One area that Windows Phone has been lacking so far is the ability to do anything with Bluetooth besides connect to hands-free headsets or speakers. Windows Phone 8 looks to finally expand Bluetooth functionality with the leaked SDK detailing some new features available to developers.
For instance, peer-to-peer file sharing is now allowed for apps that want to “talk” to each other. As an example, we could add an ability for the WPCentral app to share links or photos to another phone. Presumably this feature could be used for all sorts of features like in games by unlocking a feature when you pair up with another phone i.e. a social aspect...
"Windows Phone 8 Developer Preview introduces API that you can use to develop apps that communicate using Bluetooth. Using these API, an app can connect to another app or to a device. These core scenarios open up a wide range of possibilities that you can use to make your app more connected."
Bluetooth scenarios - Windows Phone 8 Developer Preview supports two Bluetooth scenarios: app to app, and app to device. In each scenario a StreamSocket connection is established between the apps or devices.
- App to app - In app-to-app communication, an app uses Bluetooth to discover another app that is advertising a service that the app wants to access. If the app finds another app within range that offers the service, the app initiates a connection request. When both apps accept the connection, a stream socket is opened between them, through which the apps communicate.
- App to device - In app-to-device communication, an app uses Bluetooth to discover a device that is offering a service that the app wants to access. If it finds a device within range that offers the service, the app initiates a connection request. When both accept the connection, a stream socket is opened between them, through which the app and the device communicate.
Peer discovery - Discovery is the process of finding a Bluetooth device or app that advertises a service with which you want to interact. In an app-to-device scenario, you can only discover devices that are already paired with the phone on which the app is running. Pairing is the process of using the Bluetooth control panel on your phone to find Bluetooth devices and then connect to them. Pairing typically involves sharing a PIN, or both sides