MPSK Signal Carrier Frequency Estimation Based on Higher-Order Cyclic Spectrum

MPSK (Multiple Phase Shift Keying) signal is a modulation scheme that enables carrier frequency estimation through higher-order cyclic spectrum analysis. In MATLAB, the following code demonstrates how to generate and process MPSK signals with cyclic spectrum-based carrier frequency estimation:

% Parameter configuration M = 16; % Modulation order (16-PSK) Fs = 1000; % Sampling frequency (Hz) T = 1/Fs; % Sampling interval fc = 100; % Carrier frequency (Hz) Ts = 1/fc; % Carrier period t = 0:T:Ts-T; % Time vector for one carrier cycle % MPSK signal generation data = randi([0, M-1], 1, length(t)); % Random symbol generation symbols = exp(1j*2*pi*data/M); % PSK constellation mapping % Carrier wave generation carrier = exp(1j*2*pi*fc*t); % Complex exponential carrier % Modulation process modulated_signal = symbols .* carrier; % Element-wise multiplication for modulation % Cyclic spectral estimation using cross-power spectral density [cycspec, freq] = cpsd(modulated_signal, modulated_signal, length(modulated_signal), length(modulated_signal)-1); % Cyclic spectrum visualization plot(freq, abs(cycspec)); % Plot magnitude spectrum xlabel('Frequency (Hz)'); ylabel('Magnitude'); title('Cyclic Spectrum of MPSK Signal');

This implementation demonstrates the complete workflow for MPSK signal processing in MATLAB. The code generates random symbols, maps them to PSK constellation points, modulates them onto a carrier wave, and performs cyclic spectral analysis using the cpsd function for carrier frequency estimation. The cyclic spectrum plot reveals spectral features that can be used to extract the carrier frequency component from the modulated signal.