Calculation of downlink positioning reference signal (PRS) symbol duration for PRS buffering purposes
Disclosed are techniques for wireless communication. In an aspect, a user equipment (UE) receives at least one positioning reference signal (PRS) resource from a reference transmission-reception point (TRP) and one or more neighboring TRPs, and processes the at least one PRS resource during a time window, wherein a length of the time window is less than or equal to an integer number of orthogonal frequency division multiplexing (OFDM) symbols of the at least one PRS resource that the UE is capable of processing, buffering, or both within the time window.
1. A method of wireless communication performed by a user equipment (UE), comprising:
receiving at least one positioning reference signal (PRS) resource from a reference transmission-reception point (TRP) and one or more neighboring TRPs; and
processing the at least one PRS resource during a time window, wherein a length of the time window is less than or equal to an integer number of orthogonal frequency division multiplexing (OFDM) symbols of the at least one PRS resource that the UE is capable of processing, buffering, or both within the time window, and wherein the length of the time window is based on a numerology of the at least one PRS resource and a smallest interval of the integer number of OFDM symbols for the numerology within a slot that covers a union of potential PRS symbols.
2. The method of claim 1 , wherein the integer number of OFDM symbols is determined based on a positioning frequency layer of the at least one PRS resource.
3. The method of claim 1 , wherein the time window is calculated as:
K
=
∑
s
∈
S
K
S
K
S
=
T
S
e
n
d
-
T
S
s
t
a
r
t
,
where S is a set of slots within a periodicity of PRS in a positioning frequency layer that contains potential PRS, μ is a numerology of PRS resources in the positioning frequency layer, and [T S start , T S end ] is an interval of the integer number of OFDM symbols for the numerology μ within slot s that covers the union of potential PRS symbols.
4. The method of claim 3 , wherein the set of slots is determined based on an expected reference signal time difference (RSTD) parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a PRS symbol occupancy within slot s.
5. The method of claim 3 , wherein the interval of the integer number of OFDM symbols for the numerology μ is based on an expected RSTD parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a PRS symbol occupancy within slot s.
6. The method of claim 3 , wherein a potential PRS comprises a PRS that is expected to be received within a duration of symbols based on an expected RSTD parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a PRS symbol occupancy within slot s.
7. The method of claim 1 , further comprising:
determining a time-domain search window of a PRS resource j of the at least one PRS resource as S j =[T start j , T end j ], where:
for a PRS resource from a neighboring TRP of the one or more neighboring TRPs, [T start j , T end j ] is a smallest interval of the integer number of OFDM symbols for a numerology μ of a positioning frequency layer that includes an interval based on an expected RSTD parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a configured PRS symbol occupancy of a slot, and
for a PRS resource from the reference TRP, [T start j , T end j ] is a smallest interval of the integer number of OFDM symbols for the numerology μ of the positioning frequency layer that includes an interval determined by the configured PRS symbol occupancy of the slot.
8. The method of claim 7 , wherein the integer number of OFDM symbols is a union of time-domain search windows across all resources of a positioning frequency layer.
9. The method of claim 1 , wherein, based on a slot containing any potential PRS symbols, all symbols of the slot are included in the integer number of OFDM symbols.
10. The method of claim 1 , wherein, for a slot that contains two or more disjoint intervals with potential PRS symbols, the integer number of OFDM symbols comprises a union of a duration from a first symbol of the slot to a last symbol of a first PRS resource expected to be received during the slot and a duration from a second symbol of the slot during which a first symbol of a second PRS resource is expected to be received to a last symbol of the slot.
11. The method of claim 1 , wherein, for a slot that does not contain two or more disjoint intervals with potential PRS symbols, the integer number of OFDM symbols comprises a first symbol of the slot during which PRS are expected to be received to a last symbol of the slot during which PRS are expected to be received.
12. The method of claim 1 , further comprising:
transmitting, to a location server, an indication of the integer number of OFDM symbols as a capability of the UE.
13. The method of claim 1 , further comprising:
transmitting, to a location server, an indication of whether the UE is capable of symbol-level or slot-level PRS buffering.
14. A user equipment (UE), comprising:
a memory;
a transceiver; and
a processor communicatively coupled to the memory and the transceiver, the processor configured to:
receive, via the transceiver, at least one positioning reference signal (PRS) resource from a reference transmission-reception point (TRP) and one or more neighboring TRPs; and
process the at least one PRS resource during a time window, wherein a length of the time window is less than or equal to an integer number of orthogonal frequency division multiplexing (OFDM) symbols of the at least one PRS resource that the UE is capable of processing, buffering, or both within the time window, and wherein the length of the time window is based on a numerology of the at least one PRS resource and a smallest interval of the integer number of OFDM symbols for the numerology within a slot that covers a union of potential PRS symbols.
