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lteULPrecode

SC-FDMA precoding

Description

example

out = lteULPrecode(in,nrb) performs SC-FDMA precoding of complex modulation symbols in for PUSCH or NPUSCH configuration with a bandwidth of nrb resource blocks.

out = lteULPrecode(in,n,resourceType) performs SC-FDMA precoding of the complex modulation symbols in for PUSCH or NPUSCH configuration with a bandwidth of n resource blocks or subcarriers.

Examples

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UL precoding is a step in the PUSCH processing chain. The chain includes scrambling, symbol mapping, UL precoding, RE mapping, and SC-FDMA modulation.

Create a UE-specific configuration structure, get PUSCH indices, and generate a bit stream sized according to configuration structure.

ue = lteRMCUL('A3-2');
[puschInd, info] = ltePUSCHIndices(ue,ue.PUSCH);
ueDim = lteULResourceGridSize(ue);
bits = randi([0,1],info.G,ue.PUSCH.NLayers);

Perform scrambling, symbol modulation, and UL precoding.

scrBits = lteULScramble(ue,bits);
symbols = lteSymbolModulate(scrBits,ue.PUSCH.Modulation);
precodedSymbols = lteULPrecode(symbols,ue.NULRB);

Generate resource mapping grid, populate the grid with the precoded symbols, and perform SC-FDMA modulation.

grid = lteULResourceGrid(ue);
grid(puschInd) = precodedSymbols;
[timeDomainSig,infoScfdma] = lteSCFDMAModulate(ue,grid);

Generate an SC-FDMA modulated waveform for a three-tone NB-IoT uplink configuration by applying the SC-FDMA processing chain, comprising symbol mapping, UL precoding, and SC-FDMA modulation.

Specify an NB-IoT configuration with ten slots and a subcarrier spacing of 15 kHz.

NSlots = 10;
ue.NBULSubcarrierSpacing = '15kHz';

Set the subcarrier locations and generate random bits for transmission.

chs.NBULSubcarrierSet = 0:2;
bits = randi([0,1],7*NSlots*length(chs.NBULSubcarrierSet)*2,1);

Perform symbol modulation and generate precoded symbols.

symbols = lteSymbolModulate(bits,'QPSK');
precodedSymbols = lteULPrecode(symbols,length(chs.NBULSubcarrierSet),'Subcarrier');

Generate the narrowband resource array

grid = repmat(lteNBResourceGrid(ue),1,NSlots);
grid(chs.NBULSubcarrierSet + 1,:) = reshape(precodedSymbols,length(chs.NBULSubcarrierSet),7*NSlots);

Generate the SC-FDMA modulated waveform for the specified configuration and display its size.

waveform = lteSCFDMAModulate(ue,chs,grid);
size(waveform)
ans = 1×2

        9600           1

Generate an SC-FDMA modulated waveform for a single-tone NB-IoT uplink configuration by applying the SC-FDMA processing chain, comprising symbol mapping, UL precoding, and SC-FDMA modulation.

Specify an NB-IoT configuration with 16 slots and a subcarrier spacing of 3.75 kHz.

NSlots = 16;
ue.NBULSubcarrierSpacing = '3.75kHz';

Specify the channel transmission configuration.

chs = struct('NULSlots',4,'NRU',1,'NRep',4,'SlotIdx',0, ...
    'Modulation','BPSK','NBULSubcarrierSet',41);

Generate random bits for transmission, perform symbol modulation, and generate precoded symbols.

bits = randi([0,1],7*NSlots*length(chs.NBULSubcarrierSet),1);
symbols = lteSymbolModulate(bits,chs.Modulation);
precodedSymbols = lteULPrecode(symbols,length(chs.NBULSubcarrierSet),'Subcarrier');

Generate the narrowband resource array

grid = repmat(lteNBResourceGrid(ue),1,NSlots);
grid(chs.NBULSubcarrierSet+1,:) = reshape(precodedSymbols,length(chs.NBULSubcarrierSet),7*NSlots);

Generate the SC-FDMA modulated waveform for the specified configuration and display its size.

waveform = lteSCFDMAModulate(ue,chs,grid);
size(waveform)
ans = 1×2

       61440           1

Input Arguments

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Complex modulation symbols, specified as an NSym-by-NL complex-valued matrix. NSym is the number of symbols and NL is the number of layers.

Data Types: double
Complex Number Support: Yes

Number of resource blocks, specified as a nonnegative integer.

Data Types: double

Number of resource blocks or subcarriers, specified as a nonnegative integer.

Dependencies

If the resourceType input is 'PRB', then n is the number of resource blocks. If the resourceType is 'Subcarrier', then n is the number of subcarriers.

Data Types: double

Resource type, specified as 'PRB' or 'Subcarrier'.

Data Types: char | string

Output Arguments

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Precoded PUSCH symbols, returned as an NSym-by-NL complex-valued matrix. NSym is the number of symbols, and NL is the number of layers.

The dimension and size of the input and output symbol matrices are the same.

Data Types: double
Complex Number Support: Yes

Introduced in R2014a