Satellite communications transfer method

Abstract

Method for transferring communications by satellite The present invention relates to a method (30) for transferring communications by satellite comprising the following steps: - by each terminal of a plurality (32), determining (38) and transmitting (40) positioning and mobility information to a moving source satellite participating in a current satellite communication with said terminal;- by each scrolling source satellite (34), from said positioning and mobility information(s) received, determination (42) and transmission (44) of at least one satellite communications transfer vector, each transfer vector being transmitted to a scrolling target satellite, and configured to inform it of all the mobile user terminals whose satellite communication continuity, identified by a session identifier also indicated within said vector, is to be taken over at the next change of satellite coverage sector, according to said scrolling. Figure for the abstract: Figure 2;

Claims

Claims

1. Method (30) for transferring satellite communications implemented within a satellite communications system, said satellite communications system comprising at least a plurality (32) of mobile user terminals on the ground and the satellite communication resources of a constellation of satellites moving according to a predetermined scrolling with a constant speed of movement, said method comprising at least the following steps, implemented cyclically at each exchange cycle between a mobile user terminal and a satellite of said constellation of moving satellites, said cycle taking into account said predetermined scrolling: - by each mobile user terminal of said plurality, determination (38) of positioning and mobility information,and transmission (40) of said positioning and mobility information to a scrolling source satellite participating in a current satellite communication with said mobile user terminal; - by each scrolling source satellite (34), from said positioning and mobility information(s) received from said mobile user terminal(s) of which said source satellite has the current satellite communication management, determination (42) and transmission (44) of at least one satellite communication transfer vector, each satellite communication transfer vector being transmitted to a scrolling target satellite, and configured to inform it of all the mobile user terminals whose satellite communication continuity, identified by a session identifier also indicated within said vector, is to be taken over at the next change of satellite coverage sector, according to said scrolling.,

2. A method of transferring communication by satellite according to claim 1, wherein said step of determining positioning and mobility information comprises determining at least three elements forming said positioning and mobility information corresponding to: - the speed of movement of said mobile user terminal; - the direction of movement of said mobile user terminal; - the current position of said mobile user terminal.

3. A satellite communication handover method according to claim 1 or 2, further comprising a step, performed by each traveling target satellite, of receiving said satellite communication handover vector and generating (46) and transmitting (48) an acknowledgment message of said satellite communication handover vector to said source satellite having transmitted said satellite communication handover vector.

4. A satellite communication handover method according to claim 3, further comprising the following steps, implemented by each scrolling source satellite: - receiving each handover vector acknowledgment message transmitted by each target satellite; - generating (50) a satellite communication resource control message configured to inform each mobile user terminal, of which said source satellite has the current satellite communication management, of the target satellite responsible for taking over the current satellite communication at the next change of satellite coverage sector, according to said scrolling, and transmitting (52) said message to each mobile user terminal, of which said source satellite has the current satellite communication management.

5. A method of satellite communication handover according to claim 4, further comprising the following steps, performed by each mobile user terminal of said plurality: - receiving said satellite communication resource control message; - estimating (54) the time remaining until said handover of support for the current satellite communication by said target satellite indicated within said satellite communication resource control message; - generating (56), and transmitting (58) to said source satellite having support for the current satellite communication, a message acknowledging receipt of said satellite communication resource control message; satellite communication including said remaining time before transfer estimated during said estimation; - preparation (60) of the position of its antenna system to point said target satellite at the end of said estimated remaining time.

6. A method of transferring satellite communication according to claim 5, wherein said estimation uses the reference frame of the ephemeris of the scrolling of said target satellite.

7. A method (10) of satellite communication handover according to claim 5 or 6, further comprising the following steps, performed by each scrolling source satellite: - receiving each acknowledgment message comprising said estimated remaining time before handover transmitted by each mobile user terminal, including said source satellite in current satellite communication management, - updating (62) each satellite communication handover vector with an indication of handover times obtained from a message transmission time and said estimated remaining times before handover and associated with each mobile user terminal of said set of mobile user terminals indicated within each handover vector, and transmitting (64) each updated satellite communication handover vector to the corresponding scrolling target satellite.

8. A method (10) for transferring satellite communications according to claim 7, further comprising a step (66), implemented by each mobile user terminal, after expiration of said remaining time before transfer, of generating and transmitting, to said target satellite, a message confirming said transfer of satellite communications.

9. A computer program comprising software instructions which, when executed by a computer, implement a satellite communications transfer method according to any one of the preceding claims.

10. Satellite communication system (10) comprising at least a plurality (22) of mobile user terminals on the ground and the satellite communication resources of a constellation of satellites (12b 122, 123) moving according to a predetermined movement pattern with a constant speed of movement D, said satellite communication system (10) being configured to implement implements the satellite communication transfer method according to any one of the preceding claims 1 to 8.

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