Reference signal (RS) configuration and transmission from serving and neighbor cell for mobility
According to certain aspects of the present disclosure, indicating which neighbor cells are synchronous or asynchronous with a serving cell may allow a UE to determine whether it can derive neighbor cell RS timing based on the serving cell timing.
1. A method for wireless communications by a network entity, comprising:
determining whether one or more neighbor cells are synchronous or asynchronous with a serving cell;
providing an indication, to one or more user equipments (UEs), if one or more of the neighbor cells are synchronous or asynchronous with the serving cell;
determining configurations for transmissions of at least one type of reference signal in the neighbor cells, such that the reference signals from the neighbor cells are transmitted within a measurement window, wherein the at least one type of reference signal comprises at least one of synchronization signal (SS) or channel state information reference signal (CSI-RS); and
providing an indication of the configurations to one or more UEs, wherein at least one of the configurations for transmissions of the at least one SS or CSI-RS provided for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one SS or CSI-RS provided for neighbor cells asynchronous with the serving cell.
2. The method of claim 1 , where the network entity also provides an indication, to one or more UEs, of which neighbor cells are synchronous or asynchronous with the serving cell.
3. The method of claim 1 , wherein:
the determination of whether the one or more neighbor cells are synchronous or asynchronous with the serving cell is based on reported symbol timing differences between a serving cell and one or more neighbor cells; and
the symbol timing differences are used to determine the configurations for at least one type of reference signal transmissions in the neighbor cells.
4. The method of claim 3 , wherein the symbol timing differences are reported by one or more UEs.
5. The method of claim 1 , wherein a subset of configuration parameters for neighbor cells synchronous with the serving cell are different than those provided for neighbor cells asynchronous with the serving cell.
6. The method of claim 5 , wherein:
the subset of parameters comprises at least one of a slot offset or periodicity;
a same slot offset or periodicity is provided for neighbor cells synchronous with the serving cell; and
different slot offsets or periodicities are provided for neighbor cells asynchronous with the serving cell.
7. The method of claim 1 , wherein the configurations are determined such that reference signals (RS) from neighbor cells arrive in a same slot or mini-slot within the measurement window.
8. The method of claim 1 , wherein the configurations are determined such that reference signals (RS) from neighbor cells arrive in adjacent slots or mini-slots within the measurement window.
9. A method for wireless communications by a user equipment (UE), comprising:
receiving an indication that one or more neighbor cells are synchronous or asynchronous with a serving cell of the UE;
based on the indication, performing at least one type of reference signal measurement in cells that are synchronous with the serving cell differently than in cells that are asynchronous with the serving cell, wherein the at least one type of reference signal measurement comprises at least one of synchronization signal (SS) measurement or channel state information reference signal (CSI-RS) measurement; and
obtaining configurations for transmissions of the at least one of SS or CSI-RS, wherein the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells asynchronous with the serving cell.
10. The method of claim 9 , further comprising receiving an indication of which neighbor cells are synchronous or asynchronous with the serving cell.
11. The method of claim 9 , wherein:
the UE is configured to perform CSI-RS measurements in cells synchronous with the serving cell without detecting SS; and
the UE is configured to detect SS in cells asynchronous with the serving cell before performing CSI-RS measurements in those cells.
12. The method of claim 9 , wherein:
the UE is configured to detect neighbor cells based on CSI-RS in cells synchronous with serving cell; and
the UE is configured to detect neighbor cells based on SS in cells asynchronous with the serving cell.
13. The method of claim 12 , wherein the UE is further configured to decode a physical broadcast channel (PBCH) in cells asynchronous with the serving cell before performing CSI-RS measurements in those cells.
14. The method of claim 9 , further comprising:
obtaining CSI-RS configuration information for a plurality of neighbor cells; and
waking up to measure CSI-RS in the neighbor cells within a measurement window determined based on the configuration information.
15. The method of claim 9 , wherein the UE is configured to determine whether to receive the CSI-RS with directional or omni-directional antenna configuration, based on the configuration information.
16. An apparatus for wireless communications by a network entity, comprising:
means for determining, whether one or more neighbor cells are synchronous or asynchronous with a serving cell;
means for providing an indication, to one or more user equipments (UEs), if one or more of the neighbor cells are synchronous or asynchronous with the serving cell;
means for determining configurations for transmissions at least one type of reference signal in the neighbor cells, such that the reference signals from the neighbor cells are transmitted within a measurement window, wherein the at least one type of reference signal comprises at least one of synchronization signal (SS) or channel state information reference signal (CSI-RS); and
means for providing an indication of the configurations to one or more UEs, wherein the configurations for transmissions of the at least one SS or CSI-RS provided for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one of SS or CSI-RS provided for neighbor cells asynchronous with the serving cell.
17. The apparatus of claim 16 , further comprising means for providing an indication, to one or more UEs, of which neighbor cells are synchronous or asynchronous with the serving cell.
18. The apparatus of claim 16 , wherein:
the determination of whether the one or more neighbor cells are synchronous or asynchronous with the serving cell is based on reported symbol timing differences between a serving cell and one or more neighbor cells; and
the symbol timing differences are used to determine the configurations for at least one type of reference signal transmissions in the neighbor cells.
