Handover

NFC Handover
The Bluetooth SIG defined a mechanism called “Secure Simple Pairing” ([BLUETOOTH_CORE], Volume 2, Part H, Section 7) to simplify the process of pairing two Bluetooth devices. Secure Simple Pairing defines four different association models, one of them using an Out-of-Band channel such as NFC.The NFC Forum Connection Handover technical specification ([CH]) defines the mechanism and format of the messages to exchange Alternative Carrier information between NFC Forum Devices or between an NFC Forum Tag and NFC Forum Device. Specifically, Bluetooth OOB data can be exchanged in Connection Handover Request and/or Select messages as Alternative Carrier information. For more details refer to http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf

The use of the NFC technology can enhance the user experience of applications that use the Bluetooth technology. The enhancements can be any of the following areas: 1. Select a Bluetooth device Discovering a Bluetooth-enabled device typically uses the Inquiry procedure to discover other Bluetooth devices in the vicinity of the discovering device. 2. Securely connect to a Bluetooth device NFC can simplify the process of authenticated pairing between two Bluetooth devices by   exchanging authentication information over an NFC link. 3. Start an application on a Bluetooth device NFC can be used to start an application to provide good user experience. For example, the user touches their NFC Forum device to another NFC Forum device to exchange contact information. Starting an application upon NFC ‘touch’ action is implementation specific

Negotiated Handover
Bluetooth Simple Pairing in NFC Forum Peer-to-Peer mode allows for mutual authentication based on commitments of public keys exchanged out-of-band. A device requesting handover to a Bluetooth carrier sends its public key commitment Hash C and Randomizer R with the Handover Request Message, and it receives the peer’s commitment and randomizer with the Handover Select Message.

Static Handover
A Static Handover can be used in cases where the Handover Selector device is equipped with an NFC Forum Tag only. Therefore, it cannot actively reply to a Handover Request Message. A Handover Requester device detects this message during the NFC discovery phase and will then be able to read data from the NFC Forum Tag. If the data that is read embodies a Handover Select Message, the Handover Requester can use this information to choose one of the indicated alternative carriers and try to establish a secondary connection

Starting NFC in sEVM Go to Settings menu Click More... Turn on NFC check box.

Validating Negotiated Handover
Turn on NFC on sEVM(Target device) Turn on NFC on Nexus phone(Test device) Open Gallery on the Test device Choose an image to transfer. Bring the 2 devices back to back. Test device will establish P2P connection with Target device Touch the image on Test device to beam on to Target device. Bluetooth will be turned on automatically in test and target device And image will be transfered using BT OPP.

Validating Static Handover
This can be validated using NFC enabled BT device like NFC BT HS device(Motorola Elite Flip) or using BT Tag writer apk. Install BT Tag write apk on the target device. start the application. Application will scan for BT devices then prompts the user to write the scanned device information on to Tag. Get the Tag(1/2/3/4 type) to the target device Tag writer apk will flash the data to Tag. Once the data is written. Get the tag near the Target device Target device will start handover app and allows the user to connect to Target device.