```
Nr_set=2;
K_set=6;
T0=1e-3;
sigma = 1e-11;
sigma_h = 1e-11;
P_tx=2;
%%
Nt = Nt_set;
Nr = Nr_set;
K = K_set;
Variable=num2cell([Nt,Nr,K,T0,sigma,0,P_tx]);
[H_nomi]=system_channel(Variable);
%%
b = ones(Nt,K);
cvx_begin sdp
variable lambda(1,K) nonnegative
variable t(1,K) nonnegative
variable a(Nr,1) complex
expression phi(Nr*Nt,K);
expression vk(1,K);
minimize sum(t)+sigma*pow_pos(norm(a'),2)
subject to
for k=1:K
phi(:,k) = vec(a*b(:,k)');
vk(k) = a'*H_nomi(:,:,k)*b(:,k)-1;
[lambda(k)*eye(Nt*Nr)-phi(:,k)*phi(:,k)',-1*phi(:,k)*vk(k)';-1*vk(k)*phi(:,k)',t(k)-pow_pos(norm(vk(k)),2)-lambda(k)*sigma_h]==semidefinite(Nt*Nr+1);
end
cvx_end
```

%%%%%%%%%%%%%%%%

The problem is shown as follow

Error using * (line 126)

Disciplined convex programming error:

Only scalar quadratic forms can be specified in CVX

There is something wrong in

[lambda(k)*eye(Nt*Nr)-phi(:,k)*phi(:,k)’,-1*phi(:,k)*vk(k)’;-1*vk(k)*phi(:,k)’,t(k)-pow_pos(norm(vk(k)),2)-lambda(k)*sigma_h]==semidefinite(Nt*Nr+1);

but I don’t know the reason. How can I solve it? Thinks!!