RANDOM ACCESS IN DYNAMIC AND SHARED SPECTRUMS

• US 20150057011A1
• Filed: 02/24/2013
• Published: 02/26/2015
• Est. Priority Date: 02/24/2012
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Di Girolamo, Rocco, Freda, Martino M., Gauvreau, Jean-Louis, Laughlin, Scott, Purkayastha, Debashish
• Granted Patent: US 9,363,829 B2
• Time in Patent Office: Days
• US Class Current: 455/454
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]

Abstract

Systems and methods for using a communication system in a spectrum are provided. For example, a random access or RACH procedure may be performed where the random access or RACH procedure may be configured to reduce secondary interference and/or to be used in a pixel-based environment. The random access or RACH procedure may include selecting a RACH preamble; sending a RACH preamble and/or format information; determining a transmission power of the RACH preamble and/or the format information; determining a random access radio network temporary identifier (RA-RNTI) and preamble ID associated with the RACH preamble; and/or selecting a physical RACH (PRACH).

Claims

1. A method for configuring a random access channel (RACH) procedure used by a wireless transmit/receive unit (WTRU) in a communication system, the method comprising:

determining whether a secondary user is present in an operating channel; and

performing a RACH procedure based on the determination, wherein based on a determination that the secondary user is absent in the operating channel of the communication system, a first RACH procedure is performed, and based on a determination that the secondary user is present in the operating channel of the communication system, a second RACH procedure different from the first RACH procedure is performed.

2. The method of claim 1, wherein the second RACH procedure is based on a type of the secondary user.

3. The method of claim 1, wherein the second RACH procedure is configured by an eNB.

4. The method of claim 1, further comprising receiving information relating to whether the secondary user is present in the operating channel, wherein the determining is based on the received information.

5. The method of claim 4, wherein the information relating to whether the secondary user is present in the operating channel is received from an eNB, and the eNB uses a feature detection to determine whether the secondary user is present in the operating channel.

6. The method of claim 4, wherein the information relating to whether the secondary user is present or absent in the operating channel of the communication system is received via an RRC configuration message.

7. The method of claim 1, wherein the WTRU sends a preamble at a power level higher than a default power level if the secondary user is present in the operating channel of the communication system.

8. A method for sending a random access channel (RACH) from a wireless transmit/receive unit (WTRU), the method comprising:

determining whether a communication channel is available during a RACH resource based on sensing on the communication channel; and

determining a timing for sending a RACH preamble based on whether the communication channel is available during the RACH resource, wherein the RACH preamble is determined to be sent during the RACH resource when the communication channel is available during the RACH resource, and the RACH preamble is determined to be sent during a subsequent RACH resource when the communication channel is unavailable during the RACH resource.

9. The method of claim 8, further comprising sending the RACH preamble from the WTRU during an immediately subsequent RACH resource without increasing a power of the RACH preamble when the communication channel is unavailable during the RACH resource.

10. The method of claim 8, further comprising sending the RACH preamble from the WTRU during an immediately subsequent RACH resource with an increased power during the subsequent RACH resource when the communication channel is unavailable during the RACH resource.

11. The method of claim 8, further comprising sending the RACH preamble over multiple consecutive RACH resources when the multiple consecutive RACH resources are available.

12. The method of claim 8, further comprising when multiple consecutive RACH resources are available and the communication channel is unavailable during an entire RACH resource, sending the RACH preamble with an increased power during the subsequent RACH resource of the multiple consecutive RACH resources.

13. The method of claim 8, further comprising:

adjusting power level for sending the RACH preamble based on whether the communication channel is available, wherein a default power level is used when the communication channel is available, and an increased power relative to the default power level is used when the communication channel is unavailable.

14. The method of claim 8, further comprising sensing the communication channel by performing at least one of an energy detection or a feature detection.

15. The method of claim 14, wherein the feature detection is used to determine whether the communication channel is occupied by a WiFi system, the method further comprising sending the RACH preamble when the communication channel is not occupied by the WiFi system.

