CMI and IFI mitigation for TH-PPM Ultra Wideband systems with a low complexity receiver

Pulse position modulation (PPM) is a popularly adopted modulation scheme in the impulse radio based ultra wideband (UWB) systems. In order to shape the spectrum of the signal, a time dither on generated pulses leading to so-called Time Hopping UWB (TH-UWB) is introduced. Although of many advantages, the TH-PPM scheme faces serious challenges which are the cross modulation interference (CMI) and the inter frame interference (IFI) due to the multipath propagation. In this paper, Time Reversal is proposed as a technique for mitigating the CMI and IFI in TH-PPM UWB systems at the transmitter side. The CMI and IFI amount can be assessed by Signal-to-Interference-Ratio (SIR). Simulation results show that the proposed approach can improves the BER performance of the system considerably. We focus here on the single-user case, however, we can extend the result to the multi-user case by using different TH codes.