Tuning UWB signals by pulse shaping: Towards context-aware wireless networks

Abstract

Tuning spectra by pulse shaping is feasible in both impulse radio (IR) and continuous radio transmissions, since, as well known, the impulse response of the pulse shaper affects the spectral properties of radiated signals. What is peculiar to IR-UWB, and makes pulse shaping particularly appealing, is the impulsive nature of the carrier. Given their very short duration, transmitted pulses in different intervals overlap neither on clock beats nor in between two clock beats. Spectrum matching in IR can thus be restricted with reasonable approximation to a single inter-pulse interval, and as such be redirected in a rather straightforward way into a waveform representation problem. This paper analyzes the above problem of tuning radiated IR-UWB signals to reference spectral patterns by pulse shaping, and shows the correspondence between spectrum and waveform matching problems. Examples of application include three case studies: matching the FCC emission masks, mitigating interference in the ISM bands, and reducing inter-system interference for two coexisting UWB networks. The proposed approach goes beyond the signal processing analysis to tentatively propose a procedure and related protocol for integrating spectral adaptation mechanisms into network operating principles.