Techniques for scaling bandwidth of an unlicensed radio frequency spectrum band

1. A method for wireless communication, comprising:

identifying a plurality of sub-channels in an unlicensed radio frequency spectrum band;

performing a first plurality of synchronized clear channel assessment (CCA) procedures on the plurality of sub-channels based at least in part on a first CCA threshold;

determining, based at least in part on the first plurality of synchronized CCA procedures, a first subset of sub-channels of the plurality of sub-channels that are clear according to the first CCA;

performing a second plurality of concurrent CCA procedures on the first subset of sub-channels based at least in part on a second CCA threshold;

determining a plurality of clear sub-channels based at least in part on the second plurality of concurrent CCA procedures;

determining a scalable bandwidth of a carrier based at least in part on a bandwidth associated with the plurality of clear sub-channels; and

communicating, using a transceiver, over the scalable bandwidth of the carrier using the bandwidth associated with the plurality of clear sub-channels in the unlicensed radio frequency spectrum band.

2. The method of claim 1

wherein the first CCA threshold is an optimistic CCA threshold that is set

based at least in part on all of the plurality of sub-channels being scheduled for transmission.

3. The method of claim 2 ,

wherein the second CCA threshold is a redistributed CCA threshold that is set

based at least in part on all of the first subset of sub-channels being scheduled for transmission.

4. The method of claim 2 , wherein the optimistic CCA threshold is based at least in part on a power constraint for a transmission over the plurality of sub-channels.

5. The method of claim 3 , wherein the redistributed CCA threshold is based at least in part on a power constraint for a transmission over the first subset of sub-channels.

6. The method of claim 1 , wherein the second plurality of concurrent CCA procedures is a single joint CCA measuring a sum of energy across the first subset of sub-channels.

7. The method of claim 1 , further comprising:

communicating over at least one additional carrier using the unlicensed radio frequency spectrum band, and wherein a transmission power for each sub-channel of the carriers is determined based at least in part on a power constraint for the unlicensed radio frequency spectrum band.

8. The method of claim 7 , wherein the transmission power for each sub-channel is based at least in part on a number of sub-channels in the carriers.

9. The method of claim 1 , wherein a first sub-channel of the carrier is allocated a first transmission power, and at least one second sub-channel of the carrier is allocated a second transmission power, the first transmission power being different from the second transmission power.

10. The method of claim 9 , wherein the first transmission power and the second transmission power are pre-defined values.

11. The method of claim 10 , wherein a Clear channel assessment Exempt Transmission (CET) comprises the pre-defined values.

12. The method of claim 9 , wherein the first transmission power and the second transmission power are based at least in part on a desired coverage area for the first sub-channel and the at least one second sub-channel.

13. The method of claim 9 , wherein the first transmission power and the second transmission power are based at least in part on a desired capacity for the first sub-channel and the at least one second sub-channel.

14. The method of claim 9 , wherein the first transmission power and the second transmission power are based at least in part on a number of sub-channels in the carrier.

15. The method of claim 9 , further comprising:

transmitting a first reference signal on the first sub-channel; and

transmitting a second reference signal on the at least one second sub-channel, wherein a transmission power for the first reference signal is the same as a transmission power for the second reference signal.

16. The method of claim 15 , wherein the first reference signal and the second reference signal comprise extended Common Reference Signals (eCRS's).

17. The method of claim 15 , wherein the first reference signal and the second reference signal comprise Channel State Information Reference Signals (CSI-RS's).

18. The method of claim 15 , wherein the transmission powers for the first reference signal and the second reference signal are fixed values.

19. An apparatus for wireless communication, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions being executable by the processor to:

identify a plurality of sub-channels in an unlicensed radio frequency spectrum band;

performing a first plurality of synchronized clear channel assessment (CCA) procedures on the plurality of sub-channels based at least in part on a first CCA threshold;

determine, based at least in part on the first plurality of synchronized CCA procedures, a first subset of sub-channels of the plurality of sub-channels that are clear according to the first CCA;

performing a second plurality of concurrent CCA procedures on the first subset of sub-channels based at least in part on a second CCA threshold;

determining a plurality of clear sub-channels based at least in part on the second plurality of concurrent CCA procedures;

determine a scalable bandwidth of a carrier based at least in part on a bandwidth associated with the plurality of clear sub-channels; and

communicate, using a transceiver, over the scalable bandwidth of the carrier using the bandwidth associated with the plurality of clear sub-channels in the unlicensed radio frequency spectrum band.

20. The apparatus of claim 19 , wherein the instructions are executable by the processor to:

perform the first plurality of synchronized CCA procedures on the plurality of sub-channels based at least in part on an optimistic CCA threshold that is set

based at least in part on all of the plurality of sub-channels being scheduled for transmission.

21. The apparatus of claim 20 , wherein the

second CCA threshold is a redistributed CCA threshold that is set

based at least in part on all of the first subset of sub-channels being scheduled for transmission.

