Using its performance testing data, OpenSignal analyzed the 4G connection speeds of one operator known for throttling back speeds. It found a fairly even distribution of average connection speeds between 400 kbps to 17 Mbps, which is what you’d expect to see in any network. But right at the 250 kbps mark, there is a huge spike in the proportion of users connecting to the network at sluggish bandwidth. At this operator (which OpenSignal isn’t naming), as many as 10 percent of customers are seeing their connections throttled at any given time.

This is what throttling looks like

This is what throttling looks like

Throttling is a practice that should disappear as it ultimately encourages the idea of mobile data scarcity. What we should be doing is promoting the idea of data abundance.

Even in the cases in which throttling keeps customers connected when their data plans dry up, the policy is a poor substitute for operators simply offering reasonably priced data that would allow you to maintain your regular 4G connection. Operators that charge you to top off your data plan, typically do one of two things. They either sell you a big bucket of data – say $15 for 1 GB – even if all you need is 50 MB to get you to the end of your billing cycle. Or they charge punitive incremental rates, for instance 10 cents per megabyte, which works out an astronomical $100 for a single gigabyte of data.

Imagine if gasoline or petrol was sold the same way as mobile data: After you exceeded your monthly allotment of 10 gallons, you’d either be charged an exorbitant rate for the 11th gallon or your car would be restricted to 10 mph speeds for the remainder of the month.

Whether operators like it or not, mobile data is a commodity and it should be sold like one. We’re starting to see the mobile industry grudgingly prodded in that direction. One of the most revolutionary things about Google’s new mobile service Project Fi, in my opinion, is that it charges flat rate pricing. In the U.S. you pay $1 for 100 MBs of data no matter how much or how little you consume. If all mobile operators would do the same thing, then there would be no need – and no possible justification – for throttling.

Editor’s note: This is a guest post by Kevin Fitchard who is a journalist covering the mobile industry and wireless technology. He most recently wrote for Gigaom.

Posted in LTE, Mobile Trends, Understanding signal | 1 Comment

The key to a faster network: A smaller network

We’re accustomed to seeing the cellular networks looming above us – big antennas mounted on towers, masts and the rooftops, beaming down their signals from up on high. But the mobile network soon will start taking on a more human scale.

The mobile industry is miniaturizing the basic building block of mobile networks: the cell. These so-called small cells work the same way as big macrocells. They offer the same speeds, carry the same capacity and host the same phone calls as their tower-mounted counterparts. The difference is they cover a lot less ground.

That’s important because the mobile network is ultimately a shared network. Just because that LTE tower in the distance can support 100 Mbps, it doesn’t mean you’re ever going to see anything close to that speed on your smartphone or tablet. That capacity is sliced and diced up among all of the devices connecting to the tower at any given moment. However, once you start shrinking down the radius of each cell, then far fewer devices are linking to it. There are fewer resources to share, and everyone enjoys faster speeds. Any single small cell isn’t going to add much capacity to the network, but when you start deploying them in dense clusters, those capacity gains are substantial.

As an example, let’s say a macrocell with a one square-mile radius offers up to 100 Mbps in LTE capacity. A cluster of 20 small cells covering roughly the same area would support – theoretically at least – 20 times this capacity.

Consequently, mobile operators are eyeing small cells as a means of layering immense quantities of 4G capacity in areas where data demand is highest: urban corridors, high-traffic indoor areas and commercial districts. For example, Verizon has begun a small cell rollout in the main tech company corridors of downtown San Francisco, mounting them on utility poles on a block-by-block basis.

The macro network isn’t going away. Those big towers provide the coverage necessary to make our devices truly mobile. But in dense cities, those macrocells eventually will act more like big umbrellas. They’ll ensure we can get signals in our cars and in our less dense residential neighborhoods. They’ll provide network glue as we move between clusters of small cells. That coverage continuity will be crucial, but small cells will do most of the heavy lifting when it comes to data traffic.

There are still some technical obstacles the industry must overcome before we get that multi-layered network. When you start sticking small cells under that macro-network umbrella you inevitably get interference. One of the biggest problems the mobile industry has to sort out with small cells is ensuring that they play nice with their larger counterparts. But new standards developed for 3G and 4G networks are promising to keep that interference in check.

The small cell transformation won’t happen overnight, but many global operators are already deploying these tiny base stations in the urban fabric of our cities. Vodafone is sticking small cells on billboards and street furniture in Amsterdam. AT&T is installing them in malls, stadiums and pedestrian areas in major U.S. cities (it’s even putting them in Disney World).

So if you happen to see some strange box pop up on a neighborhood utility pole, you may want to check your phone. You might find you’re getting a much stronger signal.

Editor’s note: This is a guest post by Kevin Fitchard who is a journalist covering the mobile industry and wireless technology. He most recently wrote for Gigaom.

Posted in Understanding signal | Tagged | 2 Comments

State of LTE June 2015

Today we release our most recent version of the OpenSignal State of LTE report. We are now releasing this report every three months, as a way of keeping a close eye on the development and improvement of LTE around the world.

