METHODS AND APPARATUS FOR IMPROVED SCANNING OF A RADIO FREQUENCY (RF) BAND FOR WLANs IN AN UNKNOWN REGULATORY DOMAIN

• US 20080096501A1
• Filed: 10/23/2006
• Published: 04/24/2008
• Est. Priority Date: 10/23/2006
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Montemurro, Michael Peter, Salomone, Leonardo
• Granted Patent: US 8,433,312 B2
• Time in Patent Office: Days
• US Class Current: 455/161.1
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Methods and apparatus for use in scanning a radio frequency (RF) band for wireless local area networks (WLANs) while regulatory information for the RF band is deemed unknown are disclosed. A mobile communication device includes one or more processors and a wireless transceiver coupled to the one or more processors. In one illustrative embodiment, a processor of the mobile device utilizes the wireless transceiver to cause the RF band to be scanned using a passive scan operation on RF channels having a passive scan status. During the passive scan operation, the processor attempts to decode an information frame on the RF channel. In response to successfully decoding an information frame on the RF channel during the passive scan operation, the processor changes the passive scan status of the RF channel to an active scan status, and causes an active scan operation to be performed on the RF channel having the active scan status. The information frame that is successfully decoded may be any suitable frame of the WLAN protocol, such as a control, data, and/or management frame from a WLAN or even from other mobile device. The processor utilizes the wireless transceiver to scan additional RF channels of the RF band in the same manner, using the passive scan operation or the active scan operation based on the scan status of each RF channel. The scanning process may continue until regulatory information for the RF band is received. Advantageously, scanning of an RF band for WLANs is more efficient and power consumption of the mobile device is reduced.

Claims

1. A method for use in scanning a radio frequency (RF) band while regulatory information for the RF band is unknown, the method comprising the acts of:

scanning the RF band using a passive scan operation on RF channels having a passive scan status;

during the passive scan operation, attempting to decode an information frame on the RF channel;

in response to successfully decoding an information frame on the RF channel during the passive scan operation;

changing the passive scan status of the RF channel to an active scan status; and

performing an active scan operation on the RF channel having the active scan status.

2. The method of claim 1, further comprising:

in response to unsuccessful decoding on the RF channel during the passive scan operation;

maintaining the passive scan status of the RF channel.

3. The method of claim 1, wherein the information frame comprises one of a data, management, or control frame of a wireless local area network (WLAN).

4. The method of claim 1, wherein the information frame comprises an information frame received from a mobile communication device.

5. The method of claim 1, wherein the act of attempting to decode an information frame comprises the further act of performing a decoding process with use of an error detection code.

6. The method of claim 1, wherein the act of performing the active scan operation on the RF channel comprises the further act of:

causing a probe request to be transmitted on the RF channel; and

monitoring for a probe response in response to transmitting the probe request.

7. The method of claim 1, further comprising:

deeming the regulatory information to be unknown in response to identifying an out-of-coverage condition for a predetermined time period.

8. The method of claim 1, further comprising:

repeating the acts for a next RF channel of the RF band.

9. The method of claim 1, wherein the passive and active scan operations are adapted in accordance with an 802.11 standard.

10. The method of claim 1, further comprising:

receiving country information associated with the regulatory information; and

performing the scanning in accordance with the regulatory information.

11. The method of claim 1, wherein the act of performing the active scan operation consumes less power in the mobile communication device than the act of performing the passive scan operation, and therefore the act of successfully decoding the information frame causes the mobile communication device to consume less power while scanning.

12. A mobile communication device, comprising:

one or more processors;

a wireless transceiver coupled to the one or more processors;

a user interface which includes a visual display and a plurality of keys;

the one or more processors being operative to;

cause scanning to be performed on a radio frequency (RF) band, via the wireless transceiver, using a passive scan operation on RF channels having a passive scan status;

during the passive scan operation, attempt to decode an information frame on the RF channel;

in response to successfully decoding an information frame on the RF channel during the passive scan operation;

change the passive scan status of the RF channel to an active scan status; and

perform an active scan operation on the RF channel having the active scan status.

13. The mobile communication device of claim 12, wherein the one or more processors are further operative to:

in response to unsuccessful decoding on the RF channel during the passive scan operation;

maintain the passive scan status of the RF channel.

