Can Anyone help me to solve this error?Error using * Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of rows in the second matrix. To perform elementwise multiplication, use '.

here's the full code

numAntennasTx = 256; % Number of antennasTx

numAntennasRx = 16; % Number of antennasRx

numBits = 10000000; % Number of random bits

ModulationOrder = 16; % 16QAM

snrValues = 0:5:40; % Range of SNR values

%% Generate Random Bits

bits = randi([0 1], numBits, 1);

%% Convolutional Encoding

trellis = poly2trellis(7, [171 133]); % Example trellis

codedBits = convenc(bits, trellis);

%% Modulation

mod_symbols = qammod(codedBits, ModulationOrder, 'InputType', 'bit', 'UnitAveragePower', true);

%% Ensure the number of symbols can be reshaped properly

numSymbols = length(mod_symbols);

paddingSymbols = mod(numAntennasTx - mod(numSymbols, numAntennasTx), numAntennasTx);

mod_symbols_padded = [mod_symbols; zeros(paddingSymbols, 1)];

%% Reshape modulated symbols to fit Tx antennas

mod_symbols_reshaped = reshape(mod_symbols_padded, numAntennasTx, []);

%% Precoding

H = (randn(numAntennasRx, numAntennasTx) + 1i * randn(numAntennasRx, numAntennasTx)) / sqrt(2*numAntennasRx); % Channel matrix

% Regularized Zero Forcing (RZF) Precoding

lambda = 0.01; % Regularization parameter

WRZF = (H' / (H*H' + lambda*eye(numAntennasRx)));

% Phased Zero Forcing (PZF) Precoding

angle_H = angle(H);

phase_shift = exp(-1i*angle_H);

H_pzf = H .* phase_shift;

WPZF = (H_pzf' / (H_pzf*H_pzf'));

%% Apply Precoding

precodedBitsRZF = WRZF * mod_symbols_reshaped; % precoding RZF

precodedBitsPZF = WPZF * mod_symbols_reshaped; % precoding PZF

%% Without Precoding

precodedBitsWP = mod_symbols_reshaped; % No precoding

%% OFDM Modulation with Precoding

OfdmSymbolsRZF = ifft(precodedBitsRZF, [], 2); % OFDM modulation with RZF precoding

OfdmSymbolsPZF = ifft(precodedBitsPZF, [], 2); % OFDM modulation with PZF precoding

OfdmSymbolsWP = ifft(precodedBitsWP, [], 2); % OFDM modulation without precoding

%% Channel AWGN

berRZF = zeros(1, length(snrValues)); % Initialize BER results for RZF

berPZF = zeros(1, length(snrValues)); % Initialize BER results for PZF

berWP = zeros(1, length(snrValues)); % Initialize BER results for no precoding

for i = 1:length(snrValues)

snr = snrValues(i);

noiseVar = 1 / (10^(snr/10));

% Transmit through channel (AWGN) for RZF

rxSymbolsRZF = awgn(H * OfdmSymbolsRZF, snr, 'measured') + sqrt(noiseVar/2) * (randn(size(OfdmSymbolsRZF)) + 1i * randn(size(OfdmSymbolsRZF)));

% Transmit through channel (AWGN) for PZF

rxSymbolsPZF = awgn(H * OfdmSymbolsPZF, snr, 'measured') + sqrt(noiseVar/2) * (randn(size(OfdmSymbolsPZF)) + 1i * randn(size(OfdmSymbolsPZF)));

% Transmit through channel (AWGN) without precoding

rxSymbolsWP = awgn(H * OfdmSymbolsWP, snr, 'measured') + sqrt(noiseVar/2) * (randn(size(OfdmSymbolsWP)) + 1i * randn(size(OfdmSymbolsWP)));

%% OFDM Demodulation

% Serial to Parallel Conversion

receivedSymbolsRZFSerial = reshape(rxSymbolsRZF, [], numAntennasRx).'; % Serial to parallel conversion

receivedSymbolsPZFSerial = reshape(rxSymbolsPZF, [], numAntennasRx).'; % Serial to parallel conversion

receivedSymbolsWPSerial = reshape(rxSymbolsWP, [], numAntennasRx).'; % Serial to parallel conversion

% Perform OFDM demodulation for RZF

rxSymbolsIFFTRZF = fft(receivedSymbolsRZFSerial, [], 2); % FFT

% Perform OFDM demodulation for PZF

rxSymbolsIFFTPZF = fft(receivedSymbolsPZFSerial, [], 2); % FFT

% Perform OFDM demodulation for no precoding

rxSymbolsIFFTWP = fft(receivedSymbolsWPSerial, [], 2); % FFT

%% Parallel to Serial Conversion

rxSymbolsDemod_RZF = reshape(rxSymbolsIFFTRZF.', [], 1); % Parallel to serial conversion

rxSymbolsDemod_PZF = reshape(rxSymbolsIFFTPZF.', [], 1); % Parallel to serial conversion

rxSymbolsDemod_WP = reshape(rxSymbolsIFFTWP.', [], 1); % Parallel to serial conversion

% Remove the padded symbols before demodulation

rxSymbolsDemod_RZF = rxSymbolsDemod_RZF(1:end-paddingSymbols);

rxSymbolsDemod_PZF = rxSymbolsDemod_PZF(1:end-paddingSymbols);

rxSymbolsDemod_WP = rxSymbolsDemod_WP(1:end-paddingSymbols);

% QAM demodulation

demodBitsRZF = qamdemod(rxSymbolsDemod_RZF, ModulationOrder, 'OutputType', 'bit', 'UnitAveragePower', true);

demodBitsPZF = qamdemod(rxSymbolsDemod_PZF, ModulationOrder, 'OutputType', 'bit', 'UnitAveragePower', true);

demodBitsWP = qamdemod(rxSymbolsDemod_WP, ModulationOrder, 'OutputType', 'bit', 'UnitAveragePower', true);

% Calculate the Bit Error Rate (BER)

berRZF(i) = sum(demodBitsRZF ~= codedBits(1:end-paddingSymbols)) / numBits;

berPZF(i) = sum(demodBitsPZF ~= codedBits(1:end-paddingSymbols)) / numBits;

berWP(i) = sum(demodBitsWP ~= codedBits(1:end-paddingSymbols)) / numBits;

end

%% Display Results

fprintf('Bit Error Rate (RZF Precoding):\n');

disp(berRZF);

fprintf('Bit Error Rate (PZF Precoding):\n');

disp(berPZF);

fprintf('Bit Error Rate (Without Precoding):\n');

disp(berWP);

%% Plotting the results

figure;

semilogy(snrValues, berRZF, 'bs-', 'LineWidth', 2);

hold on;

semilogy(snrValues, berPZF, 'gs-', 'LineWidth', 2);

semilogy(snrValues, berWP, 'rs-', 'LineWidth', 2);

xlabel('SNR (dB)');

ylabel('Bit Error Rate (BER)');

legend('RZF Precoding', 'PZF Precoding', 'Without Precoding');

title('Massive MIMO 256x16 Antennas with RZF and PZF Precoding');

grid on;

[Gita]

here's the error

Error using *

Incorrect dimensions for matrix multiplication. Check that the number of

columns in the first matrix matches the number of rows in the second matrix.

To perform elementwise multiplication, use '.*'.

Error in Main (line 39)

precodedBitsRZF = WRZF * mod_symbols_reshaped; % precoding RZF