The world’s fastest country for LTE is Singapore, which averages 24Mbps. TDC, Denmark is the fastest overall single network with its users experiencing speeds of 28Mbps. For LTE coverage the South Korean networks still rank as the best in the world, averaging 95% time on LTE, with LG U+ the best performing of all of them averaging almost total effective coverage at 99% time on LTE.

The US networks rank around in the slower half of global networks, with a country-wide average of 7Mbps (T-Mobile are again the fastest US network, averaging 10 Mbps) but are the 7th best country for effective coverage, with Verizon users experiencing 87% time on LTE.

To see where other countries and networks rank read the full report.

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Stingrays: The new mobile tool of the surveillance state

If you thought the ocean was the only place you should be wary of stingrays, then think again. Stingray is the term first coined by Harris Corporation for a surveillance device it developed to intercept mobile phone signals. It was first used by intelligence agencies and militaries to combat terrorism, but in the U.S. the technology is increasingly being used by the FBI and law enforcement agencies to track any person of interest. Understandably, it has civil libertarians and privacy advocates angry.

Unlike a wiretap targeting a specific phone number, Stingrays and similar devices are being used in dragnet style operations, pulling information from any nearby phone – regardless of whether it belongs to an intended surveillance target – out of the airwaves. Stingrays do this by simulating a cell site, forcing a phone to connect to it instead of a legitimate operator’s network. From there it extracts each phone’s unique International Mobile Subscriber Identity (IMSI) numbers, which can be used to track a specific device no matter where it roams.

It’s hard to know exactly what additional information Stingrays collect. The manufacturers of these IMSI catchers are not only super-secretive about their exact capabilities, but they have also forced agencies using them to sign non-disclosure agreements preventing them from revealing any details about how they operate. In fact, an investigation by The Guardian and the American Civil Liberties Union found that prosecutors have dropped criminal charges in many cases in order to avoid spilling the beans about Stingrays in court.

It’s possible, though, that Stingrays can collect far more than unique phone identifiers. There are reports of Stingrays being used to turn off the phone’s normal call encryption or gathering data stored inside the phone. In addition, a Stingray feasibly could be used to relay a call or data stream between a legitimate phone and a legitimate cell tower. In such a case it would be acting as a “man in the middle” hack, monitoring every conversation or bit transmitted to the network.

Just how widespread Stingrays are used is also not certain because of the secrecy surrounding them. So far most cases have been reported in the U.S. – the ACLU has identified 52 agencies in 22 states – but that doesn’t mean they’re not being used by other governments for surveillance. After all, these devices are most useful when the public isn’t aware of their existence.

So if you don’t want to be the unwitting target of mass mobile phone surveillance what can you do? To be honest, not much. So long as you have a phone that connects to the cellular network, it appears a Stingray can intercept your connection and identify your device. Let’s face it: our phones have always been big beacons advertising our locations to anyone with the proper equipment. It’s why in action thriller movies you always see everyone taking out their phone batteries and removing SIM cards. Only when a phone’s dead is it not revealing any information on its location.

But there may be some measures you can take against some of the other purported surveillance capabilities of Stingrays. Instead of relying on your carrier’s standard voice and messaging services, you can download apps that use alternate encryption to make calls and send texts. Open Whisper Systems, a non-profit group developing secure communications software, has several apps in that vein, including RedPhone, Signal and TextSecure.

If you’re willing to go even further, you can invest in one of the new ultra-secure smartphones in the market, like Silent Circle’s Blackphone or GSMK’s CryptoPhone. Even these highly secure gadgets won’t let you avoid Stingrays entirely, but GSMK has developed firewall software that detects if its phone is connecting to a fake cell site.

Probably the best thing you can do to stop Stingrays’ growing use, though, is tell your Congressman or MP, your police representatives or elected county sheriff that the public won’t tolerate a mass surveillance state.

Editor’s note: This is a guest post by Kevin Fitchard who is a journalist covering the mobile industry and wireless technology. He most recently wrote for Gigaom.

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Updated Data Collection Format

One of the great things about the OpenSignal Android app is that you, our users, have access to the data that you are sharing with us about your network. So, if you want to do your own data analysis on the signal in your area, practice your mapping skills, or have raw records to show your network about poor service, you can. This post will be about explaining all of the columns in the dataset (and is an updated version of this original data format post). To export your data, click “Settings” on the menu, then scroll down until you see “Export Data”. After you click “Save Data to SD card”, you’ll find the exported csv file in the “opensignalmaps” folder in your phone’s file system.

