Personal beam cellular communication system

• US 5,815,116 A
• Filed: 11/29/1995
• Issued: 09/29/1998
• Est. Priority Date: 11/29/1995
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Huang, Robert Y., Dunbridge, Barry
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): PHAN, DAO LINDA
• Application Number:
  US08/592,749
• Time in Patent Office: 1,035 Days
• Field of Search: 342/372, 342/373, 455/33.3, 379/59
• US Class Current: 342/373
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A cellular communication system is provided for transmitting a large number of highly directive personalized communication beams throughout an original geographic cell of the cellular communication system. The system advantageously utilizes a phased array antenna positioned at a center location of the cell in conjunction with a spread spectrum communications method which includes code division multiple access techniques for increasing user capacity. Each of the communication beams represents user signals assigned to specific users located within the original geographic cell and are adjustable in the user'"'"'s directions. The total number of the communication beams may equal the number of users within the cell. An omnidirectional antenna is positioned in close proximity to the center location of the cell for transmitting and receiving an omnidirectional communication beam for communication with users located within approximately one half of a mile of the center location. A plurality of digital beam forming networks are employed for feeding the phased array antenna with the user signals forming the personalized communication beams.

Claims

1. A cellular communication system for transmitting adjustable personalized communication beams in individual directions of a plurality of users located within a geographical cell of the cellular communication system, each of the adjustable personalized communication beams representing user signals assigned to specific users within the geographical cell, comprising:

phased array antenna means, positioned within the geographical cell, for transmitting and receiving the adjustable personalized communication beams;

digital beam forming means for feeding the phased array antenna means with the user signals forming the adjustable personalized communication beams for transmission in the individual directions of the plurality of users and for receiving the user signals received by the phased array antenna means; and

user tracking means for providing user tracker information to the digital beam forming means, said user tracking information being a function of at least one user location vector referenced to a center of each adjustable personalized communication beam, whereby the digital beam forming means adjusts each of the user signals in response to the user tracking information so that each of the adjustable personalized communication beams is substantially centered about one of the users.

2. The cellular communication system of claim 1, wherein the phased array antenna means is located substantially at a center location of the geographical cell.

3. The cellular communication system of claim 1, further comprising:

omnidirectional antenna means, positioned in close proximity to a center location of the geographical cell, for transmitting and receiving an omnidirectional communication beam in directions of users within a predetermined range of the center location.

4. The cellular communication system of claim 1, wherein the digital beam forming means includes:

a transmitting network for transmitting the user signals represented by the adjustable personalized communication beams in directions of the plurality of users including;

(a) a plurality of signal modulators corresponding to at least the number of the users for modulating the user signals assigned to each of the users, and

(b) a plurality of transmitting digital beam forming networks for feeding the modulated user signals to the phased array antenna means such that each of the adjustable personalized communication beams is transmitted in a direction of a particular user; and

a receiving network for receiving the user signals received by the phased array antenna means including;

(a) a plurality of receiving digital beam forming networks for synthesizing the user signals, and

(b) a plurality of signal demodulators corresponding to at least the number of the users each coupled to outputs of the receiving digital beam forming networks for demodulating the user signals assigned to each of the users.

5. The cellular communication system of claim 1, wherein the user tracking means includes a plurality of amplitude comparator networks each for comparing relative amplitudes of a particular user signal represented by a first adjustable personalized communication beam and at least two other adjustable personalized communication beams adjacent to the first adjustable personalized communication beam.

6. The cellular communication system of claim 4, wherein the user tracking means includes:

a plurality of amplitude comparator networks, coupled to outputs of the demodulators, each for comparing relative amplitudes of a particular user signal represented by a first adjustable personalized communication beam and at least two other adjustable personalized communication beams adjacent to the first adjustable personalized communication beam; and

switching means for providing the user signals represented by the first adjustable personalized communication beam and the at least two other adjacent adjustable personalized communication beams to a demodulator assigned to the first adjustable personalized communication beam.

7. The cellular communication system of claim 4, wherein the signal modulators modulate the user signals using code division multiple access coded spread spectrum signals.

8. The cellular communication system of claim 4, wherein the phased array antenna means includes a plurality of radiating elements for transmitting and receiving the adjustable personalized communication beams.

9. The cellular communication system of claim 8, wherein each of the receiving digital beam forming networks includes variable amplitude and phase control elements corresponding to the number of radiating elements, and wherein each of the transmitting digital beam forming networks includes variable amplitude and phase control elements corresponding to at least the number of the users.

10. A cellular communication system for transmitting a fixed number of personalized communication beams in fixed directions covering a geographical cell of the cellular communication system, each of the personalized communication beams representing user signals assigned to specific users within the geographical cell, comprising:

phased array antenna means, positioned within the geographical cell, for transmitting and receiving the fixed personalized communication beams;

a plurality of digital beam forming networks for feeding the phased array antenna means with the user signals forming the fixed personalized communication beams and for receiving the user signals represented by the fixed personalized communication beams;

a plurality of modulating/demodulating networks corresponding to at least the number of the users for modulating and demodulating the user signals assigned to each of the users;

switching means for switching the plurality of modulating/demodulating networks between the plurality of digital beam forming networks such that each of the users is assigned to a fixed personalized communication beam providing maximum signal coverage; and

user tracking means for tracking each of the users and for providing the switching means with user tracking information, said user tracking information being a function of a signal power level of each fixed personalized communication beam, whereby the switching means switches the plurality of modulating/demodulating networks between the plurality of digital beam forming networks.

11. The cellular communication system of claim 10, wherein the phased array antenna means is located substantially at a center location of the geographical cell.

12. The cellular communication system of claim 10, further comprising:

omnidirectional antenna means, positioned in close proximity to the center location of the geographical cell, for transmitting and receiving an omnidirectional communication beam in directions of users within a predetermined range of the center location of the geographical cell.

13. The cellular communication system of claim 10, wherein the user tracking means includes a plurality of amplitude comparator networks each for comparing relative amplitudes of a particular user signal represented by a first fixed personalized communication beam and at least two other fixed personalized communication beams adjacent to the first fixed personalized communication beam.

14. The cellular communication system of claim 10, wherein the modulating/demodulating networks modulate the user signals using code division multiple access coded spread spectrum signals.

15. The cellular communication system of claim 10, wherein each of the digital beam forming networks include fixed amplitude and phase control elements.

16. The cellular communication system of claim 10, wherein the phased array antenna means includes a number of radiating elements corresponding the number of digital beam forming networks for transmitting and receiving the fixed personalized communication beams.

17. The cellular communication system of claim 10, wherein the phased array antenna means includes a plurality of radiating elements each transmitting the fixed personalized communication beams such that adjacent beams have overlapping signal coverage areas.

18. The cellular communication system of claim 17, wherein the radiating elements transmit substantially two hundred and forty of the fixed personalized communication beams, each the fixed personalized communication beams having a three degree signal coverage area and overlapping adjacent beams by approximately one and a half degrees.