Strength of Augmented Responses in Linear Overloaded MIMO Detection

In this paper, the appropriate strength of augmented responses is investigated in linear multi-input multioutput (MIMO) detection. The augmented responses is used to generate a square channel matrix for applying linear MIMO detection schemes in overloaded MIMO systems. It is originally proven that the strength of augmented responses should be as small as possible. If gradient descent direction random walk MIMO detection is applied, the augmented responses limits the step size of the gradient descent algorithm. Thus, the strength of the augmented responses effect on the convergence rate of the gradient descent algorithm and bit error performance. Numerical results obtained through computer simulation show that the optimum values of the augmented responses exists.