DUAL-MODE TYPE ALGORITHMS FOR BLIND EQUALIZATION

Adaptive channel equalization accomplished without resorting to a trai ning sequence is known as blind equalization. The Godard Algorithm and the Generalized Sate Algorithm are two widely referenced algorithms f or blind equalization of a QAM system. These algorithms exhibit very s low convergence rates when compared to algorithms employed in conventi onal data-aided equalization schemes. In order to speed up the converg ence process, these algorithms mag be switched over to a decision-dire cted equalization scheme once the error level is reasonably low. In th is paper, we present a scheme which is capable of operating in two mod es: blind equalization mode and a mode similar to the decision-directe d equalization mode. In this proposed scheme, the dominant mode of ope ration changes from the blind equalization mode at higher error levels to the mode similar to the decision-directed equalization mode at low er error levels. Manual switch-over to the decision-directed mode from the blind equalization mode, or vice-versa, is not necessary since tr ansitions between the two modes take place smoothly and automatically.