Communication system having multiple base stations and multiple mobile units

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.

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.

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.