Patent ID: 6411609
Filing Date: 2002-06-25
Classification: H04B

Abstract:
In a communication satellite that uses time division duplex (TDD) techniques to communicate with remote subscribers, a method for transitioning between a first TDD frame structure and a second TDD frame structure, said first TDD frame structure including a predetermined number of time slots that are each either a transmit type time slot or a receive type time slot, said second TDD frame structure being synchronous with said first TDD frame structure and including an equal number of time slots to said first TDD frame structure, said time slots in said second TDD frame structure each being either a transmit type time slot or a receive type time slot, wherein transmit type time slots in said first TDD frame structure correspond in time to receive type time slots in said second TDD frame structure and receive type time slots in said first TDD frame structure correspond in time to transmit type time slots in said second TDD frame structure, said method comprising the steps of:providing a first satellite orbiting a primary body in an inclined orbital plane, said first satellite communicating with a plurality of subscribers using a plurality of time slots that follow the first TDD frame structure; determining that said first satellite has entered a transition region in said inclined orbital plane; deactivating, after said step of determining, a subset of time slots in said plurality of time slots so that no communication is performed during said subset of time slots; activating at least one deactivated time slot as a time slot type that is opposite to a time slot type associated with said at least one deactivated time slot previous to said deactivating step; and repeating said steps of deactivating and activating until said plurality of time slots follow the second TDD frame structure.