19. The apparatus of claim 16 , wherein the symbol timing differences are reported by one or more UEs.
20. The apparatus of claim 16 , wherein a subset of configuration parameters for neighbor cells synchronous with the serving cell are different than those provided for neighbor cells asynchronous with the serving cell.
21. The apparatus of claim 20 , wherein:
the subset of parameters comprises at least one of a slot offset or periodicity;
a same slot offset or periodicity is provided for neighbor cells synchronous with the serving cell; and
different slot offsets or periodicities are provided for neighbor cells asynchronous with the serving cell.
22. The apparatus of claim 16 , wherein the configurations are determined such that reference signals (RS) from neighbor cells arrive in a same slot or mini-slot within the measurement window.
23. The apparatus of claim 16 , wherein the configurations are determined such that reference signals (RS) from neighbor cells arrive in adjacent slots or mini-slots within the measurement window.
24. An apparatus for wireless communications by a user equipment (UE), comprising:
means for receiving an indication if one or more neighbor cells are synchronous or asynchronous with a serving cell of the UE;
means for performing, based on the indication, at least one type of reference signal measurement in cells that are synchronous with the serving cell differently than in cells that are asynchronous with the serving cell, wherein the at least one type of reference signal comprises at least one of synchronization signal (SS) or channel state information reference signal (CSI-RS); and
means for obtaining configurations for transmissions of the at least one of SS or CSI-RS, wherein the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells asynchronous with the serving cell.
25. The apparatus of claim 24 , further comprising receiving an indication of which neighbor cells are synchronous or asynchronous with the serving cell.
26. The apparatus of claim 24 , further comprising:
means for performing CSI-RS measurements in cells synchronous with the serving cell without detecting SS; and
the UE is configured to detect SS in cells asynchronous with the serving cell before performing CSI-RS measurements in those cells.
27. The apparatus of claim 24 , further comprising:
means for detecting neighbor cells based on CSI-RS in cells synchronous with serving cell; and
means for detecting neighbor cells based on SS in cells asynchronous with the serving cell.
28. The apparatus of claim 24 , wherein the UE is further configured to decode a physical broadcast channel (PBCH) in cells asynchronous with the serving cell before performing CSI-RS measurements in those cells.
29. The apparatus of claim 24 , further comprising:
means for obtaining CSI-RS configuration information for a plurality of neighbor cells; and
means for waking up to measure CSI-RS in the neighbor cells within a measurement window determined based on the configuration information.
30. The apparatus of claim 24 , wherein the UE is configured to determine whether to receive the CSI-RS with directional or omni-directional antenna configuration, based on the configuration information.
31. A non-transitory computer readable medium having instructions stored thereon for:
determining whether one or more neighbor cells are synchronous or asynchronous with a serving cell;
providing an indication, to one or more user equipments (UEs), if one or more of the neighbor cells are synchronous or asynchronous with the serving cell;
determining configurations for transmissions of at least one type of reference signal in the neighbor cells, such that the reference signals from the neighbor cells are transmitted within a measurement window, wherein the at least one type of reference signal comprises at least one of synchronization signals (SS) or channel state information reference signal (CSI-RS); and
providing an indication of the configurations to one or more UEs, wherein the configurations for transmissions of the at least one of SS or CSI-RS provided for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one of SS or CSI-RS provided for neighbor cells asynchronous with the serving cell.
32. A non-transitory computer readable medium having instructions stored thereon for:
receiving an indication if neighbor cells are synchronous or asynchronous with a serving cell of a user equipment (UE);
based on the indication, performing at least one type of reference signal measurement in cells that are synchronous with the serving cell differently than in cells that are asynchronous with the serving cell, wherein the at least one type of reference signal comprises at least one of synchronization signal (SS) or channel state information reference signal (CSI-RS); and
obtaining configurations for transmissions of the at least one of SS or CSI-RS wherein the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells asynchronous with the serving cell.
33. An apparatus for wireless communications by a network entity, comprising:
at least one processor configured to,
determine whether one or more neighbor cells are synchronous or asynchronous with a serving cell;
provide an indication, to one or more user equipments (UEs), if neighbor cells are synchronous or asynchronous with the serving cell;
determine configurations for transmissions of at least one type of reference signal transmissions in the neighbor cells, such that the reference signals from the neighbor cells are transmitted within a measurement window, wherein the at least one type of reference signal comprises at least one of synchronization signals (SS) or channel state information reference signal (CSI-RS); and
provide an indication of the configurations to one or more UEs, wherein the configurations for transmissions of the at least one of SS or CSI-RS provided for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one of SS or CSI-RS provided for neighbor cells asynchronous with the serving cell; and
a memory coupled with the at least one processor.
34. An apparatus for wireless communications by a user equipment (UE), comprising:
a receiver configured to receive an indication if neighbor cells are synchronous or asynchronous with a serving cell of the UE; and
at least one processor configured to:
perform, based on the indication, performing at least one type of reference signal measurement in cells that are synchronous with the serving cell differently than in cells that are asynchronous with the serving cell, wherein the at least one type of reference signal comprises at least one of synchronization signals (SS) or channel state information reference signal (CSI-RS); and
obtain configurations for transmissions of the at least one of SS or CSI-RS, wherein the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells synchronous with the serving cell are different than the configurations for transmissions of the at least one of SS or CSI-RS obtained for neighbor cells asynchronous with the serving cell.