Ultra-Wide Band (UWB) is a radio technology that uses a very large bandwidth. A two-dimensional exclusion mechanism and routing strategy are mentioned in . We extend the exclusion region to three-dimension and modify the interference from other nodes as Gaussian Noise. The conclusion is also correct under mobility. We also present a new model combining exclusion mechanism and interference mitigation. Then we propose an optimal routing algorithm described as MTI. We raise a geometrical method unlike the simulation in  to demonstrate that the MER routing minimize the total interference and is the optimal routing.