Method and receiver for obtaining channel estimated values for equalising digital signals

摘要

In the case of correction methods for digital transmission, a high efficiency can be achieved only when the correction parameters are adapted relatively accurately to the channel. To determine the parameters, a channel estimation is frequently firstly carried out with the aid of a training sequence. The quality of this channel estimation influences the efficiency of the overall system decisively. The object of the invention is to make available a method and a receiver (50) with the aid of which the quality of channel estimated values obtained using correlative or maximum likelihood methods can be improved in a simple way. The efficiency of the optimum MMSE estimating method is thereby to be approached, there being no need for advance knowledge of the channel in the form of coefficient variances, and no intention of averaging over a plurality of receiving blocks, which is frequently impossible in practice. This object is achieved according to the invention by determining weighting factors for the original channel estimated values which are produced by mapping the estimated values from a "soft" characteristic whose variation is influenced, for example, by the noise variance estimated in the receiver.