16. The method of claim 8, further comprising reducing a length of the RACH preamble.

17. The method of claim 16, further comprising sending the reduced-length RACH preamble once following a Listen Before Talk (LBT) time of the WTRU.

18. The method of claim 16, further comprising sending the reduced-length RACH preamble multiple times before an end of the RACH resource.

19. The method of claim 16, further comprising sending the reduced-length RACH preamble once at a random time during the RACH resource.

20. The method of claim 19, wherein sending the reduced-length RACH preamble once at a random time during the RACH resource comprises:

selecting a random time for the WTRU to perform a Listen Before Talk (LBT) procedure; and

performing the LBT procedure the selected time and sending the RACH preamble based on whether the communication channel is available, wherein, the RACH preamble is sent when the communication channel is available for the entire time of the LBT procedure, and the LBT procedure is repeated when the communication channel is unavailable during the LBT procedure.

21. A method for using a communication system comprising a wireless transmit/receive unit (WTRU) in a spectrum, the method comprising:

selecting a random access channel (RACH) procedure as a function of a presence or an absence of a secondary user in an operating channel of the communication system; and

performing the selected random access channel (RACH) procedure.

22. The method of claim 21, further comprising configuring the RACH procedure to reduce secondary interference.

23. The method of claim 21, wherein performing the selected RACH procedure comprises sending at least one of a RACH preamble and format information.

24. The method of claim 23, wherein performing the selected RACH procedure comprises determining a transmission power for at least one of the RACH preamble and the format information.

25. A method for configuring a random access channel (RACH) procedure used by a wireless transmit/receive unit (WTRU) in a communication system, the method comprising:

determining, at an eNB, whether a secondary user is present in an operating channel of the communication system; and

configuring the RACH procedure at the WTRU based on whether the secondary user is present in the operating channel of the communication system.

26. The method of claim 25, further comprising reducing a length of a RACH preamble.

27. The method of claim 26, further comprising sending the reduced-length RACH preamble multiple times before an end of a RACH resource.

28. The method of claim 26, further comprising sending the reduced-length RACH preamble once at a random time during a RACH resource.

29. The method of claim 25, further comprising:

receiving, at a WTRU in a pixel-based environment, an indication of a first maximum transmit power defined for a group of pixels of the pixel-based environment;

sending a RACH preamble with the first maximum transmit power;

receiving, at the WTRU in the pixel-based environment, an indication of a second maximum transmit power specific to a location of the WTRU in the pixel-based environment; and

completing the selected RACH procedure using the second maximum transmit power.

30. A wireless transmit/receive unit (WTRU) comprising:

a processor configured to;

determine whether a secondary user is present in an operating channel of a communication system; and

perform a random access channel (RACH) procedure based on the determination, wherein based on a determination that the secondary user is absent in the operating channel, a first RACH procedure is performed, and based on a determination that the secondary user is present in the operating channel, a second RACH procedure different from the first RACH procedure is performed.

31. The WTRU of claim 30, wherein the second RACH procedure is based on a type of the secondary user.

32. The WTRU of claim 30, wherein the second RACH procedure is configured by an eNB.

33. The WTRU of claim 30, wherein the processor is configured to receive information relating to whether the secondary user is present in the operating channel, and wherein the processor is configured to determine whether the secondary user is present in the operating channel based on the received information.

34. The WTRU of claim 33, wherein the information relating to whether the secondary user is present or absent in the operating channel is received from an eNB, and the eNB uses feature detection to determine whether the secondary user is present in the operating channel.

35. The WTRU of claim 33, wherein the information relating to whether the secondary user is present in the operating channel is received via an RRC configuration message.

36. The WTRU of claim 30, wherein the WTRU sends a preamble at a power level higher than a default power level when the secondary user is present in the operating channel.

37. A wireless transmit/receive unit (WTRU) comprising:

a processor configured to

determine whether a communication channel is available during a random access channel (RACH) resource based on sensing on the communication channel; and

determine a timing for sending a RACH preamble based on whether the communication channel is available during the RACH resource, wherein the RACH preamble is determined to be sent during the RACH resource when the communication channel is available during the RACH resource, and the RACH preamble is determined to be sent during a subsequent RACH resource when the communication channel is unavailable during the RACH resource.

