Content discovery and transfer between mobile communications nodes

• US 8,103,718 B2
• Filed: 07/31/2008
• Issued: 01/24/2012
• Est. Priority Date: 07/31/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: O'Shea, Gregory Francis, Zahn, Thomas Christian, Rowstron, Antony
• Primary Examiner(s): Dinh, Khanh
• Application Number:
  US12/183,460
• Publication Number:
  US 20100030840A1
• Time in Patent Office: 1,272 Days
• Field of Search: 709/203, 709/224, 709/228, 709/220, 709/226, 707/203
• US Class Current: 709/203
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems
• CPC Class Codes: H04L 63/123 received data contents, e.g. message integrity
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/104 Peer-to-peer [P2P] networks
• CPC Class Codes: H04L 67/1068 Discovery involving direct consultation or announcement among potential requesting and potential source peers
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes

Abstract

Content discovery and content transfer between mobile communications nodes is often required, for example, to synchronize maps, traffic hot spot information and the like for vehicle mounted satellite navigation devices, pedestrian hand-held personal digital assistants and other mobile communications nodes. In an embodiment, content discovery processes using data structures designed in particular ways and sent using a single packet enable nodes to identify files to be transferred whilst keeping overheads down. In an embodiment a first and a second data structure are used, each being formed from slightly different information about a subset of the files to be synchronized. In another embodiment a single tree-based data structure is used. A process for transferring data between two mobile communications nodes is also described.

Claims

1. A method comprising:

at a mobile communications network node of a mobile communications network having a first memory storing a plurality of files that it is required to synchronize with at least one other communications network node in the mobile communications network based upon a proximity of the mobile communications network node to the other communications network node;

automatically generating and sending to the other communications network node a packet comprising a first data structure, that first data structure being formed using file names and public keys of the plurality of files;

automatically generating and sending to the other communications network node a second data structure formed using the file names, the public keys and version numbers of the plurality of files; and

receiving from the other communications network node a packet comprising a data structure having details of any identified files of the plurality of files which are present in a second memory at the other communications network node with different version numbers.

2. A method as claimed in claim 1, wherein the first and second data structures are both sent in the packet.

3. A method as claimed in claim 1, wherein the data structures are based on Bloom filters.

4. A method as claimed in claim 1, wherein the first and second data structures are formed using information about only a partial number of the plurality of files.

5. A method as claimed in claim 1, which further comprising carrying out a content transfer process to synchronize each of the identified files with the other communications network node.

6. A method as claimed in claim 1, further comprising receiving a broadcast advert from the other communications network node, that broadcast advert being a packet comprising a first .global identifier and deciding whether to proceed with the sending of the first and second data structures on the basis of a comparison of the first global identifier with a second .global identifier of the communications network node.

7. A method as claimed in claim 6, wherein each of the first and second global identifiers formed using a file identifier and an instance identifier for each file in memory, the file identifier being formed using the file name and the public key for each file, and the instance identifier being formed using the file name, the public key and the version number for each file.

8. A method as claimed in claim 6, wherein the broadcast advert also comprises a total number of files in the second memory at the other communications network node.

9. A method as claimed in claim 8, which further comprises comparing the number of the plurality of files with the total number of files in the broadcast advert.

10. A method as claimed in claim 5, wherein the proximity location is within a communication range that allows wireless communication between the mobile communication network node and the other communications network node, and the content transfer process that synchronizes each of the identified files is triggered when the mobile communications network node enters the communication range with the other communications network node.

11. A method as claimed in claim 10, wherein the mobile communications network node and the other communications network node are in a joined state within the communication range as long as beacons are communicated between them.

12. A method as claimed in claim 11, further comprising:

transitioning the mobile communication network node from the joined state to a quiet state when communication with the other communications network node is terminated;

and performing active scanning to discover further communications network nodes in a content distribution cloud.

13. A method as claimed in claim 1, wherein the plurality of files include content relating to at least one of images, lists, maps, navigation data, road construction locations, safety camera locations, landmark locations, and/or points of interest locations.

14. A method as claimed in claim 6, wherein the broadcast advert announces the presence of the other communications node.

15. One or more computer-readable non-transitory storage media comprising computer-executable instructions configured to implement the method as claimed in claim 1.

16. A method comprising:

at a mobile destination network node of a mobile communications network having a first memory storing a plurality of files;

receiving an advert from a source network node upon entering a communication range with the source network node;

automatically generating a first data structure formed using file names and public keys of the plurality of files;

automatically generating a second data structure formed using the file names, the public keys and version numbers of the plurality of files;

sending the first data structure and the second data structure to the source network node in a first packet; and

receiving, from the source network node, a second packet comprising a data structure having details of any identified files of the plurality of files which are present in a second memory at the source network node with different version numbers compared to the version numbers of the plurality of files present in the first memory.

17. A method as claimed in claim 16, further comprising synchronizing each of the identified files after the mobile destination network node enters the communication range with the source network node.

18. A method as claimed in claim 16, wherein the plurality of files include content relating to at least one of images, lists, maps, navigation data, road construction locations, safety camera locations, landmark locations, and/or points of interest locations.

19. A method comprising:

at a source network node of a mobile communications network having a first memory storing a plurality of files;

broadcasting an advert announcing a presence of the source network node;

receiving, from a mobile destination network node at a proximity location within a wireless communication range, a packet including;

a first data structure including file identifiers of mobile destination network node files stored in a second memory on the mobile destination network node, the file identifiers being based on file names and public keys of each of the mobile destination network node files; and

a second data structure including instance identifiers of the mobile destination network node files, the instance identifiers being based on the file names, the public keys, and version numbers of each of the mobile destination network node files;

using the packet received, identifying a subset of the plurality of files which both the mobile destination network node and the source network node share, but for which the version numbers are different.

20. A method as claimed in claim 19, wherein the identifying further includes:

checking whether the mobile destination network node file identifiers match file identifiers associated with the plurality of files stored in the first memory; and

when a match is found, checking whether a source network node instance identifier is absent from the second data structure received from the mobile destination network node to identify the subset of the plurality of files.