22. The apparatus of claim 19 , wherein resources of the plurality of clear sub-channels are addressed as one logical group.

23. The apparatus of claim 22 , wherein the plurality of clear sub-channels comprises a first sub-channel and at least one second sub-channel, the first sub-channel being non-adjacent to the at least one second sub-channel.

24. The apparatus of claim 19 , wherein the instructions are executable by the processor to:

communicate over at least one additional carrier using the unlicensed radio frequency spectrum band, and wherein a transmission power for each sub-channel of the carriers is determined based at least in part on a power constraint for the unlicensed radio frequency spectrum band.

25. The apparatus of claim 19 , wherein a first sub-channel of the carrier is allocated a first transmission power, and at least one second sub-channel of the carrier is allocated a second transmission power, the first transmission power being different from the second transmission power.

26. The apparatus of claim 25 , wherein the instructions are executable by the processor to:

transmit a first reference signal on the first sub-channel; and

transmit a second reference signal on the at least one second sub-channel, wherein a transmission power for the first reference signal is the same as a transmission power for the second reference signal.

27. An apparatus for wireless communication, comprising:

means for identifying a plurality of sub-channels in an unlicensed radio frequency spectrum band;

means for performing a first plurality of synchronized clear channel assessment (CCA) procedures on the plurality of sub-channels based at least in part on a first CCA threshold;

means for determining, based at least in part on the first plurality of synchronized CCA procedures, a first subset of sub-channels of the plurality of sub-channels that are clear according to the first CCA;

means for performing a second plurality of concurrent CCA procedures on the first subset of sub-channels based at least in part on a second CCA threshold;

means for determining a plurality of clear sub-channels based at least in part on the second plurality of concurrent CCA procedures;

means for determining a scalable bandwidth of a carrier based at least in part on a bandwidth associated with the plurality of clear sub-channels; and

means for communicating, using a transceiver, over the scalable bandwidth of the carrier using the bandwidth associated with the plurality of clear sub-channels in the unlicensed radio frequency spectrum band.

28. The apparatus of claim 27 ,

wherein the first CCA threshold is an optimistic CCA threshold that is set

based at least in part on all of the plurality of sub-channels being scheduled for transmission.

29. The apparatus of claim 28 ,

wherein the second CCA threshold is a redistributed CCA threshold that is set

based at least in part on all of the first subset of sub-channels being scheduled for transmission.

30. The apparatus of claim 27 , wherein resources of the plurality of clear sub-channels are addressed as one logical group, and wherein the plurality of clear sub-channels comprises a first sub-channel and at least one second sub-channel, the first sub-channel being non-adjacent to the at least one second sub-channel.

31. The apparatus of claim 27 , further comprising:

means for communicating over at least one additional carrier using the unlicensed radio frequency spectrum band, and wherein a transmission power for each sub-channel of the carriers is determined based at least in part on a power constraint for the unlicensed radio frequency spectrum band.

32. The apparatus of claim 27 , wherein a first sub-channel of the carrier is allocated a first transmission power, and at least one second sub-channel of the carrier is allocated a second transmission power, the first transmission power being different from the second transmission power.

33. A non-transitory computer-readable medium storing computer-executable code for wireless communication, the code executable by a processor to:

identify a plurality of sub-channels in an unlicensed radio frequency spectrum band;

performing a first plurality of synchronized clear channel assessment (CCA) procedures on the plurality of sub-channels based at least in part on a first CCA threshold;

determine, based at least in part on the first plurality of synchronized CCA procedures, a first subset of sub-channels of the plurality of sub-channels that are clear according to the first CCA;

performing a second plurality of concurrent CCA procedures on the first subset of sub-channels based at least in part on a second CCA threshold;

determining a plurality of clear sub-channels based at least in part on the second plurality of concurrent CCA procedures;

determine a scalable bandwidth of a carrier based at least in part on a bandwidth associated with the plurality of clear sub-channels; and

communicate, using a transceiver, over the scalable bandwidth of the carrier using the bandwidth associated with the plurality of clear sub-channels in the unlicensed radio frequency spectrum band.

34. The non-transitory computer-readable medium of claim 33 , wherein:

the first CCA threshold is an optimistic CCA threshold that is set;

based at least in part on all of the plurality of sub-channels being scheduled for transmission; and

the second CCA threshold is a redistributed CCA threshold that is set

based at least in part on all of the first subset of sub-channels being scheduled for transmission.

35. The non-transitory computer-readable medium of claim 33 , wherein the code is executable by the processor to:

communicate over at least one additional carrier using the unlicensed radio frequency spectrum band, and

wherein a transmission power for each sub-channel of the carriers is determined based at least in part on a power constraint for the unlicensed radio frequency spectrum band.

36. The non-transitory computer-readable medium of claim 33 , wherein a first sub-channel of the carrier is allocated a first transmission power, and at least one second sub-channel of the carrier is allocated a second transmission power, the first transmission power being different from the second transmission power.