Description
SL-PRS-RSRP is a physical layer measurement defined in 3GPP specifications 37.571, 38.305, and 38.355. It quantifies the linear average power of resource elements that carry Sidelink Positioning Reference Signals (SL-PRS) within the considered measurement bandwidth. Specifically, it measures the power received from a specific transmitting UE's SL-PRS, excluding noise and interference from other sources. This measurement is performed by a receiving UE as part of sidelink positioning techniques, such as Time Difference of Arrival (TDOA) or Angle of Arrival (AoA), where accurate power estimation is critical.
The measurement procedure involves the receiving UE identifying and demodulating the SL-PRS symbols transmitted by a target UE. The SL-PRS are specifically designed sequences with good autocorrelation and cross-correlation properties, transmitted on predefined time-frequency resources. The UE measures the power over these reference signal resources, typically applying filtering and averaging to mitigate fast fading and improve measurement accuracy. The result is reported in dBm and can be used by higher-layer positioning protocols or directly in positioning algorithms.
Architecturally, SL-PRS-RSRP measurement is implemented in the UE's physical layer, with results reported to the Radio Resource Control (RRC) layer or positioning protocol layer (e.g., LPP over SL). Key components include the SL-PRS configuration (defining bandwidth, periodicity, and sequence), the measurement bandwidth, and the reporting criteria. Its role is to provide a fundamental input for path loss estimation, which is essential for range-based positioning methods. Accurate SL-PRS-RSRP measurements enable better modeling of the radio channel, improving the precision of distance estimates between UEs and enhancing overall sidelink positioning performance in applications like vehicular platooning and industrial sensor networks.
Purpose & Motivation
SL-PRS-RSRP was introduced in Release 18 to provide a standardized, accurate method for measuring received power of positioning-specific reference signals in sidelink. Prior to its definition, sidelink positioning often relied on measurements of general sidelink synchronization or demodulation reference signals, which were not optimized for positioning accuracy and could be suboptimal due to different signal characteristics and interference scenarios.
The creation of SL-PRS-RSRP was driven by the increasing demand for high-accuracy positioning in V2X and ProSe applications, such as cooperative collision avoidance and augmented reality. Previous approaches lacked dedicated power measurements for positioning signals, leading to inconsistencies and reduced positioning performance. By defining a specific RSRP measurement for SL-PRS, 3GPP ensures that positioning algorithms have reliable and consistent power metrics, enabling better path loss compensation, improved multilateration accuracy, and enhanced robustness in varying channel conditions.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (39 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the SL-PRS-RSRP function was not explicitly introduced or detailed within the provided grounding context. The context focuses on conformance testing for established positioning methods like A-GNSS and OTDOA, while the listed Change Requests pertain to general positioning architecture, measurement gaps, and signaling, not specifically to sidelink positioning reference signals. Therefore, based solely on the given materials, no new technical details for SL-PRS-RSRP in Release 15 can be described.
- Signalling between an LMF and NG-RAN node/UE TS 38.305CR0001
- Gaps for positioning measurements TS 38.305CR0002
- CR to 38.305 on use of positioning measurement gaps for subframe and slot timing detection towards E-UTRA TS 38.305CR0008
- Minor restructuring of sensor references and addition of sensor methods (IMU) TS 38.305CR0009
- Adding missing reference for autonomous and measuremnts gaps for Inter-RAT RSTD measurements TS 38.305CR0010
- Corrections for Positioning Architecture TS 38.305CR0015
In Release 16, the new SL-PRS-RSRP function was introduced as part of the broader standardization of NR positioning and sidelink positioning, specifically defined within the new Sidelink Positioning Protocol (SLPP). This addition enabled new sidelink-based positioning methods, such as SL-RTT (Sidelink Round Trip Time), for which corresponding performance test scenarios and assistance data were subsequently defined in the conformance specifications.
- Introduction of B1C signal in BDS system in A-GNSS TS 38.305CR0013
- Introduction of NR positioning TS 38.305CR0017
- Introduction of NR positioning TS 38.305CR0034
- Update B1I signal ICD file to v3.0 in BDS system in A-GNSS TS 38.305CR0024
- Corrections to NR Positioning TS 38.305CR0025
- Correction to SUPL support for NR positioning methods TS 38.305CR0028
+ 6 more changes
In Release 17, the SL-PRS-RSRP function was introduced as part of the sidelink positioning enhancements, enabling new measurement capabilities for device-to-device positioning. This addition is detailed within the new NR Sidelink Positioning Protocol (SLPP) specification. The release also included various corrections and clarifications to the overall NR positioning stage 2 descriptions to support this and other new positioning methods.
- Introduction of R17 Positioning Enhancements TS 38.305CR0086
- 38.305 CR for Positioning WI TS 38.305CR0099
- Stage 2 corrections for NR Positioning Enhancements TS 38.305CR0100
- Corrections to stage 2 descriptions for NR positioning TS 38.305CR0118
- Miscellaneous corrections for Positioning Stage2 TS 38.305CR0119
- Positioning Information Transfer TS 38.305CR0141
+ 3 more changes
In Release 18, the SL-PRS-RSRP function was introduced as part of the expanded and improved NR positioning enhancements, specifically for sidelink positioning. This new capability is defined within the NR Sidelink Positioning Protocol (SLPP) specification, enabling UEs to measure reference signal received power based on sidelink positioning reference signals. The release also included clarifications and corrections on assistance data transfer and the maximum number of participating UEs in sidelink positioning procedures.
- Introduction of 'Expanded and improved NR positioning TS 38.305CR0150
- Support of NR Positioning Enhancements TS 38.305CR0161
- Positioning restrictions for UE-to-network remote UEs [PosL2RemoteUE] TS 38.305CR0134
- Correction on support of Bluetooth positioning mode [BT-AoA-AoD] TS 38.305CR0157
- Update of stage 2 positioning information TS 38.305CR0173
- Correction on assistance data transfer in SL positioning for stage-2 TS 38.305CR0175
+ 2 more changes
In Release 19, the SL-PRS-RSRP function was introduced as a new measurement for sidelink positioning, enabling UEs to measure the power of Sidelink Positioning Reference Signals from other vehicles or devices. This addition is detailed within the NR Sidelink Positioning Protocol (SLPP) specification, providing the foundation for enhanced relative positioning in V2X and direct communication scenarios. The release also included associated conformance testing frameworks to validate this new capability.
- Introduction of AIML Positioning TS 38.305CR0190
- Corrections on AIML Positioning TS 38.305CR0197
- Corrections on LPHAP, carrier phase, bandwidth aggregation and frequency hopping for positioning (R19 Cat. A CR) TS 38.305CR0198
- Correction to Positioning activation and deactivation procedure TS 38.305CR0200
Explore further
Broader topics and technologies where SL-PRS-RSRP plays a role.
Defining Specifications
3GPP specifications that define or reference SL-PRS-RSRP, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 37.571 vj00 | UE Conformance for Positioning | Rel-19 |
| TS 38.305 vj00 | NG-RAN UE Positioning Stage 2 | Rel-19 |
| TS 38.355 vj00 | Sidelink Positioning Protocol (SLPP) | Rel-19 |