Why this code gives error?

Nc=31; N=5; M=3; K=3; tot_len=200;
array_TX =[3.5086  0    0;2.6877   2.2553    0;0.6093   3.4553    0;-1.7543   3.0385    0;-3.2970    1.2000     0;
           -3.2970   -1.2000      0;-1.7543   -3.0385         0;0.6093   -3.4553      0;2.6877   -2.2553     0];

    array_RX =[0.8507         0         0;0.2629    0.8090         0;-0.6882    0.5000         0;
               -0.6882   -0.5000         0;0.2629   -0.8090         0];
    
    DOA =[270 180  70  89  158  204  208  339  167].';
    DOD =[40  120  150  195  223  161  75  350];
    91


recvd_data = myreceived_data(Nc,N,M,K,tot_len,array_TX,DOD,array_RX,DOA);

[Walter Roberson]

myreceived_data is not a Mathworks function, but the problem is occurring inside it. We would need the code.

[Sadiq Akbar]

Thank you very much dear Walter Roberson for your response. The requirede function is as below:

%1-Received data
function recvd_data = myreceived_data(Nc,N_bar,N,M,K,tot_len,array_TX,DOD,array_RX,DOA)

recvd_data1 = zeros(N,tot_len*Nc);
shift_data = zeros(N_bar,tot_len*Nc,M,K);
for m = 1:M
    for k = 1:K
        shift_data(:,:,m,k) = circshift(data_tx_ss(:,:,m),[0,delays(m,k)]); % Shift circularly columns of matrix towards right
    end
end



for m = 1:M
    for k = 1:K
        for t = 1:tot_len
            S_TX = spv(array_TX, [DOD(k+(m-1)*K) 0]);
            S_RX = spv(array_RX, [DOA(k+(m-1)*K) 0]);
            recvd_data(:,Nc*(t-1)+1:Nc*t) = recvd_data1(:,Nc*(t-1)+1:Nc*t) + (beta(k+(m-1)*K,t)*S_RX).*(S_TX'*shift_data(:,Nc*(t-1)+1:Nc*t,m,k));% it is x(t) in eq.(6)
        end
        
    end
end


end % function end

Answer 1

[Fernando Peña]

When calling the function, you are missing the variable N_bar.

[Sadiq Akbar]

Thanks for your response dear Fernando Peña. Yes I have forgotten in writing here. N_bar=9; But thats not the reason. Even if you provide N_bar=9; to the calling function still it says:

Error using zeros

Size inputs must be scalar.

Error in myreceived_data (line 4)

recvd_data1 = zeros(N,tot_len*Nc);

[Fernando Peña]

I'll try to explain it in a clearer way:

In the line:

recvd_data = myreceived_data(Nc,N,M,K,tot_len,array_TX,DOD,array_RX,DOA);

The argument "N_bar" is not included. Then, as an argument is missing, the function is taking "array_TX" (matrix, non scalar) as the argument corresponding to "tot_len".

You should write instead:

recvd_data = myreceived_data(Nc,N_bar,N,M,K,tot_len,array_TX,DOD,array_RX,DOA);

I hope this way it's easier to understand.

[Sadiq Akbar]

Thank you very much dear Fernando Peña for your guidance. Yes, you are rigth. But why this gives error?

M=3;Nc=31; N_bar=9; N=5; M=3; K=3; tot_len=200;delays=[1 9 15;18 27 22;16 16 22];
mseq1=[1  1  1  1  1  0  0  0  1  1  0  1  1  1  0  1  0  1  0  0  0  0  1  0  0  1  0  1  1  0  0
].';
mseq2=[1  1  1  1  1  0  1  1  1  0  0  0  1  0  1  0  1  1  0  1  0  0  0  0  1  1  0  0  1  0  0
].';

recvd_data = myreceived_data(Nc,N_bar,N,M,K,tot_len,array_TX,DOD,array_RX,DOA, data_tx_ss,delays)
[cost_func]=recvd_data_preproc(M,Nc,N,N_bar,tot_len,recvd_data,mseq1,mseq2);

