System and method for updating location information for distributed communication devices

• US 6,597,915 B2
• Filed: 12/18/2001
• Issued: 07/22/2003
• Est. Priority Date: 12/18/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Huang, Jian, Callaway, Edgar H. Jr., Shi, Qicai
• Primary Examiner(s): Nguyen, Lee
• Assistant Examiner(s): Milord, Marceau
• Application Number:
  US10/022,944
• Publication Number:
  US 20030114168A1
• Time in Patent Office: 581 Days
• Field of Search: 455/456, 455/458, 455/67.1, 455/343, 455/573, 455/574, 340/825.49
• US Class Current: 455/456.1
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 84/22 with access to wired networks

Abstract

Location related information is collected for a network of communication devices that each is operable in a coordinating mode and in a non-coordinating mode. While in the coordinating mode, each communication device collects and stores location determining information (410, 420). Using the location determining information collected by one or more of the communication devices over multiple instances of operation in the coordinating mode, location information is calculated or updated for selected devices within the network (510, 520, 530, 540). In one embodiment, each device operates to mediate communication activities among others devices of the network while in the coordinating mode.

Claims

1. A method of updating location information for communication devices that are spatially distributed, the method comprising the steps of:

at each of a plurality of communication devices and at multiple instances over a period of time, alternatively operating in first, second, and third distinct modes, wherein the first mode comprises sleeping for a particular period of time, the second mode comprises waking up and performing a particular function, and the third mode comprises communicating with others of the plurality of communication devices and collecting and storing location determining information; and

updating location information for selected devices of the plurality of communication devices device based on location determining information collected by at least one of the plurality of communication devices over multiple instances of operation in the third mode.

2. The method of claim 1, further comprising the steps of:

detecting that a particular device of the plurality of communication devices has a change in location by comparing location determining information collected by at least one of the plurality of communication devices during multiple instances of operation in the third mode; and

updating location information for the particular device in response to a detected change in location.

3. The method of claim 2, further comprising the step of uploading to a centralized processor, by selected devices of the plurality of communication devices, location determining information for communication devices having a change in location for determining relative location information for the plurality of communication devices.

4. The method of claim 1, further comprising the step of coordinating communication activity for others of the plurality of communication devices while operating in the third mode.

5. The method of claim 4, wherein the step of coordinating further comprises the step of managing timing schedule activity for others of the plurality of communication devices while operating in the third mode.

6. The method of claim 1, further comprising the step of operating the plurality of the communication devices such that only one of the plurality of communication devices function in the third mode at any particular time.

7. The method of claim 1, further comprising the step of in at least one of the plurality of communication devices, selecting a time to operate in the third mode via an independent, random process.

8. The method of claim 1, wherein the location determining information comprises signal quality information for communication signals received from another of the plurality of communication devices.

9. The method of claim 8, wherein the signal quality information comprises received signal strength information.

10. A method operating a plurality of communication devices, the method comprising the steps of:

at a particular device randomly selected from the plurality of communication devices and at multiple instances over a period of time, alternatively operating in a coordinating mode for coordinating communication activity among the plurality of communication devices, and a non-coordinating mode, in which coordination for communication activity is provided by another of the plurality of the communication devices, and while operating in the coordinating mode, collecting and storing location determining information received from others of the plurality of communication devices;

determining that one of the plurality of communication devices has changed location by comparing location determining information collected during different instances of operation in the coordinating mode; and

updating location determining information for selected devices of the plurality of communication devices device based on location determining information collected by the particular device for at least two instances of operation in the coordinating mode.

11. The method of claim 10, further comprising the step of determining that the particular device has changed location relative to others of the plurality of communication devices when a comparison of relative location determining information collected during two different instances of operation in the coordinating mode yield differences for a substantial number of the plurality of communication devices.

12. The method of claim 10, wherein the relative location information comprises signal quality information for communications between the particular communication device and another of the plurality of communication devices.

13. A method operating a plurality of communication devices, the method comprising the steps of, at a particular device selected from the plurality of communication devices:

operating in a coordinating role for communication activity for others of the plurality of communication devices during a first period of time;

receiving a first communication from each of the other devices of the plurality of communication devices;

recording signal quality information pertaining to each of the first communication received;

operating in a role other than a coordinating role for a second period of time subsequent to the first period of time;

operating in a coordinating role for communication activity for others of the plurality of communication devices during a third period of time;

receiving a second communication from each of the other devices of the plurality of communication devices;

comparing the signal quality information for the second communication to that of the corresponding first communication for each of the second communication received;

determining that a particular device has a change in location when the signal quality information for the corresponding first communication is significantly different from that of the second communication; and

transmitting location determining information for the particular device.

14. A method of operating a plurality of communication devices, the method comprising the steps of:

at a particular device selected from the plurality of communication devices;

performing a coordinating role for communication activity among the plurality of communication devices during a first time period;

collecting and storing location determining information regarding others of the plurality of communication devices during the first time period;

suspending the coordinating role for the duration of a second time period subsequent to the first time period;

communicating with the other communication device having the coordinating role during the second time period;

resuming the coordinating role during a third time period subsequent to the second time period;

collecting location determining information regarding others of the plurality of communication devices during the third time period;

comparing location determining information collected by the particular device during the first and third time periods;

detecting that the particular device has changed location relative to others of the plurality of communication devices when the location determining information collected during the third period for a substantial number of the plurality of communication devices is different from that collected during the first time period; and

updating location information for the particular device in response to a detected change in location.

15. A method of operation of a plurality of communication devices of an asynchronous network, each of the plurality of communication devices being capable of operating in any one of a mediation communication mode for coordinating communication activity among others of the plurality of communication devices, a normal communication mode for non-coordinating communication activity, and a sleep mode for no communication activity, the method comprising the steps of:

randomly selecting the mediation communication mode for each of the plurality of communication devices;

at each of the plurality of communication devices, storing a compilation of location determining information based on communication received during each instance of operation in the mediation communication mode;

detecting changes in relative location among the plurality of the communication devices by examining changes in location determining information collected by each of the plurality of communication devices during instance of operation in the mediation communication mode; and

updating relative location information for at least some of the plurality of communication devices based on detected changes.

16. An asynchronous communications network, comprising:

a plurality of communications devices each having a plurality of communication cycles and each operable to mediate communications between the plurality of communication devices during a mediation communication period in a mediation mode and each not operable to mediate communications between the plurality of communication devices in a normal operating mode, wherein each communication cycle of the plurality of communication cycles comprises a mediation communication period during the mediation mode and a plurality of normal communication periods and a plurality of sleep periods during the normal operating mode, wherein upon entering the mediation mode, each communication device of the plurality of communication devices randomly sets a duration of a first communication cycle of the plurality of communication cycles of the communication device and collects and stores location determining information based on communication with others of the plurality of communication devices;

a processor node that receives the location determining information from the each of the plurality of communication devices and updates relative location information for the plurality of communication devices.