COMMUNICATION METHODS AND APPARATUS WHICH MAY BE USED IN THE ABSENCE OR PRESENCE OF BEACON SIGNALS

• US 20070206554A1
• Filed: 01/10/2007
• Published: 09/06/2007
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Li, Junyi, Richardson, Tom, Lane, Frank
• Granted Patent: US 8,902,866 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04J 3/0602 Systems characterised by the synchronising information used
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 36/16 Performing reselection for specific purposes
• CPC Class Codes: H04W 36/24 Reselection being triggered by specific parameters
• CPC Class Codes: H04W 40/24 Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 40/244 using a network of reference devices, e.g. beaconing
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 76/14 Direct-mode setup
• CPC Class Codes: H04W 8/005 : Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/042 : Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/02 : Terminal devices
• CPC Class Codes: H04W 88/04 : adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 88/06 : adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/10 : adapted for operation in multiple networks, e.g. multi-mode access points
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

Wireless devices, e.g., in a cognitive radio network, discover and use locally available usable spectrum for communication. Beacon signaling facilitates available spectrum discovery, spectrum usage coordination, and device identification. A wireless terminal, which may have entered a new area and powered up, monitors to detect for the presence of beacon signals in a communications band. When the wireless terminal fails to detect a beacon, the wireless terminal assumes that the spectrum is available and transmits its user beacon signal thereby providing notification of its presence in the area to other wireless terminals. The wireless terminal maintains a coordinated timing relationship between its beacon transmit interval and beacon detect interval, which are performed on an ongoing basis. The combination of beacon TX interval and beacon monitoring interval represents a small fraction of total time, allowing for power conservation. The coordinated timing relationship, known to peers, facilitates efficient peer-peer communications session establishment.

Claims

1. A method of operating a wireless communications device, comprising:

monitoring during a first period of time to detect at least a portion of a beacon signal including at least one beacon symbol in a first communications band; and

when a beacon signal portion including at least one beacon symbol is not detected during said first period of time, transmitting a first signal during a second period of time following said first period of time.

2. The method of claim 1, wherein said second period of time has a fixed time relationship with said first period of time.

3. The method of claim 1, wherein said second period of time has a predetermined time offset from the start of said first period of time.

4. The method of claim 1, wherein said first signal is at least a portion of a second beacon signal including at least one beacon symbol.

5. The method of claim 4, wherein said detected portion of a beacon signal communicates an identification value.

6. The method of claim 5, wherein said identification value is one of a device identifier and a user identifier.

7. The method of claim 4, wherein said first signal is transmitted in said first communications band.

8. The method of claim 7, further comprising transmitting user data in addition to said first signal.

9. The method of claim 8, wherein said first signal is transmitted prior to said user data, said first signal and said user data being transmitted during non-overlapping time periods.

10. The method of claim 9, wherein transmitting said user data includes transmitting the user data into the first band.

11. The method of claim 9, further comprising:

monitoring for a response to said user data transmission from another device with which said wireless communications device is communicating on a peer to peer basis.

12. A wireless communications device, comprising:

a beacon detection module for detecting receipt of at least one beacon symbol communicated in a first communications band;

a transmitter; and

a transmission control module for controlling signal transmission as a function of an output of said beacon detection module, said transmission control module controlling said transmitter to transmit a first signal during a second period of time following a first period of time when a beacon signal portion including at least one beacon symbol is not detected during said first period of time.

13. The device of claim 12, wherein said second period of time has a fixed time relationship with said first period of time.

14. The device of claim 12, wherein said second period of time has a predetermined time offset from the start of said first period of time.

15. The device of claim 12, further comprising:

a beacon symbol generation module; and

wherein said first signal includes at least one beacon symbol.

16. The device of claim 15, further comprising:

a beacon information detection module for determining an identification value communicated by a detected portion of a beacon signal.

17. The device of claim 16, wherein said identification value is one of a device identifier and a user identifier.

18. The device of claim 15, further comprising:

a receiver for receiving beacon signal portions transmitted in said first communications band; and

a control module for controlling the band in which said receiver and transmitter operate, said receiver and transmitter being controlled to use the same band in a time division multiplexed basis.

19. The device of claim 18, further comprising:

a user data transmission control module for controlling transmission of user data in addition to said first signal in said first communications band.

20. The device of claim 19,

wherein said first signal is transmitted prior to said user data;

and

wherein said user data transmission control module controls transmission of said user data to occur in a transmission time period which does not overlap transmission of said first signal.

21. The device of claim 20, wherein said user data transmission control module controls transmission of user data so tat user data is transmitted into the first band.

22. The device of claim 20, further comprising:

a response detection module for detecting a response to said user data transmission from another device with which said wireless communications device is communicating on a peer to peer basis.

23. A wireless communications device, comprising:

means for detecting beacon signals for detecting receipt of at least one beacon symbol communicated in a first communications band;

means for transmitting; and

means for controlling said means for transmitting for controlling signal transmission as a function of an output of said means for detecting beacon signals, said means for controlling controlling said means for transmitting to transmit a first signal during a second period of time following a first period of time when a beacon signal portion including at least one beacon symbol is not detected during said first period of time.

24. The device of claim 23, wherein said second period of time has a fixed time relationship with said first period of time.

25. The device of claim 23, wherein said second period of time has a predetermined time offset from the start of said first period of time.

26. The device of claim 23, further comprising:

means for generating beacon symbols; and

wherein said first signal includes at least one beacon symbol.

27. The device of claim 26, further comprising:

means for recovering information from beacon signals for determining an identification value communicated by a detected portion of a beacon signal.

28. The device of claim 27, wherein said identification value is one of a device identifier and a user identifier.

29. A computer readable medium embodying machine executable instructions for implementing a method of operating a wireless communications device, the method comprising:

monitoring during a first period of time to detect at least a portion of a beacon signal including at least one beacon symbol in a first communications band; and

when a beacon signal portion including at least one beacon symbol is not detected during said first period of time, transmit a first signal during a second period of time following said first period of time.

30. The computer readable medium of claim 29, wherein said second period of time has a fixed time relationship with said first period of time.

31. The computer readable medium of claim 29, wherein said second period of time has a predetermined time offset from the start of said first period of time, the computer readable medium further includes machine executable instructions including the predetermined time offset.

32. The computer readable medium of claim 29, wherein said first signal is at least a portion of a second beacon signal including at least one beacon symbol.

33. The computer readable medium of claim 32, wherein said detected portion of a beacon signal communicates an identification value, the computer readable medium further embodying machine executable instruction for recovering an identification value from said detected portion of a beacon signal.

34. The method of claim 33, wherein said identification value is one of a device identifier and a user identifier.

35. An apparatus comprising:

a processor configured to;

monitor during a first period of time to detect at least a portion of a beacon signal including at least one beacon symbol in a first communications band; and

when a beacon signal portion including at least one beacon symbol is not detected during said first period of time, to transmit a first signal during a second period of time following said first period of time.

36. The apparatus of claim 35, wherein said second period of time has a fixed time relationship with said first period of time.

37. The apparatus of claim 35, wherein said second period of time has a predetermined time offset from the start of said first period of time, and wherein said processor is further configured to:

use the predetermined time offset in determining the start of the transmission time of said first signal.

38. The apparatus of claim 35, wherein said first signal is at least a portion of a second beacon signal including at least one beacon symbol.

39. The apparatus of claim 38, wherein said detected portion of a beacon signal communicates an identification value;

and

wherein the processor is further configured to;

recover an identification value from said detected portion of a beacon signal.

40. The apparatus of claim 39, wherein said identification value is one of a device identifier and a user identifier.