%2-Pre-processig the Received data
function  [cost_func]=recvd_data_preproc(M,Nc,N,N_bar,tot_len,recvd_data,mseq1,mseq2)
          %[cost_func]=recvd_data_preproc(M,Nc,N,N_bar,tot_len,recvd_data,mseq1,mseq2);

temp = mseq1;
Code_matrix = zeros(Nc,N_bar,M); % line 23 in main code
for m = 1:M %user no.
    for i = 1:N_bar % Tx antenna no.
        temp = circshift(temp,[1 0]); % shifts elements in column vector "temp" by 1 towards down
        Code_matrix(:,i,m) = xor(temp,mseq2); % code matrix (31 x 9) for each user
    end
end
Code_matrix = 1-2.*Code_matrix;

for m = 1:M
    data_tx = (randn(1,tot_len) + 1i*randn(1,tot_len))/sqrt(2); % Random row vector 1x200
    Code_mat_temp = Code_matrix(:,:,m); % 31 x 9
    shift = 0;
    for n = 1:N_bar
        data_tx_ss(n,:,m) = kron(data_tx, Code_mat_temp(:,n)');
    end
end


Code_mat_des = Code_matrix(:,:,1);

%received matrix N*Nc*L ( where L means total no. of snapshots)
recvd_3D_cube = zeros(N,Nc,tot_len);
for l = 1:tot_len-1
    startpt = (l-1)*Nc+1; % ???????
    endpt = startpt + Nc-1; % ???????
    recvd_3D_cube(:,:,l) = recvd_data(:,startpt:endpt);
end

recvd_data_preproco = zeros(N*N_bar,tot_len);

for l = 1:tot_len
    temp_mat = [];
    for m = 1:N_bar
        temp = recvd_3D_cube(:,:,l)*Code_mat_des(:,m);
        temp_mat = cat(2,temp_mat,temp); % (1st matrix then 2nd matrix in same level but cat(1,temp_mat,temp) will keep 1st matrix then 2nd matrix just below)
    end
    recvd_data_preproco(:,l) = temp_mat(:);
end


Rxx = recvd_data_preproc*recvd_data_preproc'./tot_len; % (Covariance matrix from recvd_data_preproc)
[E,D] = eig(Rxx); % (Eigen vectors matrix E and diadonal matrix D haiving eigen values on main diagonal)
[D,order] = sort(abs(diag(D)),'descend'); %(Arrange eigen values in decending order)
%%
% figure;
% plot(10*log10(D));
E = E(:,order); %(Arrange eigen vectors in same order as are eigen values)
Esig = E(:,1:2*M*K);
P_En = eye(N*N_bar) - Esig*pinv(Esig'*Esig)*Esig';

% figure      
dod_arr = 0:2:360; % 1 x 181
doa_arr = 0:2:360; % 1 x 181

cost_func = zeros(length(doa_arr));

J = fcreateJ(Nc); % 31 x 31 matrix such that 1st entire row is zero,then in 2nd row,1st element is 1 and remaining are all 0's, then this is shifted in 3rd row by 1 position towards right, then same is done for 3rd row and so on

index1 = 1;
for doa = doa_arr
    index2 = 1;
    for dod = dod_arr
        for k =1:3
            A_temp = (Code_mat_des'*J^delays(1,k)*Code_mat_des)/Nc;
            A = kron(A_temp,eye(N));
            
            S = spv(array_RX,[doa 0]);
            S_bar = spv(array_TX,[dod 0]);
            S_man = kron(conj(S_bar),S);
            cost_func(index1,index2) = cost_func(index1,index2)+(S_man'*A'*A*S_man)./(S_man'*A'*P_En*A*S_man);   
        end
        index2 = index2+1;
    end
    index1 = index1 + 1;
    doa; % semi colon put by Me
end
end

[Walter Roberson]

Because Array_TX is not defined by that code.

[Sadiq Akbar]

Yes you are rigth dear Walter Roberson. Thank you so much.