ARMA(2,2) maximum likelihood estimation

How to estimate ARMA (2,2) like this one :

y = delta + phi*(1.5*y(t-1) - 0.5*y(t-2)) + ut - teta*(1.5*u(t-1) - 0.5*u(t-2))

i tried this :

Mdx = arima('AR',{1.5,-0.5},'MA',{-1.5,0.5});
EstMdx = estimate(Mdx,y);

y is my variable, first thing i have error. Second thing i don't know how to precise that matlab must estimate 1 phi and 1 teta because matlab estimates as parameters numbers if we have ARMA(2,2) he will estimate phi 1, phi 2, teta1, teta 2 .

Thanks

[Bijal Patel]

Me too, I have the same question.

Did you find a solution ?