nrPRS

Generate PRS symbols

Since R2021a

Syntax

sym = nrPRS(carrier,prs)

sym = nrPRS(carrier,prs,Name=Value)

Description

sym = nrPRS(carrier,prs) generates positioning reference signal (PRS) symbols sym, as defined in TS 38.211 Section 7.4.1.7.2 [1], for carrier configuration carrier and PRS configuration prs. The function also handles the conditions related to the mapping of PRS resources to slots, as defined in TS 38.211 Section 7.4.1.7.4.

sym = nrPRS(carrier,prs,Name=Value) specifies options by using one or more name-value arguments. For example, OutputDataType='single' sets the data type of the output symbols to single.

Examples

Generate PRS Symbols for Multiple Resources in Resource Set

Create a default carrier configuration object.

carrier = nrCarrierConfig;

Specify the extended cyclic prefix for a subcarrier spacing of 60 KHz and slot number 92.

carrier.SubcarrierSpacing = 60;
carrier.CyclicPrefix = 'extended';
carrier.NSlot = 92;

Create a default PRS configuration object.

prs = nrPRSConfig;

Set properties that are common to all PRS resources in a resource set.

prs.PRSResourceSetPeriod = [640 0];
prs.PRSResourceRepetition = 8;
prs.PRSResourceTimeGap = 4;
prs.MutingPattern1 = [1 0 0 1];
prs.MutingBitRepetition = 2;
prs.MutingPattern2 = [1 0 1 1 1 0 1 0];
prs.NumRB = 52;
prs.RBOffset = 0;
prs.CombSize = 2;

Set properties that are unique to each PRS resource in a resource set.

prs.PRSResourceOffset = [0 40 80 120];
prs.NumPRSSymbols = [6 4 12 2];
prs.SymbolStart = 0;
prs.REOffset = [0 1 0 1];
prs.NPRSID = 15;

Generate PRS symbols of single data type with a cell resource format.

sym = nrPRS(carrier,prs,'OutputDataType','single','OutputResourceFormat','cell')

sym=1×4 cell array
    {0×1 single}    {0×1 single}    {3744×1 single}    {0×1 single}

Generate PRS Symbols and Indices for Two Resources

Create a default carrier configuration object.

carrier = nrCarrierConfig;

Create a default PRS configuration object.

prs = nrPRSConfig;

Set properties related to the PRS slot configuration.

prs.PRSResourceSetPeriod = [8 0]; % Resource set periodicity of 8 slots and resource set slot offset of 0 slots
prs.PRSResourceOffset = [0 4];    % Configure two PRS resources with slot offsets 0 and 4 relative to resource set offset
prs.PRSResourceRepetition = 2;    % Repeat each PRS resource twice
prs.PRSResourceTimeGap = 1;       % Configure two PRS resource repetition indices with no time gap

Set properties related to the PRS muting configuration.

prs.MutingPattern1 = [1 1];       % Transmit all PRS resource set instances
prs.MutingBitRepetition = 1;      % One instance of a PRS resource set corresponding to a single element of MutingPattern1 binary vector
prs.MutingPattern2 = [1 0];       % Mute second repetition index of all the PRS resources within an active instance of a PRS resource set

Set properties related to the PRS time-domain allocation.

prs.NumPRSSymbols = [6 12];
prs.SymbolStart = [6 0];

Set properties related to the PRS frequency-domain allocation.

prs.NumRB = 40;
prs.RBOffset = 4;
prs.CombSize = 4;
prs.REOffset = [1 3];
prs.NPRSID = 5;       % Set PRS sequence identity

Get the number of orthogonal frequency division multiplexing (OFDM) symbols per slot.

numSymPerSlot = carrier.SymbolsPerSlot;

Set the number of slots to 20.

numSlots = 20;

Map the resource elements (RE) for both of the PRS resources on the carrier resource grid.

grid = complex(zeros(carrier.NSizeGrid*12,carrier.SymbolsPerSlot*numSlots));
for slotIdx = 0:numSlots-1
    carrier.NSlot = slotIdx;
    indCell = nrPRSIndices(carrier,prs,'OutputResourceFormat','cell');
    symCell = nrPRS(carrier,prs,'OutputResourceFormat','cell');
    slotGrid = nrResourceGrid(carrier);
    slotGrid(indCell{1}) = 70*symCell{1};                              % Resource element mapping of PRS resource 1 with some scaling for plotting purpose
    slotGrid(indCell{2}) = 250*symCell{2};                             % Resource element mapping of PRS resource 2 with some scaling for plotting purpose
    grid(:,(1:numSymPerSlot)+numSymPerSlot*slotIdx) = slotGrid;
end
figure
image(abs(grid));
axis xy;
L = line(ones(2),ones(2),'LineWidth',8);               % Generate lines
set(L,{'color'},{[0.18 0.51 0.98]; [0.96 0.95 0.11]}); % Set the colors
legend('PRS Resource 1','PRS Resource 2');             % Create legend
title('PRS Resource Elements');
xlabel('OFDM Symbols');
ylabel('Subcarriers');

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 nrCarrierConfig object properties.

• SubcarrierSpacing

• CyclicPrefix

• NSizeGrid

• NStartGrid

• NSlot

• NFrame

prs — PRS configuration parameters

nrPRSConfig object

PRS configuration parameters, specified as an nrPRSConfig object. This function uses only these nrPRSConfig object properties.

• PRSResourceSetPeriod

• PRSResourceOffset

• PRSResourceRepetition

• PRSResourceTimeGap

• MutingPattern1

• MutingBitRepetition

• MutingPattern2

• NumPRSSymbols

• SymbolStart

• NumRB

• RBOffset

• CombSize

• NPRSID

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: OutputDataType='single' sets the data type of the output symbols to single.

OutputDataType — Data type of output symbols

'double' (default) | 'single'

Data type of the output symbols, specified as 'double' or 'single'.

Data Types: char | string

OutputResourceFormat — Output format of PRS symbols

'concatenated' (default) | 'cell'

Output format of PRS symbols, specified as one of these values.

• 'concatenated' — The output sym is a single column vector containing all PRS symbols concatenated.

• 'cell' — The output sym is a cell array where each cell corresponds to a single PRS resource.

Data Types: char | string

Output Arguments

sym — PRS symbols

column vector | cell array of column vectors

PRS symbols, returned as a column vector or a cell array of column vectors. If this output is a cell array of column vectors, each cell represents the PRS symbols corresponding to each PRS resource in a PRS resource set.

Data Types: single | double
Complex Number Support: Yes

References

[1] 3GPP TS 38.211. “NR; Physical channels and modulation (Release 16).” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

The datatype input argument must be compile-time constant. For example, when specifying 'single' as the output data type, include {coder.Constant('OutputDataType'),coder.Constant('single')} in the -args value of the codegen function. For more information, see the coder.Constant (MATLAB Coder) class.

Version History

Introduced in R2021a