Cellular telephone system that uses position of a mobile unit to make call management decisions

• US 5,235,633 A
• Filed: 12/26/1991
• Issued: 08/10/1993
• Est. Priority Date: 12/26/1991
• Status: Expired

• Current Assignee: EMSAT Advanced Geo-Location Technology LLC
• Original Assignee: Sygnet Communications, Inc. (AT&T, Inc.)
• Inventors: Pauley, Gregory T., Duffy, Timothy J., Dennison, Everett, Jones, Scott L., Nass, Edwin L., Shale, Deborah J.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Bost, Dwayne D.
• Application Number:
  US07/813,494
• Time in Patent Office: 593 Days
• Field of Search: 379/58-60, 455/12.1-13.2, 455/33.1, 455/33.2, 455/54.1, 342/190, 342/191, 342/352, 342/357, 342/450, 342/451, 342/452, 342/454, 342/456, 342/457, 342/458, 342/464
• US Class Current: 455/456.3
• CPC Class Codes: H04B 7/18541 for handover of resources
• CPC Class Codes: H04B 7/18552 using a telephonic control signal and a second ranging satellite determining absolute distances from a plurality of spaced points of known location G01S5/14
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/322 by location data
• CPC Class Codes: H04W 4/02 Services making use of location information

Abstract

A cellular telephone system includes a plurality of cell sites and a mobile telephone switching office. Call management, including selection of a cell site most appropriate for a call associated with a mobile unit, are made based on the geographic location of the mobile unit as opposed to the strength of the signal associated with the call. The geographic location of the mobile unit is precisely determined using a NAVSTAR global positioning system, or its equivalent. Each mobile unit includes a GPS receiver that receives information from a geostationary satellite to determine the precise location of the mobile unit. This position information is relayed to the cell site initially managing the mobile unit, and the mobile unit is handed off to a cell site that is most appropriate for the call. Initial selection of an entrance cell site is made based on signal strength, but further call management decisions are made based on location of the mobile unit.

Claims

1. A cellular communications system that includes one or more cell sites and an MTSO, said system comprising:

A) locating means in a mobile unit of a cellular communications system for determining the exact geographic location of the mobile unit, said locating means including means using a satellite communication system for establishing an exact geographic location of said mobile unit and for emitting a position signal of said exact geographic location;

B) means in the MTSO for receiving the position signal transmitted by the mobile unit and using that position signal to establish the exact geographic location of the mobile unit vis evis cell sites in the cellular communications network; and

C) data storage and comparison means in the MTSO storing cell site location data giving a geographic location for each of the cell sites in the cellular communications network and effecting a comparison between said position signal and said cell site location data and selecting a chosen cell site for use by said mobile unit based on said comparison and establishing communication between said mobile unit and said chosen cell site based on the exact geographic location of the mobile unit.

2. The cellular communication system defined in claim 1 wherein said locating means includes a means for communicating with a satellite.

3. The cellular communication system defined in claim 2 wherein said means in the MTSO for determining the geographic location of a cell site includes a look-up table.

4. The cellular communication system defined in claim 3 wherein said locating means includes a GPS.

5. The cellular communication system defined in claim 3 wherein said locating means includes a GPS receiver connected to logic circuitry in said mobile unit.

6. The cellular communications system defined in claim 5 wherein said mobile unit includes a duplexer.

7. The cellular communications system defined in claim 6 wherein said mobile unit includes a GPS receiver located between said duplexer and said logic circuitry.

8. The cellular communications system defined in claim 7 further including means for placing location data on voice and data communication signals.

9. The cellular communications system defined in claim 8 further including means for making call management decisions based on signal strength.

10. A cellular communications system that includes one or more cell sites and an MTSO, said system comprising:

A) locating means in a mobile unit in a cellular communications system for determining the exact geographic location of the mobile unit; and

B) management means in the MTSO for making call management decisions based on the geographic location of the mobile unit, said management means including means for storing the geographic location of each cell site in the cellular communications system and for comparing the exact geographic location of the mobile unit to the geographic location of each cell site and for selecting a cell site for use by the mobile unit based on such

11. A method of making call management decisions in a cellular telephone system having a plurality of cell sites at various geographic locations and an MTSO in which the geographic location of each cell site in the cellular telephone system has been stored, the method comprising steps of:

A) establishing an exact geographic location for a mobile unit;

B) matching the geographic location of the mobile unit to a cell site location, and selecting a cell site based on such matching; and

C) using the selected cell site geographic matched to the mobile unit to handle calls associated with the mobile unit.

12. The method defined in claim 11 further including a step of handing off the mobile unit to a second cell site based on the position of the mobile unit.

13. The method defined in claim 12 further including a step of continuously monitoring the position of the mobile unit as the mobile unit moves, and handing off the mobile unit to various cell sites based on the instantaneous location of the mobile unit.

14. The method defined in claim 13 further including assessing message unit charges to a call made from the mobile unit.

15. The method defined in claim 13 wherein said call management decisions include deciding which cell site will initially handle a call to or from a mobile unit.