Methods and apparatus for beam search and tracking in mm-wave access systems
A method, an apparatus, and a computer program product for operating a user equipment (UE) are provided. The apparatus determines a first coarse set of beamforming paths between the UE and a first millimeter wave base station (mmW-BS), receives on a first set of narrow beamforming paths close to a first beamforming path within the first coarse set of beamforming paths, requests the first mmW-BS to transmit on a second set of narrow beamforming paths close to a second beamforming path within the first coarse set of beamforming paths when a signal quality of the first beamforming path and the first set of narrow beamforming paths are less than a first threshold, and communicates through one of the second beamforming path or a path within the second set of narrow beamforming paths.
1. A method of wireless communication for a user equipment (UE), comprising:
determining a first coarse set of beamforming paths between the UE and a first millimeter wave base station (mmW-BS);
selecting a first beamforming path and a second beamforming path within the first coarse set of beamforming paths;
receiving on a first set of narrow beamforming paths close to the first beamforming path within the first coarse set of beamforming paths;
determining to associate with the first mmW-BS based on the receiving on the first set of narrow beamforming paths;
requesting, based on the determining to associate with the first mmW-BS, the first mmW-BS to transmit on a second set of narrow beamforming paths close to the second beamforming path within the first coarse set of beamforming paths when a signal quality of the first beamforming path and the first set of narrow beamforming paths are less than a first threshold; and
communicating through one of the second beamforming path or a path within the second set of narrow beamforming paths.
2. The method of claim 1 , further comprising:
determining a second coarse set of beamforming paths between the UE and a second mmW-BS;
requesting the second mmW-BS to transmit on a third set of narrow beamforming paths close to a third beamforming path within the second coarse set of beamforming paths when a signal quality of all selected beamforming paths corresponding to the first mmW-BS are less than a second threshold;
requesting the first mmW-BS to refrain from signaling on any selected beamforming paths; and
requesting the second mmW-BS to communicate through one of the third set of narrow beamforming paths.
3. The method of claim 1 , wherein the first beamforming path has a highest signal quality of beamforming paths in the first coarse set of beamforming paths.
4. The method of claim 2 , further comprising selecting at least a third or fourth beamforming path within the second coarse set of beamforming paths.
5. The method of claim 1 , further comprising: transmitting a message that indicates a signal strength for one of the second beamforming path or a path within the second set of narrow beamforming paths.
6. A user equipment (UE) for wireless communication, comprising:
means for determining a first coarse set of beamforming paths between the UE and a first millimeter wave base station (mmW-BS);
means for selecting a first beamforming path and a second beamforming path within the first coarse set of beamforming paths;
means for receiving on a first set of narrow beamforming paths close to the first beamforming path within the first coarse set of beamforming paths;
means for determining to associated with the first mmW-BS based on the receiving on the first set of narrow beamforming paths;
means for requesting, based on the determining to associate with the first mmW-BS, the first mmW-BS to transmit on a second set of narrow beamforming paths close to the second beamforming path within the first coarse set of beamforming paths when a signal quality of the first beamforming path and the first set of narrow beamforming paths are less than a first threshold; and
means for communicating through one of the second beamforming path or a path within the second set of narrow beamforming paths.
7. The UE of claim 6 , further comprising:
means for determining a second coarse set of beamforming paths between the UE and a second mmW-BS;
means for requesting the second mmW-BS to transmit on a third set of narrow beamforming paths close to a third beamforming path within the second coarse set of beamforming paths when a signal quality of all selected beamforming paths corresponding to the first mmW-BS are less than a second threshold;
means for requesting the first mmW-BS to refrain from signaling on any selected beamforming paths; and
means for requesting the second mmW-BS to communicate through one of the third set of narrow beamforming paths.
8. The UE of claim 6 , wherein the first beamforming path has a highest signal quality of beamforming paths in the first coarse set of beamforming paths.