14. The mobile communication device of claim 12, wherein the one or more processors are further operative to:

attempt to decode an information frame by performing a decoding process with use of an error detection code.

15. The mobile communication device of claim 12, wherein the one or more processors are further operative to:

perform the active scan operation on the RF channel by causing a probe request to be transmitted on the RF channel.

16. The mobile communication device of claim 12, wherein the one or more processors are further operative to:

perform the active scan operation on the RF channel by;

causing a probe request to be transmitted on the RF channel; and

monitoring for a probe response in response to transmitting the probe request.

17. The mobile communication device of claim 12, wherein the one or more processors are further operative to:

repeating the acts for a next RF channel of the RF band.

18. The mobile communication device of claim 12, wherein the one or more processors are further operative to:

passive and active scan operations are adapted in accordance with an 802.11 standard.

19. The mobile communication device of claim 12, further comprising:

receiving country information associated with the regulatory information; and

performing the scanning in accordance with the regulatory information.

20. The mobile communication device of claim 12, wherein performing the active scan operation consumes less power in the mobile communication device than performing the passive scan operation, and therefore successfully decoding the information frame causes the mobile communication device to consume less power while scanning.

21. The mobile communication device of claim 12, wherein the information frame comprises one of a data, management, or control frame of a wireless local area network (WLAN).

22. The mobile communication device of claim 12, wherein the information frame comprises an information frame received from another mobile communication device.

23. A method for use in scanning a radio frequency (RF) band for a wireless communication network by a mobile communication device, the method comprising the acts of:

scanning RF channels of the RF band in accordance with a first scan mode;

during the scanning in accordance with the first scan mode, identifying whether valid information exists on an RF channel of the RF band; and

scanning RF channels of the RF band in accordance with a second scan mode in response to identifying that valid information exists on the RF channel of the RF band.

24. The method of claim 23, wherein the act of scanning in accordance with the second scan mode causes the mobile communication device to consume less power than the act of scanning in accordance with the first scan mode.

25. The method of claim 23, wherein the act of identifying whether valid information exists on the RF channel of the RF band comprises the further act of identifying whether the information abides by a predetermined protocol or format associated with the wireless communication network.

26. The method of claim 23, further comprising:

during the scanning in accordance with the first scan mode, attempting to decode an information frame on the RF channel; and

wherein the act of identifying whether valid information exists on the RF channel of the RF hand comprises the further act of identifying whether the information frame on the RF channel has been successfully decoded by the mobile communication device.

27. The method of claim 23, further comprising:

during the scanning in accordance with the first scan mode, attempting to decode an information frame on the RF channel; and

wherein the act of identifying that valid information exists on the RF channel of the RF band comprises the further act of identifying that an information frame from another mobile communication device has been successfully decoded.

28. A mobile communication device, comprising:

one or more processors;

a wireless transceiver coupled to the one or more processors;

a user interface which includes a visual display and a plurality of keys;

the one or more processors being operative to;

cause radio frequency (RF) channels of an RF band to be scanned, using the wireless transceiver, in accordance with a first scan mode;

during the scanning in accordance with the first scan mode, identify whether valid information exists on an RF channel of the RF band; and

cause RF channels of the RF band to be scanned, using the wireless transceiver, in accordance with a second scan mode in response to identifying that valid information exists on the RF channel of the RF band.

29. The mobile communication device of claim 28, wherein the one or more processors are further operative to perform scanning in accordance with the second scan mode to cause the mobile communication device to consume less power than the scanning in accordance with the first scan mode.

30. The mobile communication device of claim 28, wherein the one or more processors are further operative to identify whether valid information exists on the RF channel of the RF band by identifying whether the information abides by a predetermined protocol or format associated with the wireless communication network.

31. The mobile communication device of claim 28, further comprising:

wherein the one or more processors are further operative to, during the scanning in accordance with the first scan mode, attempt to decode an information frame on the RF channel; and

wherein the one or more processors are further operative to identify whether valid information exists on the RF channel of the RF band by identifying whether the information frame on the RF channel has been successfully decoded by the mobile communication device.

32. The mobile communication device of claim 28, further comprising:

wherein the one or more processors are further operative to, during the scanning in accordance with the first scan mode, attempt to decode an information frame on the RF channel; and

wherein the one or more processors are further operative to identify that valid information exists on the RF channel of the RF band by identifying that an information frame from another mobile communication device has been successfully decoded.