5G NR RSRP, RSRQ, and SINR Measurements Explained

This page provides a comprehensive explanation of the RSRP, RSRQ, and SINR measurements used in 5G NR (New Radio) systems. We’ll define these key performance indicators (KPIs) and discuss their application in 5G NR. Furthermore, we will explore the RRC (Radio Resource Control) Information Elements (IEs) that carry these measurements. Specifically, we will define SS-RSRP, CSI-RSRP, SS-RSRQ, CSI-RSRQ, SS-SINR, and CSI-SINR.

Introduction

• In LTE (Long-Term Evolution), RSRP (Reference Signal Received Power) and RSRQ (Reference Signal Received Quality) are associated with CRS (Cell-specific Reference Signals).
• In 5G NR, CRS is not used. Instead, SS (Synchronization Signal) and CSI (Channel State Information) are employed.
• Consequently, RSRP, RSRQ, and SINR (Signal-to-Interference-plus-Noise Ratio) are associated with SS and CSI.
• These measurements are defined for both FR1 (Frequency Range 1) and FR2 (Frequency Range 2).
  • FR1 spans from 450 MHz to 6000 MHz.
  • FR2 spans from 24250 MHz to 52600 MHz.
  • FR1 uses subcarrier spacings of 15/30/60 kHz, while FR2 uses 60/120 kHz.
  • FR1 supports transmission bandwidths from 5 MHz (minimum) to 100 MHz (maximum).
  • FR2 supports 50 MHz (minimum), 100 MHz, 200 MHz, and 400 MHz (maximum).

5G NR RSRP: SS-RSRP and CSI-RSRP

SS-RSRP (SS Reference Signal Received Power)

• Definition: SS-RSRP stands for Synchronization Signal Reference Signal Received Power.
• It’s defined as the linear average of the power contributions (in Watts) of the resource elements carrying secondary synchronization signals (SSS).
• The measurement time resources for SS-RSRP are confined within the SS/PBCH Block Measurement Time Configuration (SMTC) window duration.
• Frequency Range 1 (FR1): The reference point for SS-RSRP is the antenna connector of the UE (User Equipment).
• Frequency Range 2 (FR2): SS-RSRP is measured based on the combined signal from antenna elements corresponding to a given receiver branch.

SS-RSRP is used in the following scenarios:

• If SS-RSRP is used for L1-RSRP: RRC_CONNECTED intra-frequency.
• Otherwise: RRC_IDLE intra-frequency, RRC_IDLE inter-frequency, RRC_INACTIVE intra-frequency, RRC_INACTIVE inter-frequency, RRC_CONNECTED intra-frequency, RRC_CONNECTED inter-frequency.

CSI-RSRP (CSI Reference Signal Received Power)

• Definition: CSI-RSRP stands for Channel State Information Reference Signal Received Power.
• It’s defined as the linear average of the power contributions (in Watts) of the resource elements carrying CSI reference signals configured for RSRP measurements.
• For CSI-RSRP determination, CSI reference signals are transmitted on antenna port 3000 (as per TS 38.211).
• Frequency Range 1 (FR1): The reference point for CSI-RSRP is the antenna connector of the UE.
• Frequency Range 2 (FR2): CSI-RSRP is measured based on the combined signal from antenna elements corresponding to a given receiver branch.

CSI-RSRP is used in the following scenarios:

• If CSI-RSRP is used for L1-RSRP: RRC_CONNECTED intra-frequency.
• Otherwise: RRC_CONNECTED intra-frequency, RRC_CONNECTED inter-frequency.

5G NR RSRQ: SS-RSRQ and CSI-RSRQ

SS-RSRQ (SS Reference Signal Received Quality)

• Definition: SS-RSRQ stands for Synchronization Signal Reference Signal Received Quality.
• It’s defined as the ratio of N x SS-RSRP / NR carrier RSSI.
  • N refers to the number of resource blocks in the NR carrier RSSI measurement bandwidth.
  • The measurements in the numerator (N x SS-RSRP) and denominator (NR carrier RSSI) must be made over the same set of resource blocks (RBs).
• NR carrier RSSI (Received Signal Strength Indicator) is the linear average of the total received power (Watts). It’s observed only in specific OFDM symbols within the measurement time resources, across the measurement bandwidth, over N resource blocks from all sources.
  • These sources include co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc.

