Integer-Valued GARCH Process
Résumé
An integer-valued analogue of the classical GARCH$(p,q)$ model with Poisson deviates is proposed and a condition for the existence of such a process is given. For the case $p=1$, $q=1$, it is explicitly shown that an integer-valued GARCH process is a standard ARMA$(1, 1)$ process. The problem of maximum likelihood estimation of parameters is treated. An application of the model to a real time series with a numerical example is given.