Mobile communication device maintaining lifetrails in a battery efficient manner
A method is used to develop and maintain a user's lifetrail, which is a historical record specifying the location of the user while in possession of a mobile communication device. A mobile device determines its current location by extracting a beacon ID from a signal source and transmitting it to a remotely-located server, which accesses a look-up table to find the corresponding location of the signal source represented by the beacon ID. The location may be specified in accordance with a spatial compression technique. The server transmits the signal source location back to the mobile device so that the mobile device knows that it is located within the coverage area of the signal source. Battery power is conserved by collecting the beacon IDs when it is receiving the beacon signals for some other purpose and not necessarily solely for the purpose of determining its current location. Battery power can be further conserved by deferring the resolution of the beacon IDs so that they are not necessarily associated with their corresponding location when they are received, but only at some later convenient time. In some cases resolution of the beacon IDs may be performed using social graph data received from a social network.
1. A method of recording a history of locations visited by a mobile communication device, comprising:
for each of a plurality of locations visited by the mobile communication device, while being located within a coverage area served by at least one signal source, wirelessly receiving a beacon signal from a plurality of signal sources having overlapping coverage areas and extracting a plurality of beacon IDs therefrom;
selecting a subset of the plurality of beacon IDs to be transmitted to a server;
upon occurrence of a predetermined event, transmitting the subset of the plurality of beacon IDs and timestamps associated therewith to the server; and
receiving from the server a location fix of each of the signal sources identified by the beacon IDs that have been obtained, said mobile communication device being located within a region surrounding the location fix equal to the coverage area,
wherein the subset of the plurality of beacon IDs is selected so that each signal source identified by a beacon ID in the subset operates in accordance with a different protocol.
2. The method of claim 1 further comprising storing each of the location fixes in a record that includes a history of previous locations visited by a mobile communication device as determined from locations of signal sources with which the mobile communication device has previously been in communication, said history of previous locations further including timestamps associated with the previous locations.
3. The method of claim 1 in which the predetermined event is selected to reduce power consumption by the mobile communication device in comparison to transmitting each of the IDs immediately upon receipt thereof.
4. The method of claim 1 in which the beacon ID is obtained by actively scanning for the beacon signal, the beacon ID being obtained when actively scanning for a purpose in addition to determining a current location.
5. The method of claim 4 wherein the purpose in addition to determining the current location is to gain access to a wireless network served by the signal source.
6. The method of claim 1 in which the predetermined event is receipt of a predetermined number of IDs and further comprising transmitting each of the IDs to the server after the predetermined number of IDs are received.
7. The method of claim 1 in which the predetermined event is receipt of external power and further comprising transmitting each of the subset of the plurality of beacon IDs to the server when the mobile communication device is connected to an external power source.
8. A server for determining a plurality of locations visited by a mobile communication device, comprising:
a locator component configured to receive from the mobile communication device over a communication network a plurality of IDs each identifying at least one signal source having a coverage area in which the mobile communication device is currently or was previously located and a timestamp associated with each of the plurality of IDs;
a signal source reference database configured to store a plurality of signal source IDs associated with a respective location of said signal sources;
a lifetrail database for storing a lifetrail record associated with the mobile communication device, said lifetrail record including a history of locations and timestamps associated therewith previously visited by the mobile communication device; and
computer-implemented processing logic to compare each of the plurality of IDs received from the mobile communication device to the signal source IDs stored in the signal source reference database, and if a match is found, adding the matching location and timestamp associated therewith to the lifetrail record associated with the mobile communication device,
wherein the locator component is further configured to receive the social graph data associated with a user of the mobile communication device,
wherein the social graph data maps the user to other users to which the user is connected through a social network,
at least one of the locations of one of said signal sources included in the signal source reference database being determined from social graph data received by the locator component, and
wherein the location information determined from the social graph data is used to annotate the lifetrail record of the mobile communication device.
9. The server of claim 8 in which the signal source reference database further includes at least one signal source ID whose location is unknown and said locator component is further configured to receive from the mobile communication device said at least one signal source ID and the location of said at least one signal source ID so that the lifetrail database can be updated to store an association between said at least one signal source ID and the location of said at least one signal source ID.
10. The server of claim 8 further comprising a map builder configured to construct one or more heat maps which show a frequency with which one or more user activities associated with usage of the mobile communication device occur at various locations.
11. One or more computer-readable memory devices, containing instructions which, when executed by one or more processors perform a method for recording a history of locations visited by a mobile communication device comprising the steps of:
for each of a plurality of locations visited by the mobile communication device, receiving over a communications network an ID identifying at least one signal source while being located within a coverage area served by the at least one signal source;
resolving each of the IDs identifying at least one signal source to determine a location of a corresponding signal source; and
creating a lifetrail record associated with the mobile communication device, said lifetrail record including a history of previous locations visited by the mobile communication device as determined from locations of signal sources identified by the IDs that have been received from the mobile communication device,
wherein resolving each of the IDs includes resolving at least one of the IDs from social graph data received from a social network, wherein the social graph data maps a user to other users to which the user is connected through the social network, and
wherein location information determined from the social graph data is used to annotate the lifetrail record associated with the mobile communication device.
12. The one or more memory devices of claim 11 further comprising sending the lifetrail record to the mobile communication device over the communication network.
13. The one or more memory devices of claim 11 further comprising;
receiving a value for an environmental parameter captured by the mobile communication device; and
refining a location of the mobile communication device within a coverage area of one of the signal sources using the environmental parameter.
14. The one or more memory devices of claim 13 in which the environmental parameter is selected from a group consisting of ambient temperature, ambient light and ambient sound.
15. The one or more memory devices of claim 11 in which the location of the respective signal sources is specified in accordance with a spatial compression technique.