38. The WTRU of claim 37, wherein the processor is configured to send the RACH preamble during an immediately subsequent RACH resource without increasing a power of the RACH preamble when the communication channel is unavailable during a RACH resource.

39. The WTRU of claim 37, wherein the processor is configured to resend the RACH preamble with an increased power during an immediately subsequent RACH resource when the communication channel is unavailable during a RACH resource.

40. The WTRU of claim 37, wherein the processor is configured to send the RACH preamble over multiple consecutive RACH resources when the multiple consecutive RACH resources are available.

41. The WTRU of claim 37, wherein the processor is configured to send the RACH preamble with an increased power during a subsequent RACH resource of multiple consecutive RACH resources if the multiple consecutive RACH resources are available and the communication channel is unavailable during an entire RACH resource.

42. The WTRU of claim 37, wherein the WTRU is configured to:

send the RACH preamble with a default power level when the communication channel is available; and

send the RACH preamble with an increased power relative to the default power level when the communication channel is unavailable.

43. The WTRU of claim 37, wherein the WTRU senses the communication channel by performing at least one of an energy detection and a feature detection.

44. The WTRU of claim 43, wherein the processor is configured to perform a feature detection for determining whether the communication channel is occupied by a WiFi system and to send the RACH preamble when the communication channel is not occupied by the WiFi system.

45. The WTRU of claim 37, wherein the processor is configured to reduce a length of the RACH preamble.

46. The WTRU of claim 45, wherein the processor is configured to send the reduced-length RACH preamble once following a Listen Before Talk (LBT) time of the WTRU.

47. The WTRU of claim 45, wherein the processor is configured to send the reduced-length RACH preamble multiple times before an end of the RACH resource.

48. The WTRU of claim 45, wherein the processor is configured to send the reduced-length RACH preamble once at a random time during the RACH resource.

49. The WTRU of claim 48, wherein the processor is configured to:

select a random time for performing a Listen Before Talk (LBT) procedure;

perform the LBT procedure for the selected time; and

send the RACH preamble based on whether the communication channel is available, wherein, the processor is configured to send the RACH preamble when the communication channel is available for the entire time of the LBT procedure, and to repeat performing the LBT procedure when the communication channel is unavailable during the LBT procedure.

50. A wireless transmit/receive unit (WTRU) comprising:

a processor configured to;

select a random access channel (RACH) procedure as a function of a presence or an absence of a secondary user in an operating channel of a communication system; and

perform the selected random access channel (RACH) procedure.

51. The WTRU of claim 50, wherein the RACH procedure is configured to reduce secondary interference.

52. The WTRU of claim 51, wherein the processor is configured to perform the selected RACH procedure at least in part by sending at least one of a RACH preamble or format information.

53. The WTRU of claim 52, wherein the processor is configured to perform the selected RACH procedure at least in part by determining a transmission power for at least one of the RACH preamble or the format information.

54. A wireless transmit/receive unit (WTRU) comprising:

a processor configured to;

receive information indicating whether a secondary user is present in an operating channel of the communication system; and

configure the RACH procedure when the secondary user is present in the operating channel of the communication system.

55. The WTRU of claim 54, wherein the processor is configured to reduce a length of a RACH preamble.

56. The WTRU of claim 55, wherein the processor is configured to send the reduced-length RACH preamble a plurality of times before an end of a RACH resource.

57. The WTRU of claim 55, wherein the processor is configured to send the reduced-length RACH preamble once at a random time during a RACH resource.

58. The WTRU of claim 55, wherein the WTRU is in a pixel-based environment, and the processor is further configured to:

receive an indication of a first maximum transmit power defined for a group of pixels of the pixel-based environment;

send the RACH preamble with the first maximum transmit power;

receive an indication of a second maximum transmit power specific to a location of the WTRU in the pixel-based environment; and

complete the selected RACH procedure using the second maximum transmit power.