15. The UE of claim 14 , wherein the integer number of OFDM symbols is determined based on a positioning frequency layer of the at least one PRS resource.
16. The UE of claim 14 , wherein the time window is calculated as:
K
=
∑
s
∈
S
K
S
K
S
=
T
S
e
n
d
-
T
S
s
t
a
r
t
,
where S is a set of slots within a periodicity of PRS in a positioning frequency layer that contains potential PRS, μ is a numerology of PRS resources in the positioning frequency layer, and [T S start , T S end ] is an interval of the integer number of OFDM symbols for the numerology p within slot s that covers the union of potential PRS symbols.
17. The UE of claim 16 , wherein the set of slots is determined based on an expected reference signal time difference (RSTD) parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a PRS symbol occupancy within slot s.
18. The UE of claim 16 , wherein the interval of the integer number of OFDM symbols for the numerology μ is based on an expected RSTD parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a PRS symbol occupancy within slot s.
19. The UE of claim 16 , wherein a potential PRS comprises a PRS that is expected to be received within a duration of symbols based on an expected RSTD parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a PRS symbol occupancy within slot s.
20. The UE of claim 14 , wherein the processor is further configured to:
determine a time-domain search window of a PRS resource j of the at least one PRS resource as S j =[T start j , T end j ], where:
for a PRS resource from a neighboring TRP of the one or more neighboring TRPs, [T start j , T end j ] is a smallest interval of the integer number of OFDM symbols for a numerology μ of a positioning frequency layer that includes an interval based on an expected RSTD parameter and an expected RSTD uncertainty parameter for the one or more neighboring TRPs, and a configured PRS symbol occupancy of a slot, and
for a PRS resource from the reference TRP, [T start j , T end j ] is a smallest interval of the integer number of OFDM symbols for the numerology μ of the positioning frequency layer that includes an interval determined by the configured PRS symbol occupancy of the slot.
21. The UE of claim 20 , wherein the integer number of OFDM symbols is a union of time-domain search windows across all resources of a positioning frequency layer.
22. The UE of claim 14 , wherein, based on a slot containing any potential PRS symbols, all symbols of the slot are included in the integer number of OFDM symbols.
23. The UE of claim 14 , wherein, for a slot that contains two or more disjoint intervals with potential PRS symbols, the integer number of OFDM symbols comprises a union of a duration from a first symbol of the slot to a last symbol of a first PRS resource expected to be received during the slot and a duration from a second symbol of the slot during which a first symbol of a second PRS resource is expected to be received to a last symbol of the slot.
24. The UE of claim 14 , wherein, for a slot that does not contain two or more disjoint intervals with potential PRS symbols, the integer number of OFDM symbols comprises a first symbol of the slot during which PRS are expected to be received to a last symbol of the slot during which PRS are expected to be received.
25. The UE of claim 14 , wherein the processor is further configured to:
cause the transceiver to transmit, to a location server, an indication of the integer number of OFDM symbols as a capability of the UE.
26. The UE of claim 14 , wherein the processor is further configured to:
cause the transceiver to transmit, to a location server, an indication of whether the UE is capable of symbol-level or slot-level PRS buffering.
27. A user equipment (UE), comprising:
means for receiving at least one positioning reference signal (PRS) resource from a reference transmission-reception point (TRP) and one or more neighboring TRPs; and
means for processing the at least one PRS resource during a time window, wherein a length of the time window is less than or equal to an integer number of orthogonal frequency division multiplexing (OFDM) symbols of the at least one PRS resource that the UE is capable of processing, buffering, or both within the time window, and wherein the length of the time window is based on a numerology of the at least one PRS resource and a smallest interval of the integer number of OFDM symbols for the numerology within a slot that covers a union of potential PRS symbols.
28. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by a user equipment (UE), cause the UE to:
receive at least one positioning reference signal (PRS) resource from a reference transmission-reception point (TRP) and one or more neighboring TRPs; and
process the at least one PRS resource during a time window, wherein a length of the time window is less than or equal to an integer number of orthogonal frequency division multiplexing (OFDM) symbols of the at least one PRS resource that the UE is capable of processing, buffering, or both within the time window, and wherein the length of the time window is based on a numerology of the at least one PRS resource and a smallest interval of the integer number of OFDM symbols for the numerology within a slot that covers a union of potential PRS symbols.