i am trying to run the below cvx code and when increase the value of K greater than 8, cvx_status turns to infeasible. can anyone please help?

clear all;

clc;

N = 6; % Number of antennas

K = 8; % Number of users

H = randn(N, K) + i*randn(N, K); % random channel matrix
sigma2 = 0.5*ones(K,1); % noise power vector

gamma = 2*ones(K,1); % minimum SINR requirement vector

cvx_begin sdp quiet

variable W(N, K) complex;

expression S(K,1)

for k = 1:K

S(k) = (ctranspose(W(:,k))*H(:, k))/sqrt(gamma(k));

end

expression I(K, K);

for k = 1:K

for m = 1:K

if( k == m)

I(k, k) = sqrt(sigma2(k));

else

I(k, m) = ctranspose(W(:, k))*H(:,m);

end

end

end

expression obj;

for k = 1:K

obj = obj + sum_square_abs(W(:,k));

end

minimize obj;

subject to

subject to

for k = 1:K

imag(S(k)) == 0;

real(S(k)) >= 0;

[real(S(k))*eye(K), I(:, k); (I(:, k))’, real(S(k))] >= 0;

end

cvx_end