How Does Cell Phone Contact Tracing Work?

Contact tracing is part of the process of supporting patients and warning contacts of exposure in order to stop chains of transmission. It works by logging when two people have been in close proximity to each other for a substantial period of time. If one of the users is later diagnosed as having the disease, an alert can be sent to others they have recently been close to, telling them that they should also get tested and/or self-isolate.

The Apple-Google model carries the process out on the handsets themselves, making it more difficult for the authorities or potential hackers to de-anonymize the records and use them for other means.

Digital contact tracing replaces at least some of those interviews with technology. Especially in South Korea and China, it's been an effective way to keep infections down. (South Korea is finally down to zero local infections.) But the successful approaches used elsewhere rely on a level of trust in authority and giving up privacy, which may not be acceptable in the individualistic United States.

Your mobile phone carrier can track your location at all times, by analyzing cell tower connections. This depends on the cell signal strength.  In South Korea, when someone is diagnosed with COVID-19, those tower hits are being shared with local governments, which combine them with CCTV footage, credit card receipts, and interviews, and broadcast the results on the web and through text messaging.

Bluetooth-based contact-tracing apps such as Singapore's TraceTogether rely on phones running the app in the background, searching for nearby Bluetooth devices also running the app—that's how Apple's AirDrop works. Phones can roughly determine the distance between each other based on Bluetooth signal strength; recent iPhones can also use their U1 ultra-wideband chips to figure out their proximity to each other. Unlike the network and QR-code-based solutions, Bluetooth-based apps drain your phone's battery.

New Weather Channel App Notifies You When Cell Networks Are Down

New Weather App Can Spread Urgent Alerts Even When Cell Networks Are Down. 

The Weather Company’s new Android app uses mesh networking to spread data between phones over Wi-Fi and Bluetooth. IBM, The Weather Company launch mesh-powered app for internet-poor regions.

Having a wealth of up-to-the-minute climate data at our fingertips is something most of us take for granted. Thanks to a reliable cell connection, our smartphones, and the work of hundreds of meteorologists and climatologists around the globe, keeping abreast of an incoming storm isn’t so much a matter of how, but how quickly. Unfortunately, though, that isn’t the case for everyone.

In developing countries, cellular connectivity is congested, intermittent, and in the worst cases inaccessible. That’s why IBM, in collaboration with developers at The Weather Company, introduced Mesh Network Alerts, a new technology that provides a peer-to-peer means of facilitating communications between residents of underserved nations.

Mesh Network Alerts work by linking mobile devices directly to one another, daisy-chaining handsets in a sort of node network. Using a combination of Bluetooth and Wi-Fi, each connected smartphone stores and propagates messages to devices within a 300- to 500-foot radius, creating a mesh that can effectively reach more devices. Read more

Bluetooth Beacons Are Used Like Mobile Phone Cookies

Bluetooth Beacon Transmitter

Bluetooth proximity marketing is the latest marketing technique being deployed by retailers, Governments and sporting venues to track users.  How these groups benefit from it?  They do it through proximity marketing and it is about connecting with your audience at the right place and time.

Bluetooth is a short-range wireless system found on most smartphones and tablets that transmit information and can receive information.  Most people currently use Bluetooth for hands free in our cars or to connect to a wireless speaker. Bluetooth proximity marketing involves setting up Bluetooth "broadcasting" equipment at a particular location.  If your Bluetooth is "turned on" and you are near one of these beacons.  Information can be sent to devices via be text, images, audio on enabled devices (aka cell phone, tablet) within range of the transmitter (beacon).  A Bluetooth enabled mobile device, when in range of the beacon (transmitter) receives the signal and then via the device's operating system, passes information to the appropriate mobile app(s).

Several things need to happen beforehand.
1)  Bluetooth is turned on
2)  A Bluetooth beacon transmitter must be nearby
3)  The targeted individual should have a specific application installed on the their phone that is capable of receiving a push notification.  

What information is collected?
1) The ID of the phone and user of the phone
2) Cellular or Wifi signal strength issues
3)  Locations traveled of other beacons in the area (for example locations within a store).