Distributed antenna system and method of controlling the same

• US 6,308,085 B1
• Filed: 03/08/1999
• Issued: 10/23/2001
• Est. Priority Date: 03/13/1998
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Shoki, Hiroki
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Trinh, Sonny
• Application Number:
  US09/263,872
• Time in Patent Office: 960 Days
• Field of Search: 455/561, 455/562, 455/277.1, 455/277.2, 455/133-136, 455/273, 455/278.1, 342/354, 342/372, 342/374, 342/81, 342/371
• US Class Current: 455/562.1
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

The present invention is a distributed antenna system comprising a plurality of antennas arranged in a distributed manner such that individual service areas partly overlap one another, and a centralized controller for controlling the plurality of antennas, wherein the centralized controller comprises a selection circuit for selecting at least one of the plurality of antennas and a beam forming circuit for forming at least one beam by setting desired excitation conditions for the at least one of the plurality of antennas selected.

Claims

1. A distributed antenna system comprising:

a plurality of antennas arranged in a distributed manner such that individual service areas partly overlap one another; and

a centralized controller configured to control said plurality of antennas,

wherein said centralized controller comprises;

a first selection circuit configured to select at least one of the plurality of antennas;

a transmission beam forming circuit configured to form transmission beams by adaptively setting desired excitation conditions for the at least one of the plurality of antennas selected by the first selection circuit;

a second selection circuit configured to select at least one of the plurality of antennas;

a reception beam forming circuit configured to form reception beams by adaptively setting desired excitation conditions for the at least one of the plurality of antennas selected by the second selection circuit; and

a monitor section configured to activate the transmission beam forming circuit and the reception beam forming circuit at same frequency, and to monitor a reception level of a signal transmitted from the at least one of the plurality of antennas selected by the first selection circuit, the signal being received by the at least one of the plurality of antennas selected by the second selection circuit.

2. The distributed antenna system according to claim 1, further comprising:

a first section configured to find a mutual coupling amount between the at least one of the plurality of antennas selected by the first selection circuit and the at least one of the plurality of antennas selected by the second selection circuit on the basis of the reception level monitored by the monitor section; and

a second section configured to store the mutual coupling amount found by the first section.

3. The distributed antenna system according to claim 2, further comprising:

a third section configured to update the mutual coupling amount stored.

4. The distributed antenna system according to claim 3, wherein the mutual coupling amount stored is updated at a predetermined period.

5. The distributed antenna system according to claim 2, wherein each of said first and second selection circuits selects at least one of said plurality of antennas in which the mutual coupling amount is less than a predetermined value, thereby forming a plurality of antenna groups.

6. The distributed antenna system according to claim 5, wherein said antenna groups operate at same frequency.

7. The distributed antenna system according to claim 1, wherein said centralized controller and said plurality of antennas are connected by means of optical fibers.

8. A method of controlling a distributed antenna system comprising the steps of:

selecting at least one of a plurality of antennas by a first selection circuit, the plurality of antennas being arranged in a distributed manner such that individual service areas partly overlap one another;

forming a transmission beam by setting desired excitation conditions for the at least one of the plurality of antennas selected by the first selection circuit;

selecting at least one of the plurality of antennas by a second selection circuit;

forming a reception beam by setting desired excitation conditions for the at least one of the plurality of antennas selected by the second selection circuit; and

monitoring a reception level of the transmission beam received by the at least one of the plurality of antennas in which the reception beam is formed.

9. The method according to claim 8, further comprising the steps of:

finding a mutual coupling amount between the at least one of the plurality of antennas selected by the first selection circuit and the at least one of the plurality of antennas selected by the second selection circuit on the basis of the reception level monitored; and

storing the found mutual coupling amount.

10. The method according to claim 9,

further comprising a step of updating the mutual coupling amount stored.

11. The method according to claim 10,

wherein the mutual coupling amount stored is updated at a predetermined period.

12. The method according to claim 8,

wherein each of said first and second selection circuits selects at least one of said plurality of antennas in which the mutual coupling amount is less than a predetermined value, thereby forming a plurality of antenna groups.

13. The method according to claim 12,

wherein said plurality of antenna groups operate at same frequency.