Method of anticipating a communication unit's location in a networked radio communications system

• US 5,408,683 A
• Filed: 07/18/1991
• Issued: 04/18/1995
• Est. Priority Date: 07/18/1991
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Sasuta, Michael D., Ablay, Sewim F.
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US07/732,539
• Time in Patent Office: 1,370 Days
• Field of Search: 455/33.1, 455/33.2, 455/33.3, 455/33.4, 455/54.1, 455/54.2, 455/56.1, 379/59, 379/60
• US Class Current: 455/433
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 68/04 multi-step notification using statistical or historical mobility data
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

A method of tracking subscribers (201, 203) in a networked radio communications system (100, 200). The subscribers (201,203) are able to roam among a plurality of coverage areas (104-106) which are serviced by a plurality of transmitters (107-109). The transmitters (107-109) are coupled to a central processor (CP, 110), which accesses a memory device (112) for storing subscriber records and site records. Subscriber records include location information for each of the subscribers, while the site records include a logical representation of geographical relationships between the coverage areas. The method relies on the subscriber to send an inbound message (330) which includes its current location. Further, the CP (110) records a message time for the inbound message, producing a timestamped location, then updates (405) a corresponding portion of the subscriber record with the timestamped location.

Claims

1. In a networked radio communications system that includes a plurality of subscribers and a plurality of transmitter sites that service a plurality of coverage areas, each subscriber being able to roam between the plurality of coverage areas, each of the transmitter sites providing at least one of a plurality of transmitters that are each coupled to a central processor which accesses a memory device holding subscriber records and site records, the subscriber records including, inter alia, a location for each of the subscribers, the site records including a logical representation of geographical relationships among the plurality of coverage areas, a method of delivering an outbound message using reduced control channel signaling, the method comprising the steps of:

at the subscriber,

determining a current location, within a current coverage area;

sending an inbound message which includes at least said current location;

at the central processor,

recording said current location and a message time for said inbound message to produce a timestamped location;

updating at least a portion of a corresponding subscriber record with said timestamped location;

determining, based on said corresponding subscriber record and a site record for said current coverage area,

at least one coverage area in which the subscriber is most likely located, to produce at least one anticipated coverage area;

calculating a difference between the present time and a previous registration time, to produce an elapsed time;

determining, based in part on said timestamped location, a probable maximum time in which the subscriber would be outside at least said current coverage area;

comparing said probable maximum time with said elapsed time and delivering, responsive to the step of comparing, said outbound message to the subscriber.

2. In a networked radio communications system that includes a plurality of subscribers and a plurality of transmitter sites which service a plurality of coverage areas, each subscriber being able to roam between the plurality of coverage areas, each of the transmitter sites providing at least one of a plurality of transmitters that are each coupled to a central processor which accesses a memory device holding subscriber records and site records, the subscriber records including, inter alia, a location for each of the subscribers, the site records including a logical representation of geographical relationships among the plurality of coverage areas, a method of identifying at least one of the plurality of transmitter sites for delivery of an outbound message to a subscriber, the method comprising the steps of:

at the subscriber,

determining a current location, within a current coverage area;

sending an inbound message which at least includes said current location; and

appending to said inbound message a current speed and direction of the subscriber, to produce a directional vector;

at the central processor,

recording said current location and a message time for said inbound message to produce a timestamped location;

updating at least a portion of a corresponding subscriber record with said timestamped location;

receiving the outbound message for delivery to the subscriber;

determining, based on said timestamped location and a site record for said current coverage area, at least one coverage area in which the subscriber is most likely located, to produce at least one anticipated coverage area;

calculating a difference between the present time and a previous registration time, to produce an elapsed time;

determining, based in part on said timestamped location and said directional vector, a probable maximum time in which the subscriber would be outside at least said current coverage area;

comparing said probable maximum time with said elapsed time and delivering, resonsive to the step of comparing, said outbound message to the subscriber.

3. A method in accordance with claim 2, further comprising the step of, at the central processor, routing said outbound message to at least one transmitter serving said at least one transmitter site.

4. In a networked radio communications system that includes a plurality of subscribers and a plurality of transmitter sites which service a plurality of coverage areas, each subscriber being able to roam between the plurality of coverage areas, each of the transmitter sites providing at least one of a plurality of transmitters that are each coupled to a central processor which accesses a memory device holding subscriber records and site records, the subscriber records including, inter alia, a location for each of the subscribers, the site records including a logical representation of geographical relationships among the plurality of coverage areas, a method of identifying at least one of the plurality of transmitter sites for delivery of an outbound message to a subscriber, the method comprising the steps of:

at the subscriber,

determining a current location, within a current coverage area;

sending, at an origination time, inbound messages which at least include said current location at said origination time; and

appending to said inbound message a current speed and direction of the subscriber, to produce an actual directional vector;

at the central processor,

recording said current location and a message time for said inbound messages to produce at least one timestamped location;

updating at least a portion of a corresponding subscriber record with said at least one timestamped location;

receiving the outbound message for delivery to the subscriber;

determining, based on said at least one timestamped location and a site record for said current coverage area, at least one coverage area in which the subscriber is most likely located, to produce at least one anticipated coverage area;

calculating a difference between the present time and a previous registration time, to produce an elapsed time;

determining, based in part on said at least one timestamped location and said actual directional vector, a probable maximum time in which the subscriber would be outside at least said current coverage area;

comparing said probable maximum time with said elapsed time and delivering, responsive to the step of comparing, said outbound message to the subscriber.

5. A method in accordance with claim 4, further comprising the step of, at the central processor, updating at least a portion of the corresponding subscriber record with said actual directional vector.

6. A method in accordance with claim 4, further comprising the step of, at the central processor, calculating, based in part on at least two timestamped locations, an estimated directional vector, wherein said at least two timestamped locations include said at least one timestamped location.

7. A method in accordance with claim 6, further comprising the step of, at the central processor, updating at least a portion of the corresponding subscriber record with said estimated directional vector.

8. A method in accordance with claim 7, wherein said step of determining at least one probable delivery site further comprises the steps of:

calculating a difference between the present time and a previous registration time, to produce an elapsed time;

determining, based in part on said timestamped location and said estimated directional vector, a probable maximum time in which the subscriber would be outside at least said current coverage area; and

comparing said probable maximum time with said elapsed time.

9. A method, for use by a subscriber in a networked radio communications system that serves a plurality of coverage areas, to reduce control channel traffic on the networked radio communications system, the plurality of coverage areas being serviced by a central processor, the method comprising the steps of:

determining a current location, within a current coverage area;

recording trend data for the subscriber to produce recorded trend data;

establishing, based at least in part on said current location and said recorded trend data, directional vectors to produce established directional vectors;

storing at least two of said established directional vectors to produce at least two stored directional vectors;

comparing said at least two stored directional vectors to detect a difference between said at least two stored directional vectors; and

when the difference detected exceeds a predetermined threshold, sending an inbound message to the central processor, wherein said inbound message includes at least said current location.

10. A method in accordance with claim 9, wherein said step of establishing further comprises the step of determining current speed and direction of the subscriber.

11. A method in accordance with claim 9, wherein said step of establishing further comprises the step of using historical location data to calculate said directional vectors.

12. A method in accordance with claim 9, wherein said step of sending an inbound message further comprises the step of sending at least one of said directional vectors.