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1. WO1996003814 - MULTI-BEAM TDMA SATELLITE MOBILE COMMUNICATIONS SYSTEM

Publication Number WO/1996/003814
Publication Date 08.02.1996
International Application No. PCT/GB1995/001103
International Filing Date 16.05.1995
Chapter 2 Demand Filed 20.02.1996
IPC
H04B 7/185 2006.01
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
7Radio transmission systems, i.e. using radiation field
14Relay systems
15Active relay systems
185Space-based or airborne stations
H04B 7/204 2006.01
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
7Radio transmission systems, i.e. using radiation field
14Relay systems
15Active relay systems
204Multiple access
CPC
H04B 7/18534
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
7Radio transmission systems, i.e. using radiation field
14Relay systems
15Active relay systems
185Space-based or airborne stations; ; Stations for satellite systems
1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
18532Arrangements for managing transmission, i.e. for transporting data or a signalling message
18534for enhancing link reliablility, e.g. satellites diversity
H04B 7/18539
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
7Radio transmission systems, i.e. using radiation field
14Relay systems
15Active relay systems
185Space-based or airborne stations; ; Stations for satellite systems
1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
18539Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
H04B 7/1855
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
7Radio transmission systems, i.e. using radiation field
14Relay systems
15Active relay systems
185Space-based or airborne stations; ; Stations for satellite systems
1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
18545Arrangements for managing station mobility, i.e. for station registration or localisation
18547for geolocalisation of a station
1855using a telephonic control signal, e.g. propagation delay variation, Doppler frequency variation, power variation, beam identification
H04B 7/2041
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
7Radio transmission systems, i.e. using radiation field
14Relay systems
15Active relay systems
204Multiple access
2041Spot beam multiple access
Applicants
  • INTERNATIONAL MOBILE SATELLITE ORGANIZATION [--/GB]; 99 City Road London ECIY IAX, GB (AllExceptUS)
  • HART, Nicholas [AU/AU]; GB (UsOnly)
  • BJÖRNSTROM, Gunnar [SE/GB]; GB (UsOnly)
Inventors
  • HART, Nicholas; GB
  • BJÖRNSTROM, Gunnar; GB
Agents
  • R G C JENKINS & CO.; 26 Caxton Street London SW1H 0RJ, GB
Priority Data
9414829.322.07.1994GB
Publication Language English (EN)
Filing Language English (EN)
Designated States
Title
(EN) MULTI-BEAM TDMA SATELLITE MOBILE COMMUNICATIONS SYSTEM
(FR) SYSTEME DE TELECOMMUNICATIONS MOBILE PAR SATELLITE AMRT MULTIFAISCEAU
Abstract
(EN)
An earth station (8) receives a return signal (3) via more than one satellite link (4a, 4b) from a mobile terminal (2) using TDMA. The earth station (8) selects one or more of the satellite links (4a) for transmitting a forward signal (15) on the basis of the quality of signal (3; 15) received via each link. The earth section (8) allocates frequency channels to the mobile terminals (2) according to their location on the surface of the earth, so that the propagation time to and from those mobile terminals (2) which share the same frequency channel is approximately the same. The satellite (4a; 4b) includes an antenna which generates an array of beams which are individually pointed to fixed regions of the earth, until the elevation of the satellite (4a; 4b) relative to a fixed region falls below a minimum value, in which case the corresponding beam is redirected to a new area, while the other beams remain pointed at the corresponding fixed areas. In this way, beam-to-beam handover is reduced, while maintaining the boresight of the antenna pointing at the nadir.
(FR)
Une station de terre (8) reçoit un signal de retour (3) par l'intermédiaire de plus d'une liaison satellite (4a, 4b) en provenance d'un terminal mobile (2) en utilisant l'accès multiple à répartition dans le temps (AMRT). La station de terre (8) sélectionne une ou plusieurs des liaisons satellite (4a) pour transmettre un signal d'avance (15) sur la base de la qualité du signal (3; 15) reçu par l'intermédiaire de chaque liaison. La station de terre (8) attribue des canaux de fréquence aux terminaux mobiles (2) en fonction de leur position à la surface de la terre, pour que le temps de propagation à destination et en provenance de ces terminaux mobiles (2) qui partagent le même canal de fréquence soit approximativement le même. Le satellite (4a; 4b) comprend une antenne qui produit un groupe de faisceaux, lesquels sont pointés individuellement sur des régions fixes de la terre, jusqu'à ce que la hauteur d'élévation du satellite (4a; 4b) par rapport à une région fixe tombe au-dessous d'une valeur minimum. Dans ce cas, le faisceau est redirigé sur une nouvelle zone, pendant que les autres faisceaux restent pointés sur les zones fixes correspondantes. Ainsi, on réduit la commutation de faisceau à faisceau, tout en maintenant l'axe de pointage de l'antenne orienté au nadir.
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