9. The UE of claim 7 , further comprising means for selecting at least a third or fourth beamforming path within the second coarse set of beamforming paths.
10. The UE of claim 6 , further comprising: means for transmitting a message that indicates a signal strength for one of the second beamforming path or a path within the second set of narrow beamforming paths.
11. A user equipment (UE) for wireless communication, comprising:
a memory; and
at least one processor coupled to the memory and configured to:
determine a first coarse set of beamforming paths between the UE and a first millimeter wave base station (mmW-BS);
select a first beamforming path and a second beamforming path within the first coarse set of beamforming paths;
receive on a first set of narrow beamforming paths close to the first beamforming path within the first coarse set of beamforming paths;
determine to associate with the first mmW-BS based on the reception on the first set of narrow beamforming paths;
request, based on the determination to associated with the first mmW-BS, the first mmW-BS to transmit on a second set of narrow beamforming paths close to the second beamforming path within the first coarse set of beamforming paths when a signal quality of the first beamforming path and the first set of narrow beamforming paths are less than a first threshold; and
communicate through one of the second beamforming path or a path within the second set of narrow beamforming paths.
12. The UE of claim 11 , wherein the at least one processor is further configured to:
determine a second coarse set of beamforming paths between the UE and a second mmW-BS;
request the second mmW-BS to transmit on a third set of narrow beamforming paths close to a third beamforming path within the second coarse set of beamforming paths when a signal quality of all selected beamforming paths corresponding to the first mmW-BS are less than a second threshold;
request the first mmW-BS to refrain from signaling on any selected beamforming paths; and
request the second mmW-BS to communicate through one of the third set of narrow beamforming paths.
13. The UE of claim 11 , wherein the first beamforming path has a highest signal quality of beamforming paths in the first coarse set of beamforming paths.
14. The UE of claim 12 , wherein the at least one processor is further configured to select at least a third or fourth beamforming path within the second coarse set of beamforming paths.
15. The UE of claim 11 , wherein the at least one processor is further configured to transmit a message that indicates a signal strength for one of the second beamforming path or a path within the second set of narrow beamforming paths.
16. A non-transitory computer-readable medium storing computer-executable code, comprising code to:
determine a first coarse set of beamforming paths between the UE and a first millimeter wave base station (mmW-BS);
select a first beamforming path and a second beamforming path within the first coarse set of beamforming paths;
receive on a first set of narrow beamforming paths close to a first beamforming path within the first coarse set of beamforming paths;
determining to associate with the first mmW-BS based on the reception on the first set of narrow beamforming paths
request, based on the determination to associate, the first mmW-BS to transmit on a second set of narrow beamforming paths close to a second beamforming path within the first coarse set of beamforming paths when a signal quality of the first beamforming path and the first set of narrow beamforming paths are less than a first threshold, the direction index associated with the second set of narrow beamforming paths close to the second beamforming path; and
communicate through one of the second beamforming path or a path within the second set of narrow beamforming paths.
17. The computer-readable medium of claim 16 , further comprising code to:
determine a second coarse set of beamforming paths between the UE and a second mmW-BS;
request the second mmW-BS to transmit on a third set of narrow beamforming paths close to a third beamforming path within the second coarse set of beamforming paths when a signal quality of all selected beamforming paths corresponding to the first mmW-BS are less than a second threshold;
request the first mmW-BS to refrain from signaling on any selected beamforming paths; and
request the second mmW-BS to communicate through one of the third set of narrow beamforming paths.
18. The computer-readable medium of claim 16 , wherein the first beamforming path has a highest signal quality of beamforming paths in the first coarse set of beamforming paths.
19. The computer-readable medium of claim 17 , further comprising code to select at least a third or fourth beamforming path within the second coarse set of beamforming paths.
20. The computer-readable medium of claim 16 , further comprising code to transmit a message that indicates a signal strength for one of the second beamforming path or a path within the second set of narrow beamforming paths.