LTE-U uplink waveform and variable multi-subframe scheduling

• US 10,588,162 B2
• Filed: 08/21/2017
• Issued: 03/10/2020
• Est. Priority Date: 09/23/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ji, Tingfang, Luo, Tao, Bhushan, Naga, Malladi, Durga Prasad, Wei, Yongbin, Gaal, Peter, Damnjanovic, Aleksandar, Chen, Wanshi, Yerramalli, Srinivas
• Primary Examiner(s): Phunkulh, Bob A
• Application Number:
  US15/682,219
• Publication Number:
  US 20170347382A1
• Time in Patent Office: 932 Days
• Field of Search: None
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: H04J 3/16 in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted H04J3/17, H04J3/24 take precedence
• CPC Class Codes: H04L 5/0041 Frequency-non-contiguous
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• 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
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

Uplink waveforms for operating long term evolution (LTE) in an unlicensed band (i.e., long term evolution-unlicensed (LTE-U) communication) are disclosed. Carrier aggregation (CA) and standalone (SA) are disclosed. LTE on the licensed channel may provide both control and data, LTE on the unlicensed channel may provide data. Managing variable transmission time interval (TTI) continuous transmission is disclosed for transmission over multiple subframes of an unlicensed carrier in LTE-U. Listen-before-talk (LBT) requirements of unlicensed carriers provide for additional channel occupancy constraints when scheduling resources for multiple UEs for variable TTI continuous uplink transmissions over multiple subframes. A joint control channel is disclosed that provides control information for all of the potentially available subframes to be scheduled for the uplink transmissions. In addition to management of the variable TTI continuous transmissions, adjustments to uplink signal parameters are also disclosed that address the constraints due to the LBT requirements of unlicensed carriers.

Claims

1. A method of wireless communication, comprising:

selecting, by a base station, one or more downlink subframes for transmission of a joint control channel for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier;

setting, by the base station, a size of the joint control channel;

selecting, by the base station, an aggregation level for association with the joint control channel;

transmitting, by the base station, the joint control channel over the one or more selected downlink subframes;

generating, by the base station, an individual control channel with additional control information for a user equipment (UE); and

transmitting, by the base station, the individual control channel to the UE, wherein the additional control information supersedes control information contained in the joint control channel.

2. The method of claim 1, wherein the selecting includes:

selecting beginning on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

3. The method of claim 1, wherein the one or more selected downlink subframes is one of:

cell-specific or UE-specific.

4. The method of claim 3, wherein the joint control channel is cell-specific, the method further comprising:

adding an uplink grant in the joint control channel associated with each UE located in a cell served by the base station.

5. The method of claim 3, wherein the joint control channel is UE-specific, the method further comprising:

assigning one of the one or more selected downlink subframes to a specific UE for an uplink grant associated with the specific UE.

6. The method of claim 1, wherein the size is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.

7. The method of claim 1, wherein the size includes two or more control sizes selected according to one or more available uplink subframes for the variable TTI transmission.

8. The method of claim 1, wherein the selecting the aggregation level includes:

selecting the aggregation level from a plurality of aggregation levels as a function of available uplink subframes for the variable TTI transmission.

9. The method of claim 1, further comprising:

selecting a resource set size for a downlink control channel as a function of available uplink subframes for the variable TTI transmission.

10. The method of claim 1, further comprising:

indicating, by the base station, in the joint control channel for a user equipment (UE) to transmit a same transport block over each of the multiple uplink subframes designated for the variable TTI transmission.

11. The method of claim 10, wherein the same transport block includes one or more of:

uplink control signals and uplink data signals.

12. An apparatus configured for wireless communication, comprising:

means for selecting one or more downlink subframes for transmission of a joint control channel for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier;

means for setting, a size of the joint control channel;

means for selecting an aggregation level for association with the joint control channel;

means for transmitting the joint control channel over the one or more selected downlink subframes;

means for generating an individual control channel with additional control information for a user equipment (UE); and

means for transmitting the individual control channel to the UE, wherein the additional control information supersedes control information contained in the joint control channel.

13. The apparatus of claim 12, wherein the means for selecting includes:

means for selecting beginning on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

14. The apparatus of claim 12,

wherein the joint control channel is cell-specific, and

wherein the apparatus further comprises:

means for adding an uplink grant in the joint control channel associated with each UE located in a cell.

15. The apparatus of claim 12, wherein the size is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.

16. A computer program product for wireless communications in a wireless network, comprising:

a non-transitory computer-readable medium having program code recorded thereon, the program code including;

program code for causing a computer to select one or more downlink subframes for transmission of a joint control channel for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier;

program code for causing the computer to set a size of the joint control channel;

program code for causing the computer to select an aggregation level for association with the joint control channel;

program code for causing the computer to transmit the joint control channel over the one or more selected downlink subframes;

program code for causing the computer to generate an individual control channel with additional control information for a user equipment (UE); and

program code for causing the computer to transmit the individual control channel to the UE, wherein the additional control information supersedes control information contained in the joint control channel.

17. The computer program product of claim 16, wherein the program code for causing the computer to select includes:

program code for causing the computer to select beginning on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

18. The computer program product of claim 16,

wherein the joint control channel is cell-specific, and

wherein the program code further includes:

program code for causing the computer to add an uplink grant in the joint control channel associated with each UE located in a cell.

