1. Method for processing a data signal received via a communication channel, comprising determining a first matrix comprising components describing characteristics of the communication channel inverting the first matrix by sub-dividing the first matrix into at least four sub matrices inverting a first sub matrix of the four sub matrices generating a second matrix by multiplying a second sub matrix of the four sub matrices with the inverted first matrix and a third sub matrix of the four sub matrices determining the difference matrix between the second matrix and a fourth sub matrix of the four sub matrices inverting the difference matrix calculating the inverted matrix based on the inverted difference matrix processing the data signal using the inverted first matrix.