Micro cell architecture for mobile user tracking communication system

• US 6,388,615 B1
• Filed: 06/06/2000
• Issued: 05/14/2002
• Est. Priority Date: 06/06/2000
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Inventors: Chang, Donald C. D., Cha, Alan, Chang, Ming, Feria, Ying, Yung, Kar W., Hagen, Frank A., Wang, Weizheng
• Primary Examiner(s): Phan, Dao
• Application Number:
  US09/587,758
• Time in Patent Office: 707 Days
• Field of Search: 342/154, 342/157, 342/354, 342/368, 342/357.06, 455/456
• US Class Current: 342/368
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04B 7/18504 Aircraft used as relay or high altitude atmospheric platform

Abstract

A system and method for tracking a user. The system is adapted for use in a wireless communication system and creates a plurality of beams within a coverage area. A first beam is directed at a user in a first microcell and a number of additional beams illuminate microcells immediately adjacent the first microcell. The system is equipped with a mechanism for detecting movement of the user from the first microcell to one of the immediately adjacent microcells. On the detection of movement of the user, the system redirects the first beam from the first microcell to a second microcell, the second microcell being one of the adjacent microcells. In the illustrative embodiment, the system is implemented in a stratospheric platform based communication system including a hub adapted to communicate with a stratospheric platform. A transceiver and a phased array antenna are disposed on the platform to communicate with the hub and with the user. A second antenna is provided on the platform to communicate with the hub. Beamforming and direction are implemented on the hub and communicated to the platform. The user'"'"'s position is detected with a global positioning system receiver, by measuring the strength of a signal received from the user, or by other suitable means. On detection of user movement from the first microcell, the beamforming system redirects the beam to follow the user into a second microcell. Additional beams around the user'"'"'s microcell are illuminated to facilitate detection of the users movement.

Claims

1. A user tracking system for a wireless communication system comprising:

first means for creating a plurality of beams within a coverage area, a first beam being directed at a user at a first microcell and a number of additional beams illuminating microcells immediately adjacent said first microcell;

second means for detecting movement of said user from said first microcell to one of said immediately adjacent microcells; and

third means for redirecting, on the detection of said movement, said first beam from said first microcell to a second microcell, said second microcell being one of said adjacent microcells.

2. The system of claim 1 wherein said first means is a stratospheric platform based communication system including a hub adapted to communicate with a stratospheric platform.

3. The system of claim 2 further including a transceiver and a phased array antenna disposed on said platform.

4. The system of claim 3 further including means disposed at said hub for creating a beamforming signal for use by said phased array antenna.

5. The system of claim 4 wherein said second means is a global positioning system receiver.

6. The system of claim 4 wherein said second means includes means for measuring the strength of a signal received from said user.

7. The system of claim 6 wherein said hub includes said third means.

8. The system of claim 7 wherein said third means includes means responsive to said second means for causing said means for creating a beamforming signal to redirect said first beam.

9. The system of claim 2 wherein said third means includes means for redirecting said additional beams to illuminate microcells immediately adjacent said second microcell on the detection of movement of said user from said first microcell to one of said adjacent microcells.

10. A user tracking system for a wireless stratospheric based communication system comprising:

first means for creating a plurality of beams within a coverage area, a first beam being directed at a user in a first microcell and a number of additional beams illuminating microcells immediately adjacent said first microcell, said first means including a hub adapted to communicate with a stratospheric platform, said platform having a transceiver and a phased array antenna, said hub having means for creating a beamforming signal for use by said phased array antenna;

second means for detecting movement of said user from said first microcell to one of said immediately adjacent microcells; and

third means for redirecting, on the detection of said movement, said first beam from said first microcell to a second microcell, said second microcell being one of said adjacent microcells, said third means including means responsive to said second means for causing said means for creating a beamforming signal to redirect said first beam and means for redirecting said additional beams to illuminate microcells immediately adjacent said second microcell on the detection of movement of said user from said first microcell to one of said adjacent microcells.

11. The system of claim 10 wherein said second means is a global positioning system receiver.

12. The system of claim 10 wherein said second means includes means for measuring the strength of a signal received from said user.

13. A method for tracking a user in a wireless communication system comprising the steps of:

creating a plurality of beams within a coverage area, a first beam being directed at a user at a first microcell and a number of additional beams illuminating microcells immediately adjacent said first microcell;

detecting movement of said user from said first microcell to one of said immediately adjacent microcells; and

redirecting, on the detection of said movement, said first beam from said first microcell to a second microcell, said second microcell being one of said adjacent microcells.