Channel Discovery and Disconnection in Networks Over White Spaces and Other Portions of the Spectrum

• US 20100301992A1
• Filed: 05/28/2009
• Published: 12/02/2010
• Est. Priority Date: 05/28/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Murty, Rohan N., Bahl, Paramvir, Moscibroda, Thomas, Chandra, Ranveer
• Granted Patent: US 8,179,797 B2
• Time in Patent Office: Days
• US Class Current: 340/5.1
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA

Abstract

Functionality is described for discovering a channel within an environment in which non-privileged entities have subordinate access rights to spectrum compared to privileged entities. The functionality operates by investigating spectrum units within the spectrum for the presence of the channel. In one case, the functionality operates by investigating the spectrum units in linear succession; in another case, the functionality advances in a staggered fashion over the available spectrum. Functionality is also described for handling disconnection by a node from a channel. The functionality allows the node to convey its disconnection status to other communication participants. In one case, various aspects of the functionality are implemented by performing analysis in the time domain.

Claims

1. A method, using electronic processing functionality, for extracting information from spectrum, comprising:

investigating a plurality of spectrum units in a time domain to identify a characteristic signal;

deriving information based on the characteristic signal to provide derived information; and

governing a communication among at least two nodes based on the derived information.

2. The method of claim 1, wherein the spectrum is used by both privileged entities and non-privileged entities, the non-privileged entities having subordinate rights to the spectrum compared to the privileged entities, said at least two nodes corresponding to two respective non-privileged entities.

3. The method of claim 1, wherein the derived information corresponds to a width of a channel that is being used to conduct communication, and wherein said governing comprises using the channel to conduct communication between said at least two nodes.

4. The method of claim 3, wherein the derived information also corresponds to a center frequency of the channel.

5. The method of claim 1, wherein the derived information corresponds to an indication that a node has lost a channel on which it was communicating, and wherein said governing comprising initiating a procedure to reestablish communication with the node.

6. The method of claim 1, wherein said deriving comprises detecting a width of a packet within the characteristic signal and providing the derived information based on the width of the packet.

7. The method of claim 1, wherein said deriving comprises detecting an interval between events in the characteristic signal and providing the derived information based on the interval between events.

8. The method of claim 1, wherein said deriving comprises detecting information in the characteristic signal that is indicative of an identity of an entity which has sent the characteristic signal, and providing the derived information based on the information that is detected.

9. A computer readable medium for storing computer readable instructions, the computer readable instructions providing a discovery module when executed by one or more processing devices, the computer readable instructions comprising:

logic configured to advance to a spectrum unit within the available spectrum;

logic configured to determine whether the spectrum unit is at least part of a channel, the channel being said to be discovered if it is determined that the spectrum unit is at least part of the channel; and

said logic configured to advance and said logic configured to determine repeating their respective advancing and determining operations until the channel is discovered.

10. The computer readable medium of claim 9, further comprising logic configured to derive, if a channel is discovered, at least a width of the channel based on a characteristic signal detected over the spectrum unit.

11. The computer readable medium of claim 9, wherein the channel has a width that is not known in advance of discovery of the channel.

12. The computer readable medium of claim 9, wherein said logic configured to advance and said logic configured to determine operate by examining each spectrum unit within the available spectrum in linear succession.

13. The computer readable medium of claim 12, wherein said logic configured to derive also derives a center frequency of the channel without decoding information from the spectrum.

14. The computer readable medium of claim 9, wherein said logic configured to advance and logic configured to determine operate by examining spectrum units within the available spectrum in staggered fashion, skipping over one or more spectrum units in a linear succession of spectrum units, wherein said skipping is performed to investigate the available spectrum for the presence of the channel on a class-width-by-class-width basis.

15. The computer readable medium of claim 9, wherein said logic configured to derive is configured to use time domain analysis to determine whether the spectrum unit is at least part of the channel.

16. A disconnection management module, comprising:

logic configured to detect a presence of a privileged entity operating on a channel that is being used by a first node to communicate with a second node, the first node and the second node being associated with non-privileged entities, the non-privileged entities having subordinate access rights compared to the privileged entity;

logic configured to disconnect the first node from the channel; and

logic configured to send notification information to a second node that indicates that the first node has disconnected from the channel.

17. The disconnection management module of claim 16, wherein said logic configured to send notification information is configured to use a backup channel to send the notification information to the second node.

18. The disconnection management module of claim 16, wherein said logic configured to send notification information is configured to use an alternative channel to send the notification information to the second node if a backup channel is not available.

19. The disconnection management module of claim 16, wherein the disconnection management module also includes logic configured to detect notification information sent by the second node to the first node, the notification information sent by the second node indicating that the second node has detected loss of the channel.

20. The disconnection management module of claim 19, wherein said logic configured to detect is configured to use time domain analysis to detect the notification information sent by the second node.