19. The computer program product of claim 16, wherein the size is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.

20. An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor,

wherein the at least one processor is configured;

to select one or more downlink subframes for transmission of a joint control channel for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier;

to set a size of the joint control channel;

to select an aggregation level for association with the joint control channel;

to transmit the joint control channel over the one or more selected downlink subframes;

to generate an individual control channel with additional control information for a user equipment (UE); and

to transmit the individual control channel to the UE, wherein the additional control information supersedes control information contained in the joint control channel.

21. The apparatus of claim 20, wherein, when selecting, the at least one processor is configured to:

select beginning on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

22. The apparatus of claim 20,

wherein the joint control channel is cell-specific, and

wherein the at least one processor is further configured to:

add an uplink grant in the joint control channel associated with each UE located in a cell.

23. The apparatus of claim 20, wherein the size is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.

24. A method of wireless communication, comprising:

receiving, by a user equipment (UE), from a base station, and over one or more downlink subframes, a joint control channel, for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier, with control information;

receiving, by the UE and from the base station, an individual control channel with additional control information;

determining, by the UE, whether the UE received the individual control channel without previously successfully receiving the joint control channel; and

performing, by the UE, an action when the UE received the individual control channel without previously successfully receiving the joint control channel.

25. The method of claim 24, wherein the one or more downlink subframes begin on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

26. The method of claim 24, further comprising:

monitoring the joint control channel over the one or more downlink subframes for uplink grants identified for the UE.

27. The method of claim 24, further comprising:

monitoring one or more of the one or more downlink subframes identified for the UE for the joint control channel having uplink grants directed to the UE.

28. The method of claim 24, wherein a size of the joint control channel is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.

29. The method of claim 28, wherein the size of the joint control channel includes one of two or more control sizes selected according to one or more available uplink subframes for the variable TTI transmission.

30. The method of claim 24, further comprising:

mapping control information from the joint control channel using an aggregation level received from the base station, wherein the aggregation level is one of a plurality of aggregation levels selected as a function of available uplink subframes for the variable TTI transmission.

31. The method of claim 24, further comprising:

receiving a resource set size indication for a downlink control channel, wherein the resource set size is a function of available uplink subframes for the variable TTI transmission.

32. The method of claim 24,

wherein the UE has previous control information contained within the joint control channel, and

wherein the additional control information supersedes the previous control information contained in the joint control channel.

33. The method of claim 24,

wherein the joint control channel is not successfully received by the UE, and

wherein performing the action comprises one of:

declaring an error event;

or

beginning uplink transmission of an uplink signal when a successful clear channel access (CCA) is detected by the UE.

34. The method of claim 33, wherein the uplink signal is a channel use beacon signal (CUBS).

35. The method of claim 24, wherein the joint control channel is associated with an indication for the UE to transmit a same transport block over each of the multiple uplink subframes designated for the variable TTI transmission.

36. The method of claim 35, wherein the same transport block includes one or more of:

uplink control signals and uplink data signals.

37. An apparatus configured for wireless communication, comprising:

means for receiving, from a base station and over one or more downlink subframes, a joint control channel, for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier, with control information;

means for receiving, from the base station, an individual control channel with additional control information;

means for determining whether the apparatus received the individual control channel without previously successfully receiving the joint control channel; and

means for performing an action when the apparatus received the individual control channel without previously successfully receiving the joint control channel.

38. The apparatus of claim 37, wherein the one or more downlink subframes begin on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

39. The apparatus of claim 37, further comprising:

means for monitoring the joint control channel over the one or more downlink subframes for uplink grants identified for the apparatus.

40. The apparatus of claim 37, wherein a size of the joint control channel is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.

41. A computer program product for wireless communications in a wireless network, comprising:

a non-transitory computer-readable medium having program code recorded thereon, the program code including;

program code for causing a user equipment (UE) to receive, from a base station and over one or more downlink subframes, a joint control channel, for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier, with control information;

program code for causing the UE to receive an individual control channel with additional control information;

program code for causing the UE to determine whether the UE received the individual control channel without previously successfully receiving the joint control channel; and

program code for causing the UE perform an action when the UE received the individual control channel without previously successfully receiving the joint control channel.

42. The computer program product of claim 41, wherein the one or more downlink subframes begin on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

43. The computer program product of claim 41, wherein the program code further includes:

program code for monitoring the joint control channel over the one or more downlink subframes for uplink grants identified for the UE.

44. The computer program product of claim 41, wherein a size of the joint control channel is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.

45. An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor,

wherein the at least one processor is configured;

to receive, from a base station and over one or more downlink subframes, a joint control channel, for variable transmission time interval (TTI) transmission over multiple uplink subframes in an unlicensed carrier, with control information;

to receive an individual control channel with additional control information;

to determine whether the apparatus received the individual control channel without previously successfully receiving the joint control channel; and

to perform an action when the apparatus received the individual control channel without previously successfully receiving the joint control channel.

46. The apparatus of claim 45, wherein the one or more downlink subframes begin on a first downlink subframe at least four subframes prior to a first scheduled uplink subframe associated with the variable TTI transmission.

47. The apparatus of claim 45, wherein the at least one processor is further configured:

to monitor the joint control channel over the one or more downlink subframes for uplink grants identified for the apparatus.

48. The apparatus of claim 45, wherein a size of the joint control channel is a fixed control size that assumes all available uplink subframes are scheduled for uplink transmission.