nrCSIRSMeasurements

CSI-RS-based physical layer measurements

Since R2022b

Syntax

meas = nrCSIRSMeasurements(carrier,csirs,grid)

meas = nrCSIRSMeasurements(___,EnablePhaseCorrection=phasecorrection)

Description

meas = nrCSIRSMeasurements(carrier,csirs,grid) returns physical layer measurements meas for a channel state information reference signal (CSI-RS), as defined in TS 38.215 Sections 5.1.2 and 5.1.4 [1]. The returned structure meas contains the reference signal received power (RSRP), received signal strength indicator (RSSI), and reference signal received quality (RSRQ). The input carrier specifies carrier configuration parameters for a specific OFDM numerology. The input csirs specifies CSI-RS resource configuration parameters for one or more zero-power (ZP) or non-zero-power (NZP) CSI-RS resources. The input grid specifies a carrier resource array.

meas = nrCSIRSMeasurements(___,EnablePhaseCorrection=phasecorrection) also specifies if phase correction is enabled or disabled in the CSI-RS measurements, in addition to the input arguments in the previous syntax. (since R2025a)

Examples

Perform CSI-RS Measurements

Create a carrier configuration object with default properties.

carrier = nrCarrierConfig;

Create a CSI-RS configuration object. Set the row number to 1 and the frequency density to 3.

csirs = nrCSIRSConfig;
csirs.RowNumber = 1;
csirs.Density = 'three';

Generate CSI-RS symbols and indices for the specified configurations. Map the symbols to the slot grid.

ind = nrCSIRSIndices(carrier,csirs);
sym = nrCSIRS(carrier,csirs);

Initialize the carrier resource grid for one slot.

ports = max(csirs.NumCSIRSPorts);
txGrid = nrResourceGrid(carrier,ports);
txGrid(ind) = sym;

Perform OFDM modulation.

txWaveform = nrOFDMModulate(carrier,txGrid);

Apply two different levels of power scaling to the transmitted waveform.

EsdBm1 = -50;
rxWaveform1 = txWaveform * sqrt(10^((EsdBm1-30)/10));
EsdBm2 = -10;
rxWaveform2 = txWaveform * sqrt(10^((EsdBm2-30)/10));

Perform OFDM demodulation on the two received waveforms.

rxGrid1 = nrOFDMDemodulate(carrier,rxWaveform1);
rxGrid2 = nrOFDMDemodulate(carrier,rxWaveform2);

Perform CSI-RS measurements on the two received resource grids.

meas1 = nrCSIRSMeasurements(carrier,csirs,rxGrid1)

meas1 = struct with fields:
    RSRPPerAntenna: -50
    RSSIPerAntenna: -28.0688
    RSRQPerAntenna: -4.7712

meas2 = nrCSIRSMeasurements(carrier,csirs,rxGrid2)

meas2 = struct with fields:
    RSRPPerAntenna: -10.0000
    RSSIPerAntenna: 11.9312
    RSRQPerAntenna: -4.7712

Input Arguments

carrier — Carrier configuration parameters

nrCarrierConfig object

Carrier configuration parameters for a specific OFDM numerology, specified as an nrCarrierConfig object. This function uses only these properties of the nrCarrierConfig object.

• SubcarrierSpacing

• CyclicPrefix

• NSizeGrid

• NStartGrid

• NSlot

• NFrame

csirs — CSI-RS resource configuration parameters

nrCSIRSConfig object

CSI-RS resource configuration parameters, specified as an nrCSIRSConfig object. This function uses only these properties of the nrCSIRSConfig object.

• CSIRSType

• CSIRSPeriod

• RowNumber

• Density

• SymbolLocations

• SubcarrierLocations

• NumRB

• RBOffset

• NID

grid — Carrier resource array

complex-valued array

Carrier resource array, specified as a complex-valued array of size K-by-N-by-R.

• K is the number of subcarriers.

• N is the number of OFDM symbols.

• R is the number of receive antennas.

Data Types: single | double
Complex Number Support: Yes

phasecorrection — Enable phase correction

0 or false (default) | 1 or true

Enable phase correction, specified as one of these logical values:

• 0 (false) — Disable phase correction.

• 1 (true) — Enable phase correction. When you enable phase correction, the function handles timing offsets due to synchronization errors and frequency selective channels in the received waveform.

Data Types: logical | double
Complex Number Support: Yes

Output Arguments

meas — CSI-RS-based physical layer measurements

structure

CSI-RS-based physical layer measurements, returned as a structure containing these fields.

Field	Value	Description
RSRPPerAntenna	Real-valued matrix	Matrix of RSRP values in dBm relative to 1 milliwatt in 1 ohm
RSSIPerAntenna	Real-valued matrix	Matrix of RSSI values in dBm relative to 1 milliwatt in 1 ohm
RSRQPerAntenna	Real-valued matrix	Matrix of RSRQ values in dB

The rows of these matrices correspond to receive antennas. The columns correspond to the CSI-RS resources specified in the input csirs.

Data Types: struct

References

[1] 3GPP TS 38.215. “NR; Physical layer measurements.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2022b

R2025a: Enable phase correction in CSI-RS measurements

Use the EnablePhaseCorrection name-value argument to enable phase correction in the CSI-RS measurements. When you enable phase correction, the function handles timing offsets due to synchronization errors and frequency selective channels in the received waveform.