one error i can not solve plz solve it.

clc;

clear;

close all;

M = 16; % Number of antenna elements

L = 100; % Number of snapshots

f = 3e9; % Carrier frequency in Hz

c = 3e8; % Speed of light in m/s

lambda = c/f; % Wavelength in meters

d = lambda/2; % Element spacing in meters

k = d/lambda; % Wavenumber

thetas = [0 10]; % Angle of arrival in degrees for the first signal

thetai = [-30 30]; % Angle of arrival in degrees for the interfering signals

n = [0:M-1]';

snr = 30; % SNR in dB

inr = 10; % Interference-to-noise ratio in dB

% Uncomment one of the following lines to select the antenna array pattern

% chuang = hamming(M)';

% chuang = kaiser(M,pi)';

chuang = ones(M,1)';

vs = exp(-1j*2*pi*n*sin(thetas/180*pi)*d/lambda); % Steering vector for the desired signal

for i = 1:length(thetas)

vi = exp(-1j*2*pi*n*sin(thetai(i)/180*pi)*d/lambda); % Steering vector for the interfering signals

f_mod = 16000; % Modulation frequency in Hz

t = [0:L-1]/200;

xs = sqrt(10^(snr/10))*vs.'.*exp(1j*2*pi*f_mod*t); % Desired signal with additive noise

xi = sqrt(10^(inr/10)/2)*vi.*(randn(M,L)+1j*randn(M,L)); % Interference with additive noise

noise = (randn(M,L)+1j*randn(M,L))/sqrt(2); % Additive noise

X = xs.' + xi + noise; % Received signal with additive noise

R = X*X'/L; % Covariance matrix of the received signal

w = inv(R)*vs/(vs'*inv(R)*vs); % Optimal beamforming weight vector

w2(:,i) = w;

sita = 100*[-1:0.001:1]; % Angle of arrival for the grid search in degrees

v = exp(-1j*2*pi*k*n*sin(sita/180*pi)); % Steering vector for the grid search

B = abs(w'*v); % Beam pattern

B = 20*log10(B/max(B)); % Normalized beam pattern in dB

figure

plot(sita,B,'b');

title(['Array Pattern (M = ',num2str(M),')']);

xlabel('Angle of Arrival (degrees)');

ylabel('Normalized Power Pattern (dB)');

grid on

axis([-100 100 -70 10]);

end

% Combining the weights for the desired signal and the interfering signals

w1 = sum(w2,2);

sita = 100*[-1:0.001:1];

v = exp(-1j*2*pi*k*n*sin(sita/180*pi));

B = abs(w1'*v);

B = 20*log10(B/max(B));

figure

plot(sita,B,'b');

title(['Array Pattern (M = ',num2str(M),')']);

xlabel('Angle of Arrival (degrees)');

ylabel('Normalized Power Pattern (dB)');

grid on

axis([-100 100 -70 10]);

Answer 1

[Torsten]

If you check the sizes of vs.' and 1j*2*pi*f_mod*t

    size(vs.')
    size(1j*2*pi*f_mod*t) 

you will see that multiplication as

    xs = sqrt(10^(snr/10))*vs.'.*exp(1j*2*pi*f_mod*t); % Desired signal with additive noise

is not possible.