Methods and system for LBT threshold setting for directional reception and transmission

1. A method in a wireless device for determining if a channel is clear in an unlicensed band channel in a wireless network, comprising:

determining, by the wireless device, an energy detection threshold according to a maximum equivalent isotropically radiated power (EIRP) among EIRPs of one or more transmissions following a first time interval including at least one clear channel assessment (CCA) time interval, wherein an EIRP of the EIRPs is equal to a sum of antenna gain and transmit power of one of the one or more transmissions;

detecting, by the wireless device, energy along a first beamforming direction by detecting a plurality of energies each corresponding to one of a plurality of receiving directions in parallel, wherein the first beamforming direction includes the plurality of receiving directions; and

determining, by the wireless device, whether the unlicensed band channel is clear in at least the first beamforming direction according to the energy detected along the first beamforming direction and the energy detection threshold.

2. The method of claim 1 , wherein the antenna gain of the wireless device comprises an element gain and an array gain.

3. The method of claim 1 , wherein the first time interval further comprises at least one listen before talk (LBT) time interval.

4. The method of claim 1 , wherein the energy along the first beamforming direction is normalized according to antenna gain of one or more receiving antennas.

5. The method of claim 1 , the method further comprising:

determining, by the wireless device, a CCA result at each of the plurality of receiving directions, wherein the unlicensed band channel determined being clear corresponds to one or more transmission directions, and wherein each CCA result at one or more receiving directions along the one or more transmission directions is clear.

6. A wireless device, comprising:

at least one processor; and

a non-transitory computer readable storage medium storing programming, the programming including instructions that, when executed by the at least one processor, cause the wireless device to perform operations including:

determining an energy detection threshold according to a maximum equivalent isotropically radiated power (EIRP) among EIRPs of one or more transmissions following a first time interval including at least one clear channel assessment (CCA) time interval, wherein an EIRP of the EIRPs is equal to a sum of antenna gain and transmit power of one of the one or more transmissions;

detecting energy along a first beamforming direction by detecting a plurality of energies each corresponding to one of a plurality of receiving directions in parallel, wherein the first beamforming direction includes the plurality of receiving directions; and

determining whether an unlicensed band channel is clear in at least the first beamforming direction according to the energy detected along the first beamforming direction and the energy detection threshold.

7. The wireless device of claim 6 , wherein the antenna gain of the wireless device comprises an element gain and an array gain.

8. The wireless device of claim 6 , wherein the first time interval further comprises at least one listen before talk (LBT) time interval.

9. The wireless device of claim 6 , wherein the energy along the first beamforming direction is normalized according to antenna gain of one or more receiving antennas.

10. The wireless device of claim 6 , the operations further comprising:

determining, by the wireless device, a CCA result at each of the plurality of receiving directions, wherein the unlicensed band channel determined being clear corresponds to one or more transmission directions, and wherein each CCA result at one or more receiving directions along the one or more transmission directions is clear.

11. A non-transitory computer-readable medium having instructions stored thereon that, when executed by a wireless device, cause the wireless device to perform operations, the operations comprising:

determining an energy detection threshold according to a maximum equivalent isotropically radiated power (EIRP) among EIRPs of one or more transmissions following a first time interval including at least one clear channel assessment (CCA) time interval, wherein an EIRP of the EIRPs is equal to a sum of antenna gain and transmit power of one of the one or more transmissions;

detecting energy along a first beamforming direction by detecting a plurality of energies each corresponding to one of a plurality of receiving directions in parallel, wherein the first beamforming direction includes the plurality of receiving directions; and

determining whether an unlicensed band channel is clear in at least the first beamforming direction according to the energy detected along the first beamforming direction and the energy detection threshold.

12. The non-transitory computer-readable medium of claim 11 , wherein the antenna gain of the wireless device comprises an element gain and an array gain.

13. The non-transitory computer-readable medium of claim 11 , wherein the first time interval further comprises at least one listen before talk (LBT) time interval.

14. The non-transitory computer-readable medium of claim 11 , wherein the energy along the first beamforming direction is normalized according to antenna gain of one or more receiving antennas.

15. The non-transitory computer-readable medium of claim 11 , the operations further comprising:

determining, by the wireless device, a CCA result at each of the plurality of receiving directions, wherein the unlicensed band channel determined being clear corresponds to one or more transmission directions, and wherein each CCA result at one or more receiving directions along the one or more transmission directions is clear.