Assistance information for beam mapping across different remote radio heads
Certain aspects of the present disclosure provide a method for wireless communications by a user equipment (UE), generally including receiving assistance information, from a network entity, indicating a mapping between beams across different remote radio heads (RRHs) and using the assistance information to perform beam management when the UE is moving from the coverage area of one RRH to the coverage area of another RRH.
1. An apparatus for wireless communications at a user equipment (UE), comprising:
one or more memories comprising instructions; and
one or more processors configured to execute the instructions and cause the apparatus to:
receive assistance information, from a network entity, indicating a mapping between beams across different remote radio heads (RRHs), wherein the mapping indicates one or more beams from a first RRH within a same direction as one or more beams from a second RRH, and wherein the assistance information further indicates additional information comprising a distance between projections of adjacent beam peaks; and
use the assistance information to perform beam management when the UE is moving from a coverage area of one RRH to a coverage area of another RRH.
2. The apparatus of claim 1 , wherein at least some of the RRHs are in different cells.
3. The apparatus of claim 1 , wherein the assistance information indicates a first set of beam indexes that belong to the first RRH and a second set of beam indexes that belong to the second RRH.
4. The apparatus of claim 1 , wherein the assistance information indicates the mapping between the beams across the different RRHs that have same or similar quasi co-location (QCL) receive spatial filter properties.
5. The apparatus of claim 4 , wherein the assistance information indicates beam management reference signals on the different RRHs having the same or similar QCL receive spatial filter properties.
6. The apparatus of claim 5 , wherein the beam management reference signals comprise at least one of synchronization signal blocks (SSBs), Channel State Information Reference Signals (CSI-RS), or reference signals for radio resource management (RRM) measurement procedures.
7. The apparatus of claim 4 , wherein the same or similar QCL receive spatial filter properties comprise beam peak direction differences within a threshold value of degrees.
8. The apparatus of claim 1 , wherein the assistance information is provided as a mapping table indicating mappings of beams of the first RRH to beams of the second RRH.
9. The apparatus of claim 1 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to use the assistance information to reduce latency for at least one of: beam discovery, neighboring cell detection, beam refinement, or beam switching.
10. The apparatus of claim 1 , wherein the UE is located in or on a vehicle traveling a known route.
11. The apparatus of claim 10 , wherein the UE is located in or on a high speed train (HST) and the RRHs are deployed along a track on which the HST moves.
12. The apparatus of claim 11 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to receive the additional information further comprising beam peak direction angles relative to the track and a beam-width projection on the track in which radiated power is within a threshold value.
13. The apparatus of claim 1 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to derive beam switch timing based on the additional information.
14. The apparatus of claim 1 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to:
provide an indication of a speed at which the UE is traveling; and
receive signaling for beam switching with switching timing derived based on the indicated speed.
15. The apparatus of claim 1 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to receive the assistance information:
via a radio resource control (RRC) message signaling an initial mapping configuration; and
via a medium access control (MAC) control element (MAC-CE) command signaling an update of the mapping in each RRH.
16. An apparatus for wireless communications at a network entity, comprising:
one or more memories comprising instructions; and
one or more processors configured to execute the instructions and cause the apparatus to:
determine beams across different remote radio heads (RRHs) that have same or similar quasi co-location (QCL) properties; and
transmit assistance information to a user equipment (UE) indicating a mapping between beams across the different RRHs that have same or similar QCL properties, wherein the mapping indicates one or more beams from a first RRH within a same direction as one or more beams from a second RRH, and wherein the assistance information further indicates additional information comprising a distance between projections of adjacent beam peaks.
17. The apparatus of claim 16 , wherein at least some of the RRHs are in different cells.
18. The apparatus of claim 16 , wherein the assistance information indicates a first set of beam indexes that belong to the first RRH and a second set of beam indexes that belong to a second RRH.
19. The apparatus of claim 16 , wherein the assistance information indicates the mapping between the beams across the different RRHs that have same or similar quasi co-location (QCL) receive spatial filter properties.
20. The apparatus of claim 16 , wherein the assistance information indicates beam management reference signals on the different RRHs having the same or similar QCL receive spatial filter properties.
21. The apparatus of claim 20 , wherein the beam management reference signals comprise at least one of synchronization signal blocks (SSBs), Channel State Information Reference Signals (CSI-RS), or reference signals for radio resource management (RRM) measurement procedures.
22. The apparatus of claim 19 , wherein the same or similar QCL receive spatial filter properties comprise beam peak direction differences within a threshold value of degrees.
23. The apparatus of claim 16 , wherein the assistance information is provided as a mapping table indicating mappings of beams of the first RRH to beams of the second RRH.
24. The apparatus of claim 16 , wherein the UE is located in or on a vehicle traveling a known route.
25. The apparatus of claim 24 , wherein the UE is located in or on a high speed train (HST) and the RRHs are deployed along a track on which the HST moves.
26. The apparatus of claim 25 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to transmit, to the UE, the additional information further comprising beam peak direction angles relative to the track and a beam-width projection on the track in which radiated power is within a threshold value.
27. The apparatus of claim 16 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to:
receive, from the UE, an indication of a speed at which the UE is traveling; and
transmit, to the UE, signaling for beam switching with switching timing derived based on the indicated speed.
28. The apparatus of claim 16 , wherein the one or more processors are configured to execute the instructions and cause the apparatus to transmit the assistance information:
via a radio resource control (RRC) message signaling an initial mapping configuration; and
via a medium access control (MAC) control element (MAC-CE) command signaling an update of the mapping in each RRH.
29. A method for wireless communications at a user equipment (UE), comprising:
receiving assistance information, from a network entity, indicating a mapping between beams across different remote radio heads (RRHs), wherein the mapping indicates one or more beams from a first RRH within a same direction as one or more beams from a second RRH, and wherein the assistance information further indicates additional information comprising a distance between projections of adjacent beam peaks; and
using the assistance information to perform beam management when the UE is moving from a coverage area of one RRH to a coverage area of another RRH.
30. A method for wireless communications at a network entity, comprising:
determining beams across different remote radio heads (RRHs) that have same or similar quasi co-location (QCL) properties; and
transmitting assistance information to a user equipment (UE) indicating a mapping between the beams across the different RRHs that have same or similar QCL properties, wherein the mapping indicates one or more beams from a first RRH within a same direction as one or more beams from a second RRH, and wherein the assistance information further indicates additional information comprising a distance between projections of adjacent beam peaks.