Method and apparatus for handover control in a satellite based telecommunications system
First Claim
1. An apparatus for controlling mobile and base stations during satellite based telecommunications to perform scheduled handovers between first and second communications channels, said apparatus comprising:
- a mobile station including at least one transceiver for simultaneously receiving communications data over communications links in said first and second communications channels, at least one transmitter for transmitting communications data over at least one of said first and second communications channels, and an MS controller for selectively connecting a transceiver to said transmitter to transmit communications data over a communications link in at least one of said first and second communications channels; and
a base station including at least one transceiver for simultaneously transmitting communications data over first and second channels, and for receiving communications data over at least one of said first and second channels, and a BS controller for maintaining a communications link over at least one of said first and second channels, said MS and BS controllers maintaining a first communications link over said first channel via a satellite, said BS controller determining when a handover is necessary between said first and second channels, said BS controller transmitting over said first channel a scheduled handover time in response to said determination by said BS controller that a handover is necessary, said handover time representing a predetermined future point in time at which a handover will occur;
wherein said MS and BS controllers establish a second communications link in said second channel while simultaneously continuing to transmit communications data over said first communications link in said first channel, said MS and BS controllers switching to said second channel for transmitting communications data at said scheduled handover time.
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0 Petitions
Accused Products
Abstract
A method and apparatus are provided for controlling mobile and base stations (14 and 16) during satellite (12) based telecommunications to perform scheduled handovers between two communications channels (26 and 27). The base station (16) determines when a handover will be necessary. Once determined, the base station (16) generates a handover scheduling command (node #4) which includes a scheduled handover time representing a time in the future at which the handover will occur. The handover scheduling command is transmitted over the first channel to the mobile station (14). Upon receipt of the handover scheduling command, the mobile station (14) performs steps necessary to establish a second communications link over a second channel (27), prior to the scheduled handover time. At the scheduled handover time (node #21), the mobile and base stations (14 and 16) have established the second communications link on the second channel (27). To establish the second channel the mobile station calculations of the second channels frequency, timing offset and power level (node #11). By using a scheduled handover process, the mobile and base stations (14 and 16) avoid the production of interference and breaks within a conversation transmitted therebetween.
114 Citations
25 Claims
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1. An apparatus for controlling mobile and base stations during satellite based telecommunications to perform scheduled handovers between first and second communications channels, said apparatus comprising:
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a mobile station including at least one transceiver for simultaneously receiving communications data over communications links in said first and second communications channels, at least one transmitter for transmitting communications data over at least one of said first and second communications channels, and an MS controller for selectively connecting a transceiver to said transmitter to transmit communications data over a communications link in at least one of said first and second communications channels; and a base station including at least one transceiver for simultaneously transmitting communications data over first and second channels, and for receiving communications data over at least one of said first and second channels, and a BS controller for maintaining a communications link over at least one of said first and second channels, said MS and BS controllers maintaining a first communications link over said first channel via a satellite, said BS controller determining when a handover is necessary between said first and second channels, said BS controller transmitting over said first channel a scheduled handover time in response to said determination by said BS controller that a handover is necessary, said handover time representing a predetermined future point in time at which a handover will occur; wherein said MS and BS controllers establish a second communications link in said second channel while simultaneously continuing to transmit communications data over said first communications link in said first channel, said MS and BS controllers switching to said second channel for transmitting communications data at said scheduled handover time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for controlling mobile and base stations during satellite based telecommunications to perform scheduled handovers between first and second communications channels, said method comprising the steps of:
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maintaining a first communications link over a first channel between mobile and base stations via a satellite; transmitting and receiving frames of communications data over said first communications link over said first channel; determining, at the base station, when a handover is necessary between first and second channels; transmitting a scheduled handover time over said first channel, from the base station to the mobile station, in response to said determination that a handover is necessary, said scheduled handover time representing a predetermined future point in time at which a handover will occur; subsequent to transmission of said scheduled handover time, establishing a second communications link over a second channel between said mobile and base stations via a satellite while simultaneously continuing to transmit frames of communications data over said first communications link; and at said scheduled handover time, switching to said second channel and thereafter transmitting subsequent frames of communications data over said second channel. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification