Narrowband interference suppression in time-hopping impulse radio ultra-wideband communications

TLDR: In the presence of NBI, the TH-IR system and MC-CDMA system achieve similar performance when both use a notch filter, and a performance comparison between TH-ir and multicarrier code-division multiple-access UWB systems is made.

Abstract: Ultra-wideband (UWB) technology has been considered an innovative solution for future short-range high-speed wireless communications. Interference suppression is important for the UWB devices to operate over spectrum occupied by narrowband systems. In this paper, the use of a notch filter in time-hopping impulse radio (TH-IR) for UWB communication is considered, where a Gaussian monopulse is employed with pulse position modulation. Lognormal channel fading is assumed, and a complete analytical framework is provided for the performance evaluation of using a transversal-type notch filter to reject narrowband interference (NBI). A closed-form expression of bit-error probability is derived, and the numerical results show that the use of a notch filter can improve the system performance significantly. Furthermore, a performance comparison between TH-IR and multicarrier code-division multiple-access (MC-CDMA) UWB systems is made under the conditions of the same transmit power, the same data rate, and the same bandwidth. It is shown that in the presence of NBI, the TH-IR system and MC-CDMA system achieve similar performance when both use a notch filter

Figures

Fig. 7. Error probability as a function of interference power to signal power ratio.

Fig. 1. Sample of UWB TH-IR waveform (N = 3 frames, N = 4 bins).

Fig. 11. System performance as the center frequency of the NBI varies.

Fig. 8 BER for different Rake complexities.

Fig. 10. Error probability versus the bandwidth ratio.

Fig. 9. System performance corresponding to different numbers of taps per side of the notch filter.