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

• US 5,946,611 A
• Filed: 06/21/1996
• Issued: 08/31/1999
• Est. Priority Date: 12/26/1991
• Status: Expired due to Term

• Current Assignee: EMSAT Advanced Geo-Location Technology LLC
• Original Assignee: Sycord Limited Partnership
• Inventors: Pauley, Gregory T., Nass, Edwin L., Shale, Deborah J., Duffy, Timothy J., Dennison, Everett, Jones, Scott L.
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Gesesse, Tilahun
• Application Number:
  US08/670,281
• Time in Patent Office: 1,166 Days
• Field of Search: 455/456, 455/404, 455/12.1, 455/457, 455/521, 455/440, 455/445
• US Class Current: 455/404.2
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• 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 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

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 method of making emergency call decisions in a cellular telephone system having a plurality of cell sites at various geographic locations comprising:

A) providing a mobile unit which can be located at various and changeable geographic locations;

B) using the mobile unit to place a call requesting emergency service via a cellular telephone system;

C) determining the exact geographic location of the mobile unit placing the call requesting emergency service;

D) storing geographic data associated with the cellular telephone system and which are required to complete the call requesting emergency service;

E) comparing the exact geographic location of the mobile unit placing the call requesting emergency service to the stored geographic data; and

F) automatically routing the mobile unit call requesting emergency service to an emergency service based on the comparison regardless of cell site location.

2. The method defined in claim 1 wherein the step of determining the exact geographic location of the mobile unit includes using over-the-air communications.

3. The method defined in claim 1 wherein the step of storing geographic data associated with the cellular telephone system includes placing those geographic data on a look-up table.

4. The method defined in claim 3 wherein the step of comparing the exact geographic location of the mobile unit placing the call requesting emergency service to the stored geographic data includes using the look-up table for said comparing step.

5. The method defined in claim 1 further including a step of communicating the exact geographic location of the mobile unit placing the call requesting emergency service to the emergency service.