Here’s what you’ll see in the exported file:

Column Index Field Definition
1 _id Row identifier, used internally in the app. In each exported file the number will be unique to each row. So it could be useful to you if you need a key, or to search for rows.
2 network_type Network signal type – HSPA, LTE, EDGE, GPRS etc. Note it doesn’t report WiMAX – the app considers this as non-voice data. If you’re interested in checking this see ‘network_connection_type’.
3 network_type_int Number reported through the Android API that corresponds to one of the above network types.
4 network_name Name of network sending signal data (as seen by the hardware of the phone – this field will only have MNOs, not MVNOs).
5 network_name_sim Network name registered on the phone’s SIM card (this is the ‘home’ network and will include MVNOs).
6 roaming 1 – Roaming; 0 – Not roaming; -1 – unknown.
7 psc For UMTS phones this is the Primary Scrambling Code in 9 bits (UMTS format). For CDMA phones this will be the System ID (SID). -1 for unknown or error.
8 network_id Usually 6 digits with the first three being MCC (mobile country code) and the last 3 being MNC (mobile network code). An ID unique to each network. (MNOs only)
9 network_id_sim The Network ID of the SIM card. Usually 6 digits with the first three being MCC (mobile country code) and the last 3 being MNC (mobile network code). An ID unique to each network. (MNOs and MVNOs)
10 my_lat Last known latitude of the phone when signal was detected. 0 for unknown.
11 my_lon Last known longitude of the phone when signal was detected. 0 for unknown.
12 my_altitude Last known altitude of the phone when signal was detected. 0 for unknown. -9999 for error or unknown.
13 loc_source_gps_one_net_zero Indicates whether the location was provided via the GPS (1) or by using network information such as wifi or cell triangulation (0). -1 if not known.
14 location_inaccuracy Accuracy of the location, in meters, at the time of the location fix (according to the location provider). 0 for not known.
15 location_age The ‘age’ of the location fix in milliseconds – the time between the location fix and the tower being seen.
16 location_speed The speed of the phone when the location fix was taken, in metres per second. -1 or 0 for unknown.
17 include_alt_loc Indicates if a value for altitude is available.
18 my_lat_net If no GPS fix is available, the above fields (my_lat, my_lon etc.) will use the network values (location based on wifi or cell tower triangulation). If a GPS fix is available we also ask for the last network location – and report it here if one is available.
19 my_lon_net  See above
20 my_altitude_net  See above
21 location_inaccuracy_net  See above
22 location_age_net  See above
23 location_speed_net  See above
24 current_cell This is 1 if the tower corresponding to this row was actively connected – i.e. if it was dealing with your telephonic data. It is 0 if the tower was seen by your phone, but your phone was not using it actively for voice data – probably because another stronger signal source was available.
25 bit_error_rate Values range from 0-7. -1 or 99 for error or unknown. This is only available for GSM networks, see the 3GPP Standard TS 27.007 8.5.
26 rssi Received Signal Strength Indicator. On a scale from 0 – 31. To convert to dBm use dBm = (RSSI*2 – 113).
27 timing_advance LTE timing advance
28 cell_type The cell tower type (LTE, GSM, CDMA). Note: a device can be connected to an LTE and GSM/CDMA tower simultaneously
29 CID For GSM phones, this is the cell tower ID. For CDMA, this is the BSID or base station ID.
30 LAC Location Area Code for GSM phones. For CDMA it is the CDMA network identification number.
31 cell_id_3 The PCI for LTE cell towers, otherwise left blank.
32 cell_lat Latitude of the cell tower (according to OpenSignal’s tower database, and may not be fully accurate).
33 cell_lon Longitude of the cell tower (according to OpenSignal’s tower database, and may not be fully accurate).
34 bg_scan This column value is 1 if this reading was taken with the app running in the background, otherwise it is 0.
35 timestamp Timestamp of a signal reading as a UTC timestamp (milliseconds since 1970-01-01).
36 timezone_offset Offset from UTC in milliseconds due to time zone differences.
37 dst_offset Offset from UTC in milliseconds due to daylight savings time.
38 connection_type The network data connection type: 0 for mobile/none, 1 for wifi, 6 for WiMAX.
39 run_speed OpenSignal settings indicator for the frequency to collect data. Matches data collection settings in Settings page. Values from 0 to 4.
40 battle Legacy field – whether or not phone was in turbo (or ‘battle’) mode.
41 evdo_snr This is specifically for EVDO (a type of CDMA 3G) connection. SNR is the signal-to-noise ratio.
42 cell_lat_cdma If the tower detected is a CDMA tower, this is the broadcast latitude.
43 cell_lon_cdma If the tower detected is a CDMA tower, this is the broadcast longitude.
44 measurement_id Field that allows grouping of rows such that the current cell and neighbouring cells at the point of an observation are given the same measurement ID.
45 time_at_value Experimental field – how long have you been connected to a cell tower.
46 exact_time Legacy field.
47 apv App Version
48 ssid Wifi Network SSID
49 bssid Wifi Network BSSID
50 rsrp Value for LTE Reference Signal Received Power.
51 rsrq Value for LTE Reference Signal Received Quality.
52 rssnr Value for LTE Reference Signal Signal-to-Noise Ratio.
53 cqi Value for LTE Channel Quality Indicator (in dBm).
54 call_state Whether or not there is an active call.
55 scrn_state Screen state
56 data_enabled Whether or not Mobile data is enabled or has been disabled by the user.

Hope this helps! We’d love to know what kinds of projects you use the data for – share here or in the OpenSignal Forums. Thanks!

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