SS-RSRQ is used in the following scenarios:

RRC_IDLE intra-frequency, RRC_IDLE inter-frequency, RRC_INACTIVE intra-frequency, RRC_INACTIVE inter-frequency, RRC_CONNECTED intra-frequency, RRC_CONNECTED inter-frequency.

CSI-RSRQ (CSI Reference Signal Received Quality)

• Definition: CSI-RSRQ stands for Channel State Information Reference Signal Received Quality.
• It’s defined as the ratio of N x CSI-RSRP to CSI-RSSI.
  • N is the number of RBs in the CSI-RSSI measurement bandwidth.
  • The measurements in the numerator (N x CSI-RSRP) and denominator (CSI-RSSI) must be made over the same set of resource blocks (RBs).
• CSI Received Signal Strength Indicator (CSI-RSSI) is the linear average of the total received power (Watts).
• It’s observed only in OFDM symbols within the measurement time resource(s), across the measurement bandwidth, over N resource blocks from all sources.
  • These sources include co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc.
• The measurement time resources for CSI-RSSI correspond to OFDM symbols containing configured CSI-RS occasions.

CSI-RSRQ is used in the following scenarios:

RRC_CONNECTED intra-frequency, RRC_CONNECTED inter-frequency.

5G NR SINR: SS-SINR and CSI-SINR

SS-SINR (SS Signal-to-Interference-plus-Noise Ratio)

• Definition: SS-SINR stands for Synchronization Signal Signal-to-Interference-plus-Noise Ratio.
• It’s defined as the linear average of the power contribution (in Watts) of the resource elements carrying secondary synchronization signals divided by the linear average of the noise and interference power contribution (in Watts) over the resource elements carrying secondary synchronization signals within the same frequency bandwidth.

SS-SINR is used in the following scenarios:

RRC_CONNECTED intra-frequency, RRC_CONNECTED inter-frequency.

CSI-SINR (CSI Signal-to-Interference-plus-Noise Ratio)

• Definition: CSI-SINR stands for Channel State Information Signal-to-Interference-plus-Noise Ratio.
• It’s defined as the linear average of the power contribution (in Watts) of the resource elements carrying CSI reference signals divided by the linear average of the noise and interference power contribution (in Watts) over the resource elements carrying CSI reference signals within the same frequency bandwidth.

CSI-SINR is used in the following scenarios:

RRC_CONNECTED intra-frequency, RRC_CONNECTED inter-frequency.

Absolute Accuracy SS-RSRP Intra Frequency measurement

The requirements for absolute accuracy of SS-RSRP apply to a cell on the same carrier frequency as used by the serving cell.

Relative Accuracy SS-RSRP Intra Frequency measurement

The relative accuracy of SS-RSRP is defined as SS-RSRP from one cell in comparison to SS_RSRP measured on another cell as the same frequency.

Relative Accuracy SS-RSRP Intra Frequency measurement

The relative accuracy of SS-RSRP is defined as SS-RSRP from one cell in comparison to SS_RSRP measured on another cell as the same frequency.

Absolute Accuracy SS-RSRP Inter Frequency measurement

The requirements for absolute accuracy of SS-RSRO apply to a cell which has different carrier frequency from the serving cell.

References

• 3GPP TS 38.215, NR; Physical layer measurements
• 3GPP TS 38.331, NR; Radio Resource Control (RRC); Protocol specification
• 3GPP TS 38.133, NR; Requirements for support of radio resource management

RRC IEs carrying RSRP, RSRQ and SINR

The following PDF document outlines the RRC IEs (Information Elements) that carry the RSRP, RSRQ, and SINR measurements utilized in the 5G NR system.

• SRS stands for Sounding Reference signal.
• It is used for UL channel sounding.
• In contrast to LTE, it is configured specific to UE.
• In time domain, it spans 1/2/4 consecutive symbols which are mapped within last six symbols of the slot.
• Multiple SRS symbols allow coverage extension and increased sounding capacity.
• The design of SRS and its frequency hopping mechanism is same as used in LTE.

Following tables are as per 3GPP TS 38.133 V15.2.0 specifications released in June 2018. The values in the tables are subjected to change as per latest releases from 3GPP.