NHZ-TH sequences for quasi-synchronous UWB systems
In this paper, we propose a novel set of time-hopping (TH) sequences with no-hit zone (NHZ) suitable for quasi-synchronous time-hopping spread spectrum ultra wideband (QS-THSS-UWB) systems. Different from the existing NHZ-TH sequences, the constructed NHZ-TH sequences not only have good TH auto-correlation and cross-correlation properties in the range of NHZ, but also have large ratio of the number of sequence elements to the number of time slots. As a result, the QS-THSS-UWB systems employing such NHZ-TH sequences can be without multiple-access interference (MAI) as long as the shifts between sequences don't exceed the NHZ, while the ability of anti-detection and anti-interception of systems will be improved greatly. We provide the construction algorithm of such NHZ-TH sequences and analyze its TH correlation properties. Also, the performance comparison between the proposed NHZ-TH sequences in this paper and the existing NHZ-TH sequences is presented