Positioning of the ILT vs ILR is similar to positioning VLT vs VLR as described in Section 3.2.5.
It is required when the power control in the interfering link is simulated. In case the geometry of your scenario is depend on the position of the ILR (for instance ILR being at the center of the ILT distribution, or the victim link being fixed with respect to the ILR), it is also important to set it.