Blind equalization with gradually increasing filter length (GRINFIL)

A major drawback of the existing adaptive blind equalization algorithms is their slow rate of convergence. We have developed a new adaptation technique which overcomes this handicap with no significant increase in computation. Our method starts the adaptation process with a short equalizing filter length, switching to a longer equalizing filter length when the shorter one cannot decrease the intersymbol interference (ISI) anymore, and continues this process until a low ISI level is reached. One significant advantage of this method is that during the adaptation process, we can use any one of the Bussgang type equalization criteria, henceforth speeding up each and every Bussgang algorithm. Simulation results show very fast convergence rates, compared to the original algorithms applied with fixed filter lengths.