please fix the error for Index exceeds matrix dimensions.

% Parameters
M = 16; % QAM modulation order
k = log2(M); % Number of bits per symbol

% UFMC system parameters
N = 128; % Number of subcarriers
L = 4; % Number of subcarriers per data block
alpha = 0.5:0.1:1.5; % Roll-off factor range
EbNo = 10; % Energy per bit to noise power spectral density ratio (dB)

% Generate random bits
numBits = N * k; % Total number of bits
data = randi([0 1], numBits, 1); % Random binary data

% Preallocate BER arrays
berKaiser = zeros(size(alpha));
berDolphChebyshev = zeros(size(alpha));

% Perform BER simulation for different roll-off factors
for i = 1:length(alpha)
    % QAM modulation
    qamData = qammod(data, M);
    
    % UFMC modulation with Kaiser filter
    ufmcDataKaiser = ufmcKyModulation(qamData, N, L, alpha(i), 'kaiser');
    
    % UFMC modulation with Dolph-Chebyshev filter
    ufmcDataDolphChebyshev = ufmcchModulation(qamData, N, L, alpha(i), 'dolphchebyshev');
    
    % Add Rayleigh fading channel
    h = (randn(128, length(ufmcDataKaiser)) + 1i * randn(128, length(ufmcDataKaiser))) / sqrt(2);
    receivedSignalKaiser = ufmcDataKaiser .* h;
    receivedSignalDolphChebyshev = ufmcDataDolphChebyshev .* h;
    
    % AWGN channel
    snr = EbNo + 10 * log10(k); % Convert EbNo to SNR
    receivedSignalKaiser = awgn(receivedSignalKaiser, snr, 'measured');
    receivedSignalDolphChebyshev = awgn(receivedSignalDolphChebyshev, snr, 'measured');
    
    % UFMC demodulation
    demodulatedDataKaiser = ufmcKyDemodulation(receivedSignalKaiser, N, L, alpha(i), 'kaiser');
    demodulatedDataDolphChebyshev = ufmcchDemodulation(receivedSignalDolphChebyshev, N, L, alpha(i), 'dolphchebyshev');
    
    % QAM demodulation
    receivedBitsKaiser = qamdemod(demodulatedDataKaiser, M);
    receivedBitsDolphChebyshev = qamdemod(demodulatedDataDolphChebyshev, M);
    
    % Calculate BER
    berKaiser(i) = biterr(data, receivedBitsKaiser) / numBits;
    berDolphChebyshev(i) = biterr(data, receivedBitsDolphChebyshev) / numBits;
end

Unrecognized function or variable 'ufmcKyModulation'.

% Plot BER results
figure;
semilogy(alpha, berKaiser, 'b-o', 'LineWidth', 1.5);
hold on;
semilogy(alpha, berDolphChebyshev, 'r-s', 'LineWidth', 1.5);
grid on;
xlabel('Roll-off Factor (\alpha)');
ylabel('Bit Error Rate (BER)');
title('BER Performance Comparison: Kaiser vs. Dolph-Chebyshev Filter (Rayleigh Fading Channel)');
legend('Kaiser Filter', 'Dolph-Chebyshev Filter');

[Image Analyst]

Looks like the error is actually "Unrecognized function or variable 'ufmcKyModulation'" If you get a different error, then give it -- ALL THE RED TEXT. Make sure the value for the index on the right side of the equal sign is not bigger than the array.

[Umeshraja]

Hi @Teshome, Attach the helper functions such as 'ufmcKyModulation' and 'ufmcKyDemodulation' to debug further