Spot beam selection in a mobile satellite communication system

• US 6,233,451 B1
• Filed: 07/13/1998
• Issued: 05/15/2001
• Est. Priority Date: 07/14/1997
• Status: Expired due to Term

• Current Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Original Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Inventors: Gao, Zhengping, Demers, Stephanie, Noerpel, Anthony, Parr, Michael, Joshi, Chandra
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): CHOW, CHARLES CHIANG
• Application Number:
  US09/115,096
• Time in Patent Office: 1,037 Days
• Field of Search: 455/427, 455/429, 455/430, 455/428, 455/507, 455/517
• US Class Current: 455/427
• CPC Class Codes: H04B 7/18517 Transmission equipment in earth stations
• CPC Class Codes: H04B 7/18539 Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04B 7/18558 Arrangements for managing communications, i.e. for setting up, maintaining or releasing a call between stations
• CPC Class Codes: H04B 7/18567 Arrangements for providing additional services to the basic mobile satellite telephony service
• CPC Class Codes: H04B 7/18571 for satellites; for fixed or mobile stations
• CPC Class Codes: H04B 7/1858 Arrangements for data transmission on the physical system, i.e. for data bit transmission between network components
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access
• CPC Class Codes: H04B 7/19 Earth-synchronous stations
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04B 7/2125 Synchronisation
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 52/0203 in the radio access network or backbone network of wireless communication networks
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/00 Wireless channel access
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 76/25 Maintenance of established connections
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 84/06 : Airborne or Satellite Networks space-based or airborne stations H04B7/185
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

An access terminal for initiating spot beam selection in a satellite communication system, in which the access terminal includes a receiver for measuring the received signal strength (RSS) of a multiplicity of radio frequency communication spot beam links. The access terminal is further provided with a microcontroller for comparing the received signal strengths from each of the multiplicity of spot beams to initiate information communication via a communication channel of the satellite communication system. In a described embodiment, the controller of the access terminal compares seven spot beam links to determine whether to initiate information communication with one of the seven spot beams received. Additionally, a memory coupled to the controller of the access terminal is used for storing spot beam identification information including the spot beam links assigned to the access terminal via the satellite communication system. The selection procedure employed by the system and method described facilitate a rapid selection of an appropriate spot beam identified from the multiplicity of radio frequency spot beam links received at a mobile access terminal.

Claims

1. An access terminal for initiating spot beam selection in a mobile satellite communication system, the access terminal comprising:

a receiver for measuring the received signal strength (RSS) of a multiplicity of radio frequency communication spot beam links, each of said spot beam links including neighboring spot beam information pertaining to a plurality of neighboring spot beam links;

a controller for comparing the signal strengths of each of said spot beam links in view of said neighboring spot beam link information to initiate information communication via a communication channel of the satellite communication system; and

a memory coupled to said controller for storing spot beam identification information indicating spot beam links assigned to the access terminal via the satellite communication system.

2. An access terminal as recited in claim 1 wherein said receiver determines the received signal strength from a cell associated with a first spot beam and a cell associated with a second adjacent spot beam.

3. An access terminal as recited in claim 2 wherein said receiver receives broadcast signals from any broadcast channel (BCCH) and six neighboring channels.

12. The access terminal of claim 1, wherein each said spot beam is substantially stationary with respect to the earth'"'"'s surface.

15. The access terminal of claim 1, wherein said receiver communicates with at least one of a public switched telephone network and another mobile terminal via an air communication interface between a satellite and a gateway.

18. An access terminal as recited in claim 1, wherein said neighboring spot beam information includes information indicating a respective frequency and time of broadcast of each of said plurality of neighboring spot beam links.

4. A system for spot beam selection in a mobile satellite communication system, comprising:

a mobile access terminal;

a radio frequency communication space segment for transmitting communication channels via a multiplicity of spot beam links, each of said spot beam links including neighboring spot beam information pertaining to a plurality of neighboring spot beam links;

a receiver coupled to said access terminal for initiating, based on said neighboring spot beam information, multiple information communication with said space segment via one or more of said multiplicity of spot beam links; and

a memory coupled to said receiver for storing spot beam identification information, including said neighboring spot beam information, for establishing the radio frequency communication link to said receiver.

5. A system as recited in claim 4 wherein said mobile access terminal comprises a controller for comparing received signal strength (RSS) of each spot beam to initiate information communication via a communication channel of the satellite communication system.

6. A system as recited in claim 5 wherein said controller simultaneously receives broadcast carrier signals from the multiplicity of radio frequency spot beam links.

13. The system of claim 4, wherein each said spot beam is substantially stationary with respect to the earth'"'"'s surface.

16. The system of claim 4, wherein said mobile access terminal communicates with at least one of a public switched telephone network and another mobile terminal via an air communication interface between a satellite and a gateway.

19. A system as recited in claim 5, wberein said neighboring spot beam information includes information indicating a respective frequency and time of broadcast of each of said plurality of neighboring spot beam links.

7. A method of spot beam selection in a mobile satellite communications system, comprising the steps of:

initiating information communication from the access terminal via a multiplicity of spot beam links to space segment communication channels;

assigning protocol processing information to the access terminal over a radio frequency communication link for conveying multiple communication channels for communication with the access terminal, said protocol processing information including neighboring spot beam information pertaining to a plurality of neighboring spot beams; and

controlling said access terminal to select a spot beam link from said multiplicity based on said neighboring spot beam information.

8. A method as recited in claim 7 further comprising the step of receiving carrier signals from each of said multiplicity of spot beam links.

9. A method as recited in claim 8 wherein said receiving step simultaneously receives a broadcast carrier from the multiplicity of spot beam links from the space segment communication channels.

10. A method as recited in claim 8 wherein said receiving step measures the signal strength of the received carrier from the multiplicity of spot beam links from the space segment communication channel on a step by step basis to measure the spot beam signal strength.

11. A method as recited in claim 10 wherein said receiving step sequentially measures individual spot beam link signal strengths from the space segment communication channels.

14. The method of claim 7, wherein each said spot beam is substantially stationary with respect to the earth'"'"'s surface.

17. The method of claim 7, wherein said access terminal communicates with at least one of a public switched telephone network and another mobile terminal via an air communication interface between a satellite and a gateway.

20. A method as recited in claim 7, wherein said neighboring spot beam information includes information indicating a respective frequency and time of broadcast of each of said plurality of neighboring spot beam links.