In IDMA Systems multi-user detection requires solving a MAP problem with gets computationally prohibitive when the number of users and/or the lengths of the channel impulse responses increase above a certain point. A reduced complexity sub-optimal approach is the so called soft-RAKE detection which assumes statistical independency among multipath propagations. However, as the number of multipaths increase, the SINR per path decreases. Below a certain threshold the initial SINR per layer is too low to start convergence and the iterative detection fails. The goal of this thesis is to design and implement procoding filters which shorten the effective impulse responses and concentrate the energy of the channel in a few channel taps. Starting with perfect channel knowledge at the transmitter, also the influence of imperfect channel knowledge shall be investigated. As an optional additional step, also channel estimation at the receiver can be considered, leading to a more practically relevant investigation.