Time-Hopping Patterns derived from Permutation Sequences for Ultra-Wide-Band Impulse-Radio Applications

Time-hopping (TH) communication techniques have gathered increasing attention since the introduction of ultra-wide-band impulse-radio, by Scholtz, in 1993. In these systems, the design of TH sequences is a critical point, since they constitute the only source of diversity that protects the transmitted signal from the interference caused by multipath and by the presence of other users. Moreover, they represent a reliable source for synchronization and channel estimation. In this paper the author addresses the issue of building TH patterns with very good correlation properties by use of a construction based upon the theory of permutation-sequences (PSs) that was recently proposed in the context of frequency-hopping by Moreno. The paper devotes much care in the analytical evaluation of correlation properties (correcting some mistakes of the literature) and in the identification of the widest possible class of TH patterns based upon PSs. Key-Words: Impulse radio, ultra wide band, time hopping, frequency hopping, permutation sequences.