Wireless communication system and wireless station

• US 20030036404A1
• Filed: 08/06/2002
• Published: 02/20/2003
• Est. Priority Date: 08/07/2001
• Status: Active Grant

• Current Assignee: Palmira Wireless AG
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Toshimitsu, Kiyoshi, Adachi, Tomoko, Ito, Kuniaki, Kasami, Hideo
• Granted Patent: US 6,983,167 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A station determines the presence/absence of directional beam control in an access point, on the basis of received power measured when data transmitted from the access point are received, and the type of the received data. In accordance with the result of this determination, the station controls transmitting power to transmit data to the access point.

Claims

1. A wireless communication system which exchanges data between an access point and plural stations, wherein said station comprises:

a received power measurement unit which measures received power when data transmitted from said access point is received;

a received data type detection unit which detects the type of the received data;

a beam gain estimation unit which determines the presence/absence of directional beam control in said access point, on the basis of, the received power measured by said received power measurement unit, and the received data type detected by said received data type detection unit; and

a transmitter power control unit which controls transmitting power for transmitting data to said access point, in accordance with the result of the determination by said beam gain estimation unit.

2. A system according to claim 1, wherein said received data type detection unit detects whether received data are broadcast frame data or unicast frame data.

3. A system according to claim 1, wherein said beam gain estimation unit determines that space division multiple access (SDMA) is applicable at said access point, when the level of the directional beam is larger or equal to a predetermined level.

4. A system according to claim 1, further comprising:

a transmitted power detection unit which detects transmitted power when said access point transmits data.

5. A wireless communication system which exchanges data between an access point and plural stations by CSMA (Carrier Sense Multiple Access), wherein said station comprises:

a received power measurement unit which measures received power when data transmitted from said access point is received;

a received data type detection unit which detects the type of the received data;

a beam gain estimation unit which determines the presence/absence of directional beam control in said access point, on the basis of the received power measured by said received power measurement unit, and the received data type detected by said received data type detection unit;

a transmitter power control unit which controls transmitting power for transmitting data to said access point, in accordance with the result of the determination by said beam gain estimation unit; and

a carrier sense control unit which controls the carrier sense level of said station in accordance with the result of the determination by said beam gain estimation unit.

6. A system according to claim 5, wherein said received data type detection unit detects whether received data are broadcast frame data or unicast frame data.

7. A system according to claim 5, further comprising:

a transmitted power detection unit which detects transmitted power when said access point transmits data.

8. A wireless communication system which exchanges data between an access point and plural stations, wherein said station comprises:

a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;

a beam gain estimation unit which determines the presence/absence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit; and

a transmitting power control unit which controls transmitting power for transmitting data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control.

9. A system according to claim 8, wherein when said beam gain estimation unit determines that said access point is performing directional beam control, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.

10. A system according to claim 8, wherein

when determining that said access point is performing directional beam control, said beam gain estimation unit further checks whether space division multiple access is applicable at said access point, and

when said beam gain estimation unit determines that said access point is performing directional beam control, and that space division multiple access is applicable at said access point, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.

11. A system according to claim 8, further comprising:

a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.

12. A wireless communication system which exchanges data between an access point and plural stations by CSMA (Carrier Sense Multiple Access), wherein said station comprises:

a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;

a beam gain estimation unit which determines the presence/absence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit;

a transmitting power control unit which controls transmitting power to transmit data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control; and

a carrier sense control unit which controls the carrier sense level of said station in accordance with the result of the determination by said beam gain estimation unit.

13. A system according to claim 12, wherein when said beam gain estimation unit determines that said access point is performing directional beam control, said carrier sense control unit raises the carrier sense level of said station to such an extent that the carrier sense function does not degrade.

14. A system according to claim 12, wherein

when determining that said access point is performing directional beam control, said beam gain estimation unit further checks whether space division multiple access is applicable at said access point, and

when said beam gain estimation unit determines that said access point is performing directional beam control, and that space division multiple access is applicable at said access point, said carrier sense control unit raises the carrier sense level of said station to such an extent that the carrier sense function does not degrade.

15. A system according to claim 12, further comprising:

a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.

16. A wireless station which exchanges data with an access point, comprising:

a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;

a beam gain estimation unit which determines the presence/absence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit; and

a transmitting power control unit which controls transmitting power for transmitting data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control.

17. A station according to claim 16, wherein when said beam gain estimation unit determines that said access point is performing directional beam control, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.

18. A station according to claim 16, wherein

when determining that said access point is performing directional beam control, said beam gain estimation unit further checks whether space division multiple access is applicable at said access point, and

when said beam gain estimation unit determines that said access point is performing directional beam control, and that space division multiple access is applicable at said access point, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.

19. A station according to claim 16, further comprising:

a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.

20. A wireless station which exchanges data with an access point by CSMA (Carrier Sense Multiple Access), comprising:

a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;

a beam gain estimation unit which determines the presence/absence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit, and the first and second transmitted powers detected by said transmitted power detection unit;

a transmitting power control unit which controls transmitting power for transmitting data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control; and

a carrier sense control unit which controls the carrier sense level of said station in accordance with the result of the determination by said beam gain estimation unit.

21. A wireless station according to claim 20, further comprising:

a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.