Description
Conducted Reference Sensitivity power level (PREFSENS) is a critical performance metric defined in 3GPP specifications for both User Equipment (UE) and base station (gNB, eNB, NodeB) receivers. It quantifies the receiver's ability to detect and demodulate weak signals. Technically, PREFSENS is the minimum average power received at the antenna connector (conducted) of the device under test, under specified reference conditions, for which a defined minimum throughput or maximum block error rate (BLER) is achieved. It is measured in dBm. For example, for a UE, the test involves receiving a specific reference measurement channel (e.g., a QPSK-modulated signal with a low code rate) at the PREFSENS power level, and the UE must achieve a throughput equal to or greater than 95% of the maximum possible throughput for that channel.
The measurement setup for PREFSENS is highly controlled. The signal is injected directly at the antenna connector via a cable (conducted testing), eliminating variations from over-the-air propagation. The test uses a defined reference channel with a specific bandwidth, modulation, and coding scheme (typically the most robust one, like QPSK with a low code rate). Additive White Gaussian Noise (AWGN) is added to the signal to create a specific signal-to-noise ratio (SNR) condition corresponding to the target BLER. The receiver's performance is then evaluated. The value of PREFSENS is influenced by the receiver's noise figure, the implementation loss of its baseband processing, and the thermal noise floor, which itself depends on the channel bandwidth (kTB).
PREFSENS is not a single value but is specified per operating band, channel bandwidth, and for different receiver types (e.g., diversity vs. non-diversity). In base station specifications, it is a key parameter for determining cell coverage, especially the uplink coverage limit. For network planning, the link budget calculation uses the base station's PREFSENS (as the receiver sensitivity) and the UE's maximum transmit power to determine the maximum allowable path loss. For UE conformance testing, meeting the PREFSENS requirement ensures the device has a sufficiently sensitive receiver to operate at the cell edge under normal network conditions. It is a foundational test that validates the basic RF performance of the device before more complex tests like adjacent channel selectivity or blocking are performed.
Purpose & Motivation
PREFSENS was standardized to provide an objective, repeatable, and universally comparable metric for the most fundamental capability of a radio receiver: hearing weak signals. Its existence solves the problem of defining a common benchmark for receiver sensitivity across all vendors and device models, ensuring a baseline level of network performance and user experience. Without such a standardized parameter, devices with poor sensitivity could degrade overall network performance by requiring higher transmit power from other ends of the link or failing to maintain connections at the cell edge.
Historically, as cellular technologies evolved from GSM to UMTS, LTE, and NR, the definition and test methodology for reference sensitivity were refined to account for wider bandwidths, new modulation schemes, and MIMO. Its introduction and continuous evolution address the need for accurate network planning. Engineers rely on the guaranteed PREFSENS values published in specifications to calculate realistic cell coverage areas and ensure network deployments meet service continuity targets. It also serves as a critical gatekeeper in type approval and conformance testing, preventing sub-standard devices from entering the market, which protects network integrity and ensures fair competition among device manufacturers based on verifiable performance criteria.
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (79 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
Studied in Rel-8, normative work from Rel-15.
In Release 15, the primary introduction for the "PREFSENS" (Conducted reference Sensitivity power level) function was not a new definition but a series of corrections and clarifications to existing definitions and test procedures. These included specific corrections to the definition of OTA (Over-The-Air) reference sensitivity and improvements to the polarization wording for OTA reference sensitivity measurements. Additionally, the release consolidated numerous updates to base station performance requirements in TS 38.104, which encompassed receiver sensitivity and other related RF conformance tests.
- CR to TS 37.105 - polarisation wording improvements for OTA s reference sensitivity TS 37.105CR0118
- Correction to definition of OTA reference sensitivity TS 37.105CR0123
- Correction to TDD OFF power requirement TS 37.105CR0124
- CR to TS 37.145-2: Corrections on OTA Transmit ON/OFF power TS 37.145CR0042
- CR to TS 37.145-2 - polarisation wording improvements for OTA reference sensitivity TS 37.145CR0068
- Correction to definition of OTA reference sensitivity TS 37.145CR0073
+ 19 more changes
In Release 16, the PREFSENS function saw clarifications and corrections to its testing procedures, particularly for New Radio (NR). Key updates included corrections to the interference level for the receiver dynamic range requirement and the implementation of modulation fallback procedures for total power dynamic range testing, as detailed in updates to TS 37.145-2 and TS 38.104. These changes refined the reference sensitivity power level verification for both conducted and Over-The-Air (OTA) testing scenarios.
- CR to TS 37.141 with addition of reference to data content for test models TS 37.141CR0884
- CR to TS 37.141: Correction of references for NB-IoT testing TS 37.141CR0899
- CR to TS 37.145-2 with addition of reference to data content for test models TS 37.145CR0169
- CR Modulation fallback for total power dynamic range in 37.145-2 clause 6.4.4.4.2.4 TS 37.145CR0210
- CR to 37.145-2: Correction on interference level of receiver dynamic range requirement TS 37.145CR0226
- CR to TS 37.145-2: internal TR references corrections (wrt. TR 37.941 for OTA BS testing), Rel-16 TS 37.145CR0228
+ 6 more changes
In Release 17, the updates to the "PREFSENS" function primarily involved corrections to technical reports (TR 38.852 and TR 38.853) for FRMCS deployment, specifically addressing n100 and n101 frequency aspects and their related output power limits. These changes were made to align with corrected references to the EU Decision. The core specification for conducted reference sensitivity power level testing itself, including its defined test system uncertainty of ± 0.7 dB, remained unchanged from the detailed procedures in the grounding context.
