In ultra-wideband (UWB) ad-hoc networks, the performance degrades due to the severe near-far problem. In this paper, we aim to reduce the effect of large near-far ratio interfering users in UWB ad-hoc networks. We proposed a low-complexity decision-feedback interference suppression scheme where the decoder output is used to estimate the reliability of the channel. Then, the received samples are combined according to the estimated reliability level. The proposed technique can be used without knowledge of spreading sequence, received timing and power of the other users. It is shown that by using the proposed scheme, the error rate performance improves drastically compared to the conventional MF receiver when the near-far ratio is relatively large. Furthermore, we examine the effect of coding and spreading parameters on the performance of the proposed technique. As a result, the number of required retransmission is reduced, and thus, high power efficient transmission can be achieved.