Low energy beacon encoding
Techniques and tools are described for transmitting beacon messages using a wireless communication protocol, such as the Bluetooth Low Energy protocol. In some examples, beacon messages can be generated in a compact format and included in an AdvData portion of a payload of a protocol data unit of a Bluetooth Low Energy advertising channel packet. A beacon message can be transmitted from a stationary beacon generation device and broadcast to an area within a transmission range of the beacon generation device, and mobile computing devices, such as mobile phones, can receive the beacon message and perform one or more actions in response to information contained in the beacon message, all while conserving energy used by the beacon generation device and the mobile computing device.
1. A method for transmitting a beacon message using a Bluetooth Low Energy protocol, the method comprising:
generating, with a beacon generation device, at least one beacon message for transmission in an AdvData field of a payload of a protocol data unit (PDU) of a Bluetooth Low Energy advertising channel packet, wherein the at least one beacon message is defined by a beacon message format, the beacon message format comprising one or more type octets, the one or more type octets comprising a main type octet comprising a first bit followed by seven type bits, the seven type bits indicating an advertising type for the beacon message, the advertising type being one of a set of predetermined advertising types that indicate location-based information associated with a location of the beacon generation device, the first bit being either:
a first bit value, to indicate that the beacon message has no typed payload and that no subsequent type octets are present in the beacon message; or
a second bit value, opposite of the first bit value, to indicate that a subsequent one or more octets of the beacon message comprise a typed payload for the beacon message, the typed payload comprising a payload length field followed by payload data field, the payload length field being the length in octets of the typed payload; and
transmitting, with the beacon generation device, the at least one beacon message in an AdvData field of a payload of a PDU of a Bluetooth Low Energy advertising channel packet to a transmission area within a transmission range of the beacon generation device for reception by one or more mobile computing devices located in the transmission area.
2. The method of claim 1 , wherein the first bit is the second bit value and the beacon message comprises a typed payload, the typed payload comprising a payload length field followed by payload data field, the payload length field comprising up to five bits that indicate the length in octets of the typed payload.
3. The method of claim 1 , wherein the beacon message comprises an extension type octet preceding the main type octet, the extension type octet indicating that the advertising type is an extended advertising type.
4. The method of claim 1 , wherein the set of advertising types comprises one or more of: silent mode, flight mode, and hands-free mode.
5. The method of claim 1 , wherein the at least one beacon message is transmitted in an undirected advertising event.
6. The method of claim 1 , wherein the PDU is one of the following PDU types: ADV_IND, ADV_NONCONN_IND, or ADV_SCAN_IND.
7. A method for receiving a beacon message comprising:
receiving, with a mobile computing device, a beacon message transmitted in an AdvData field of a payload of a protocol data unit (PDU) of a Bluetooth Low Energy advertising channel packet, the beacon message being defined by a beacon message format, the beacon message format comprising one or more type octets, the one or more type octets comprising a main type octet, the main type octet comprising a first bit followed by seven type bits, the seven type bits indicating an advertising type for the beacon message, the advertising type being one of a set of predetermined advertising types that indicate location-based information associated with a location of the mobile computing device, the first bit being either:
a first bit value, to indicate that the beacon message has no typed payload and that no subsequent type octets are present in the beacon message; or
a second bit value, opposite of the first bit value, to indicate that a subsequent one or more octets of the beacon message comprise a typed payload for the beacon message, the typed payload comprising a payload length followed by payload data, the payload length being the length in octets of the typed payload; and
performing at least one action, by the mobile computing device, based at least in part on the location-based information without input from a user.
8. The method of claim 7 , wherein the first bit is the second bit value and the beacon message comprises a typed payload, the typed payload comprising a payload length followed by payload data, the payload length comprising up to five bits that indicate the length in octets of the typed payload.
9. The method of claim 7 , wherein performing at least one action comprises:
displaying a message to a user of the mobile computing device according to the advertising type of the received beacon message.
10. The method of claim 7 , wherein the mobile computing device is configured to receive the beacon message in sleep mode and process the beacon message in firmware without waking from sleep mode.
11. The method of claim 7 , wherein performing at least one action comprises:
in response to the received beacon message, wirelessly transmitting data comprising information specific to the mobile computing device or a user of the mobile computing device.
12. The method of claim 7 , wherein performing at least one action comprises:
in response to the received beacon message, wirelessly forwarding at least a portion of the beacon message to another computing device.
13. The method of claim 7 , wherein the mobile computing device is configured to adjust a local setting of the mobile computing device without input from a user based on the location-based information.
14. The method of claim 13 , wherein adjusting a local setting of the mobile computing device comprises switching the mobile computing device to a silent mode.
15. A computer-readable storage device storing computer-executable instructions for causing a mobile computing device to perform operations for receiving a beacon message, the operations comprising:
receiving a beacon message transmitted in an AdvData field of a payload of a protocol data unit (PDU) of a Bluetooth Low Energy advertising channel packet, the beacon message being defined by a beacon message format, the beacon message format comprising one or more type octets, the one or more type octets comprising a main type octet, the main type octet comprising a first bit followed by seven type bits, the seven type bits indicating an advertising type for the beacon message, the advertising type being one of a set of predetermined advertising types that indicate location-based information associated with a location of the mobile computing device, the first bit being either:
a first bit value, to indicate that the beacon message has no typed payload and that no subsequent type octets are present in the beacon message; or
a second bit value, opposite of the first bit value, to indicate that a subsequent one or more octets of the beacon message comprise a typed payload for the beacon message, the typed payload comprising a payload length followed by payload data, the payload length being the length in octets of the typed payload; and
performing at least one action, by the mobile computing device, based at least in part on the location-based information without input from a user.
16. The computer-readable storage device of claim 15 , wherein the first bit is the second bit value and the beacon message comprises a typed payload, the typed payload comprising a payload length followed by payload data, the payload length comprising up to five bits that indicate the length in octets of the typed payload.
17. The computer-readable storage device of claim 15 , wherein performing at least one action comprises:
displaying a message to a user of the mobile computing device according to the advertising type of the received beacon message.
18. The computer-readable storage device of claim 15 , wherein the mobile computing device is configured to receive the beacon message in sleep mode and process the beacon message in firmware without waking from sleep mode.
19. The computer-readable storage device of claim 15 , wherein performing at least one action comprises:
in response to the received beacon message, wirelessly transmitting data comprising information specific to the mobile computing device or a user of the mobile computing device, or wirelessly forwarding at least a portion of the beacon message to another computing device.
20. The computer-readable storage device of claim 15 , wherein the mobile computing device is configured to adjust a local setting of the mobile computing device without input from a user based on the location-based information.