- CR to TS 38.104 on reference to FRCs TS 38.104CR0411
- Correction to IAB-MT timing reference point in TS 38.174 TS 38.174CR0042
- (NR_RAIL_EU_1900MHz_TDD-Core) CR to TR 38.852 on correction of reference to EU Decision TS 38.852CR0007
- (NR_RAIL_EU_1900MHz_TDD-Core) CR to TR 38.852: Corrections on FRMCS n101 deployment aspects and related output power limits, Rel-17 TS 38.852CR0008
- (NR_RAIL_EU_900MHz-Core) CR to TR 38.853 on correction of reference to EU Decision TS 38.853CR0007
- (NR_RAIL_EU_900MHz-Core) CR to TR 38.853: Corrections on FRMCS n100 deployment aspects and related output power limits, Rel-17 TS 38.853CR0008
In Release 18, the key update for the PREFSENS function was the correction of the test model for total power dynamic range requirements, ensuring accurate measurement of the difference between maximum and minimum total power. This work was part of broader refinements to transmitter testing, including corrections to base station output power and transmitter OFF power for specific bands. The release also involved general maintenance, such as the removal of references to empty annexes and updates to normative references.
- Adds reference for additional spurious emission levels for Band 54 TS 36.104CR4964
- Adds reference for additional spurious emission levels for Band 54 TS 36.141CR1345
- CR to 36.181: Test model correction for total power dynamic range requirements TS 36.181CR0004
- Adds reference for additional spurious emission levels for Band 54 TS 37.104CR0975
- (RInImp9-Rfmulti) Correction of reference to Suspended version of ITU-R SM.329 Recommendation TS 37.104CR1024
- (AAS_BS_LTE_UTRA-Core) Correction of reference to Suspended version of ITU-R SM.329 Recommendation TS 37.105CR0297
+ 21 more changes
In Release 19, the key update for the PREFSENS function was a correction to the reference sensitivity levels requirement for base stations that support NB-IoT operation in NR in-band specifically for a 3 MHz channel bandwidth. This change, detailed in a CR for TS 38.104, ensures the sensitivity power level requirements are accurately applied to this narrowband operation scenario. No other specific changes to the conducted reference sensitivity power level function are indicated by the provided CR titles.
- CR to TS 38.141-2 on clarification of LP-WUS power boosting TS 38.141CR0674
- (FS_NR_IMT_4400_7125_14800MHz) CR to TS 38.922 on transmission power control model TS 38.922CR0006
- CR to 37.105 on correcting OTA Total power dynamic range TS 37.105CR0319
- CR to TS 38.104: Transmit power for 3MHz CBW in band n100 TS 38.104CR0696
- (NR_FR1_lessthan_5MHz_BW-Core)CR for TS38.104, Correction on reference sensitivity levels requirement apply to BS that supports NB-IoT operation in NR in-band for 3 MHz channel bandwidth TS 38.104CR0739
- Correct Annex references in TC 8.2.6 TS 38.141CR0695
+ 3 more changes
Explore further
Broader topics and technologies where PREFSENS plays a role.
Defining Specifications
3GPP specifications that define or reference PREFSENS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 25.141 vj00 | UTRA FDD Base Station RF Conformance Testing | Rel-19 |
| TS 36.104 vj10 | Base Station (BS) radio transmission and reception | Rel-19 |
| TS 36.111 vj00 | LMU Requirements for UTDOA Positioning | Rel-19 |
| TS 36.141 vj00 | E-UTRA BS Conformance Testing | Rel-19 |
| TS 36.181 vj30 | E-UTRA RF Test Methods for Satellite Access Node | Rel-19 |
| TS 36.755 vf00 | US 600 MHz LTE Band 71 Technical Report | Rel-15 |
| TS 36.758 vf00 | LTE TDD Band 52 for Africa 3300-3400MHz | Rel-15 |
| TS 36.790 vf00 | LAA/eLAA for CBRS 3.5GHz Band in US | Rel-15 |
| TS 37.104 vj10 | MSR Base Station RF Characteristics | Rel-19 |
| TS 37.105 vj10 | AAS Base Station Transmission & Reception Requirements | Rel-19 |
| TS 37.141 vj10 | RF Test Methods for Multi-Standard Radio Base Stations | Rel-19 |
| TS 37.145 vj10 | AAS Base Station Conducted Conformance Testing | Rel-19 |
| TS 37.802 va10 | MSR BS RF Requirements for Non-Contiguous Spectrum | Rel-10 |
| TS 37.812 vb30 | Multi-band Multi-standard Radio BS Requirements | Rel-11 |
| TR 37.900 vj00 | Multi-Standard Radio (MSR) Base Station Requirements | Rel-19 |
| TS 38.104 vj20 | NR Base Station RF Requirements | Rel-19 |
| TS 38.141 vj20 | NR Base Station RF Conformance Testing Part 1 | Rel-19 |
| TS 38.174 vj10 | NR Integrated Access and Backhaul Radio Spec | Rel-19 |
| TS 38.176 vj20 | IAB Conformance Testing Specification | Rel-19 |
| TS 38.191 vj00 | NR Ambient IoT RF Characteristics | Rel-19 |
| TS 38.194 vj00 | Ambient IoT Base Station RF Spec | Rel-19 |
| TS 38.817 | 3GPP TR 38.817 | Rel-8 |
| TR 38.852 vh50 | 1900MHz NR band for European Rail Mobile Radio | Rel-17 |
| TR 38.853 vh50 | 900MHz NR Band for European Rail Mobile Radio | Rel-17 |
| TR 38.892 vi00 | Technical Report | Rel-18 |
| TR 38.922 vj20 | Study on IMT Parameters for NR in Higher Bands | Rel-19 |