METHOD AND APPARATUS FOR DISCOVERING CENTRAL NODES IN WIRELESS COMMUNICATION SYSTEM

• US 20150016324A1
• Filed: 07/15/2014
• Published: 01/15/2015
• Est. Priority Date: 07/15/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yoon, Sung-Rok, Oh, Jong-Ho, Chang, Sang-Hyun, Jo, O-Hyun, Ha, Kil-Sik
• Granted Patent: US 9,661,575 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and apparatus for reducing power consumption in a mobile device of a wireless communication system when discovering a central node is provided. The method for operating of a terminal for discovering at least one central node in a wireless communication system includes: generating a probe request signal and transmitting the probe request signal to at least one central node; after transmitting the probe request signal, switching from a normal mode to a low power mode and driving the terminal in the low power mode; in response to a mode switch instruction signal being received from the central node, switching the terminal from the low power mode to the normal mode; and receiving a probe response signal to the probe request signal from the central node in the normal mode.

Claims

1. A method for operating a terminal in a wireless communication system, the method comprising:

transmitting a probe request signal to at least one central node;

after transmitting the probe request signal, switching from a normal mode to a low power mode to drive the terminal in the low power mode;

in response to a mode switch instruction signal being received from the at least one central node, switching the terminal from the low power mode to the normal mode; and

receiving a probe response signal responsive to the probe request signal from the at least one central node in the normal mode.

2. The method of claim 1, wherein the mode switch instruction signal comprises a low power preamble.

3. The method of claim 2, wherein the low power preamble comprises at least one of a preamble having a sampling rate relatively lower than that of a normal mode preamble, and a binary sequence.

4. The method of claim 2, wherein the low power preamble comprises at least one of a switching field to guarantee a time that the terminal is requested to switch from the low power mode to the normal mode, and identification information of the terminal.

5. The method of claim 2, wherein the low power preamble is received via a specific sub channel selected from among a plurality of sub channels.

6. The method of claim 1, wherein the probe request signal comprises identification information of the terminal.

7. The method of claim 1, wherein

the terminal comprises a normal receiver and a low power receiver,

wherein the low power receiver is driven in the low power mode, and

wherein the at least one central node comprises an access point (AP) of a wireless local area network (WLAN) system and the terminal comprises a station of the WLAN system.

8. The method of claim 1, further comprising receiving information on a time for transmitting the mode switch instruction signal and the probe response signal.

9. A method for operating a central node of a wireless communication system, the method comprising:

generating a probe response signal in response to a probe request signal being received from at least one terminal;

waiting for the probe response signal to be transmitted;

transmitting an instruction signal to the terminal, wherein the instruction signal includes instructions to switch the terminal from a normal mode to a low power mode; and

transmitting the probe response signal to the terminal.

10. The method of claim 9, wherein the mode switch instruction signal comprises a low power preamble.

11. The method of claim 10, wherein the low power preamble comprises at least one of a preamble having a sampling rate relatively lower than that of a normal mode preamble, and a binary sequence.

12. The method of claim 10, wherein the low power preamble comprises at least one of a switching field to guarantee a time that the terminal is requested to switch from the low power mode to the normal mode, and identification information of the terminal.

13. The method of claim 10, wherein the low power preamble is transmitted via a specific sub channel selected from among a plurality of sub channels.

14. The method of claim 9, wherein the probe request signal comprises identification information of the terminal.

15. The method of claim 9, further comprising transmitting information on a time for transmitting the mode switch instruction signal and the probe response signal.

16. The method of claim 9, wherein the central node comprises an access point (AP) of a wireless local area network (WLAN) system and the terminal comprises a station of the WLAN system.

17. A terminal of a wireless communication system, the terminal comprising:

a transmitter configured to transmit a probe request signal to at least one central node;

a controller configured to, after transmission of the probe request signal, switch from a normal mode to a low power mode to drive the terminal in the low power mode; and

, in response to a mode switch instruction signal being received from the at least one central node, switch the terminal from the low power mode to the normal mode; and

a receiver configured to receive a probe response signal responsive to the probe request signal from the at least one central node in the normal mode.

18. The terminal of claim 17, wherein the mode switch instruction signal comprises a low power preamble.

19. The terminal of claim 18, wherein the low power preamble comprises at least one of a preamble having a sampling rate relatively lower than that of a normal mode preamble, and a binary sequence.

20. The terminal of claim 18, wherein the low power preamble comprises at least one of a switching field to guarantee a time that the terminal is requested to switch from the low power mode to the normal mode, identification information of the terminal.

21. The terminal of claim 18, wherein the low power preamble is received via a specific sub channel selected from among a plurality of sub channels.

22. The terminal of claim 17, wherein the probe request signal comprises identification information of the terminal.

23. The terminal of claim 22, wherein:

the terminal comprises a normal receiver and a low power receiver,

wherein the controller is configured to drive the terminal in the low power mode by driving the low power receiver, and

wherein the at least one central node comprises an access point (AP) of a wireless local area network (WLAN) system and the terminal comprises a station of the WLAN system.

24. The terminal of claim 17, wherein the receiver is further configured to receive information on a time for transmitting the mode switch instruction signal and the probe response signal.

25. A central node of a wireless communication system, the central node comprising:

a receiver configured to receive a probe request signal from at least one terminal;

a controller configured to generate a probe response signal in response to the probe request signal being received, wait for the probe response signal to be transmitted, and generate an instruction signal to instruct to switch the terminal from a normal mode to a low power mode; and

a transmitter configured to transmit the instruction signal and transmit the probe response signal to the terminal after transmitting the instruction signal.

26. The central node of claim 25, wherein the mode switch instruction signal comprises a low power preamble.

27. The central node of claim 26, wherein the low power preamble comprises at least one of a preamble having a sampling rate relatively lower than that of a normal mode preamble, and a binary sequence.

28. The central node of claim 26, wherein the low power preamble comprises at least one of a switching field to guarantee a time that the terminal is requested to switch from the low power mode to the normal mode, and identification information of the terminal.

29. The central node of claim 26, wherein the low power preamble is transmitted via a specific sub channel selected from a plurality of sub channels.

30. The central node of claim 25, wherein the probe request signal comprises identification information of the terminal.

31. The central node of claim 25, wherein the transmitter is further configured to transmit information on a time for transmitting the mode switch instruction signal and the probe response signal.

32. The central node of claim 25, wherein the central node comprises an access point (AP) of a wireless local area network (WLAN) system and the terminal comprises a station of the WLAN system.