Adaptively using subframes for radar detection in unlicensed spectrum

1. A method of communications, comprising:

scheduling a first set of subframes in a frame duration for traffic based at least in part on a first configuration for communications in an unlicensed frequency band, wherein the first set of subframes in the first configuration comprises two sets of two consecutive subframes corresponding to downlink traffic periods;

scheduling, based at least in part on the first configuration, a second set of subframes in the frame duration for detection of a primary user of the unlicensed frequency band, wherein the second set of subframes in the first configuration comprises two sets of three consecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band;

comparing an amount of traffic to a scheduler threshold;

identifying a second configuration for communications in the unlicensed frequency band when the amount of traffic exceeds the scheduler threshold, wherein the second configuration for communications is identified based on a type of primary user being detected; and

adjusting a number of subframes in the first and second set of subframes based on the second configuration for communications.

2. The method of claim 1 , wherein adjusting the number of subframes in the first and second set of subframes based at least in part on the second configuration comprises:

increasing the number of subframes in the first set; and

decreasing the number of subframes in the second set.

3. The method of claim 2 , wherein the first set of subframes in the second configuration comprises two sets of three consecutive subframes corresponding to downlink traffic periods, and wherein the second set of subframes in the second configuration comprises two sets of two consecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band.

4. The method of claim 2 , wherein the first set of subframes in the second configuration comprises two sets of two consecutive subframes and two sets of nonconsecutive subframes corresponding to downlink traffic periods, and wherein the second set of subframes in the second configuration comprises four sets of nonconsecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band.

5. The method of claim 1 , wherein comparing the amount of traffic to the scheduler threshold comprises comparing the amount of traffic scheduled for transmission on the first set of subframes to the scheduler threshold.

6. The method of claim 5 , further comprising establishing the scheduler threshold based at least in part on a full utilization of the first set of subframes and a scheduled amount of traffic in a buffer.

7. The method of claim 6 , further comprising:

determining that the buffer is full of traffic scheduled for transmission on the first set of subframes; and

scheduling traffic on all subframes in the frame duration in response to determining that the buffer is full of traffic scheduled for transmission on the first set of subframes.

8. The method of claim 1 , wherein the subframes in each of the first and second set of subframes are configured as multi-cast broadcast single-frequency network (MBSFN) subframes.

9. The method of claim 1 , wherein the unlicensed frequency band is an Unlicensed National Information Infrastructure (U-NII) radio band.

10. The method of claim 1 , wherein the second set of subframes is configured to schedule data only for one or more common reference signal (CRS) symbols.

11. A computer-readable medium storing computer executable code for communication, comprising code to:

schedule a first set of subframes in a frame duration for traffic based at least in part on a first configuration for communications in an unlicensed frequency band, wherein the first set of subframes in the first configuration comprises two sets of two consecutive subframes corresponding to downlink traffic periods;

schedule, based at least in part on the first configuration, a second set of subframes in the frame duration for detection of a primary user of the unlicensed frequency band, wherein the second set of subframes in the first configuration comprises two sets of three consecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band;

compare an amount of traffic to a scheduler threshold;

identify a second configuration for communications in the unlicensed frequency band when the amount of traffic exceeds the scheduler threshold, wherein the second configuration for communications is identified based on a type of primary user being detected; and

adjust a number of subframes in the first and second set of subframes based on the second configuration for communications.

12. An apparatus for communication, comprising:

means for scheduling a first set of subframes in a frame duration for traffic based at least in part on a first configuration for communications in an unlicensed frequency band, wherein the first set of subframes in the first configuration comprises two sets of two consecutive subframes corresponding to downlink traffic periods;

means for scheduling, based at least in part on the first configuration, a second set of subframes in the frame duration for detection of a primary user of the unlicensed frequency band, wherein the second set of subframes in the first configuration comprises two sets of three consecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band;

means for comparing an amount of traffic to a scheduler threshold;

means for identifying a second configuration for communications in the unlicensed frequency band when the amount of traffic exceeds the scheduler threshold, wherein the second configuration for communications is identified based on a type of primary user being detected; and

means for adjusting a number of subframes in the first and second set of subframes based on the second configuration for communications.

13. An apparatus for communication, comprising:

a memory storing executable instructions; and

a processor in communication with the memory, wherein the processor is configured to execute the instructions to:

schedule a first set of subframes in a frame duration for traffic based at least in part on a first configuration for communications in an unlicensed frequency band, wherein the first set of subframes in the first configuration comprises two sets of two consecutive subframes corresponding to downlink traffic periods;

schedule, based at least in part on the first configuration, a second set of subframes in the frame duration detection of a primary user of the unlicensed frequency band, wherein the second set of subframes in the first configuration comprises two sets of three consecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band;

compare an amount of traffic to a scheduler threshold;

identify a second configuration for communications in the unlicensed frequency band when the amount of traffic exceeds the scheduler threshold, wherein the second configuration for communications is identified based on a type of primary user being detected; and

adjust a number of subframes in the first and second set of subframes based on the second configuration for communications.

14. The apparatus of claim 13 , wherein to adjust the number of subframes in the first and second set of subframes, the processor is further configured to execute the instructions to:

increase the number of subframes in the first set; and

decrease the number of subframes in the second set.

15. The apparatus of claim 14 , wherein the first set of subframes in the second configuration comprises two sets of three consecutive subframes corresponding to downlink traffic periods, and wherein the second set of subframes in the second configuration comprises two sets of two consecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band.

16. The apparatus of claim 14 , wherein the first set of subframes in the second configuration comprises two sets of two consecutive subframes and two sets of nonconsecutive subframes corresponding to downlink traffic periods, and wherein the second set of subframes in the second configuration comprises four sets of nonconsecutive subframes corresponding to gap periods for detection of the primary user of the unlicensed frequency band.

17. The apparatus of claim 13 , wherein to compare the amount of traffic to the scheduler threshold, the processor is further configured to execute the instructions to compare the amount of traffic scheduled for transmission on the first set of subframes to the scheduler threshold.

18. The apparatus of claim 17 , wherein the processor is further configured to execute the instructions to establish the scheduler threshold based at least in part on a full utilization of the first set of subframes and a scheduled amount of traffic in a buffer.

19. The apparatus of claim 18 , wherein the processor is further configured to execute the instructions to:

determine that the buffer is full of traffic scheduled for transmission on the first set of subframes; and

schedule traffic on all subframes in the frame duration in response to determining that the buffer is full of traffic scheduled for transmission on the first set of subframes.

20. The apparatus of claim 13 , wherein the subframes in each of the first and second set of subframes are configured as multi-cast broadcast single-frequency network (MBSFN) subframes.

21. The apparatus of claim 13 , wherein the unlicensed frequency band is an Unlicensed National Information Infrastructure (U-NII) radio band.

22. The apparatus of claim 13 , wherein the second set of subframes is configured to schedule data only for one or more common reference signal (CRS) symbols.