Communication system having multiple base stations and multiple mobile units

• US 5,212,804 A
• Filed: 10/07/1991
• Issued: 05/18/1993
• Est. Priority Date: 08/02/1990
• Status: Expired due to Term

• Current Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Original Assignee: GTE Airfone Incorporated (GOGO Incorporated)
• Inventors: Choate, Bernard K.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Pham, Chi H.
• Application Number:
  US07/772,507
• Time in Patent Office: 589 Days
• Field of Search: 455/33.1, 455/33.4, 455/34.1, 455/34.2, 455/54.1, 455/54.2, 455/56.1, 455/62, 370/95.1, 379/59, 379/60, 379/63
• US Class Current: 455/431
• CPC Class Codes: H04B 7/185 Space-based or airborne stations; Stations for satellite systemsH04B7/204 takes precedence
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185
• CPC Class Codes: Y10S 706/917 Communication

Abstract

An air-to-ground communications system is described for controlling multiple two way radiotelephone conversations between a large number of aircraft (53) and a network of base stations (51) that are capable of being interconnected to landline telephone networks (54, 116). Plural base station controllers (90) of the system, each dedicated to control one base station (51), are in turn controlled by a single central processor (52). Means are provided for matching each aircraft with an optimal base station to afford it the strongest available communication signals, and for dynamically allocating communication channels between the base stations. The central processor (52) is designed to manage the system by recording and recognizing usage patterns (525-530) and allocating channels to most efficiently use the available radio spectrum among all the aircraft (517, 519).

Claims

1. A method for managing radio frequency communications between one or more mobile units and one or more base stations, said method comprising the steps of:

making a pilot channel and a predetermined number of communication channels available at each of said base stations;

broadcasting, from each of said base stations, pilot signals over said pilot channels;

receiving, at one of said mobile units, at least one of said broadcast pilot signals;

processing, at said one mobile unit, said received pilot signal to determine whether communication channels are available for use by said one mobile unit;

processing, at said one mobile unit, said received pilot signal to determine whether communication channels associated with said base station from which said received pilot signal was broadcast are reserved for use by other ones of said mobile units and;

refraining, at said one mobile unit, from utilizing said reserved communication channels.

2. A method for managing radio frequency communications between one or more mobile units and a plurality of geographically dispersed base stations, comprising the steps of:

dividing a predetermined frequency spectrum among said base stations so that a channel is available for use at first and second ones of said base stations;

refraining from making said channel available for use at a third one of said base stations;

establishing one or more communication links between one or more mobile units and said first and second base stations using said channel, wherein said establishing step utilizes additional channels within said frequency spectrum and selects among said channel and said additional channels in response to the altitude of said mobile unit;

terminating said one or more communication links upon completion thereof;

receiving, at said first, second, and third base stations, first, second, and third availability communications, respectively, said first and second availability communications instructing the making of said channel unavailable for use and said third availability communication instructing the making of said channel available for use; and

readjusting the availability of said channel among said first, second, and third base stations in accordance with said availability communications.

3. A method for managing radio frequency communications between one or more mobile units and a plurality of geographically dispersed base stations, comprising the steps of:

dividing a predetermined frequency spectrum among said base stations so that a channel is available for use at first and second ones of said base stations;

refraining from making said channel available for use at a third one of said base stations;

establishing one or more communication links between one or more mobile units and said first and second base stations using said channel;

terminating said one or more communication links upon completion thereof;

receiving, at said first, second, and third base stations, first, second, and third availability communications, respectively, said first and second availability communications instructing the making of said channel unavailable for use and said third availability communication instructing the making of said channel available for use;

readjusting the availability of said channel among said first, second and third base stations in accordance with said availability communications;

recognizing an interruption in a communication link between one or more of said plurality of base stations and a central processor;

restricting communications between said one or more mobile units and said affected base stations to the frequency spectrum available to said affected base stations at the time of said interruption;

attempting to re-establish communications between an affected base station and said central processor;

sensing a state of resumed communications between said affected base station and said central processor; and

removing restrictions placed on communications between the one or more mobile units and the affected base stations.

4. A method for managing radio frequency communications between one or more mobile units and a plurality of geographically dispersed base stations, comprising the steps of:

dividing a predetermined frequency spectrum among said base stations so that a channel is available for use at first and second ones of said base stations;

refraining from making said channel available for use at a third one of said base stations;

establishing one or more communication links between one or more mobile units and said first and second base stations using said channel;

terminating said one or more communication links upon completion thereof;

receiving, at said first, second, and third base stations, first, second, and third availability communications, respectively, said first and second availability communications instructing the making of said channel unavailable for use and said third availability communication instructing the making of said channel available for use; and

readjusting the availability of said channel among said first, second, and third base stations in accordance with said availability communications, said readjusting step comprising the steps of;

periodically computing a scheme for dividing availability of said frequency spectrum among said plurality of base stations during an upcoming period;

reallocating availability of said frequency spectrum among said plurality of base stations according to said scheme;

receiving requests for making additional frequency spectrum available from said plurality of base stations;

determining whether a solution for solving said requests for additional frequency spectrum is known; and

applying a known solution, thereby satisfying said requests for additional frequency spectrum.