Research On The Ultra-wideband Pulse Designing And Ultra-wideband Channel Model For 15m To 25m

Recently ultra-wideband (UWB) wireless technology has become the mostpopular physical layer technology for a short distance, high-speed wireless networkapplication. FCC (Federal Communication Commission) proposed the emission maskfor the UWB pulse. During designing the UWB pulse the emission mask and thespectrum distribution must be taken into consideration. Many effective methods havebeen presented, such as carrier modulation shaping technology, Hermite pulseshaping technology and Gaussian pulse shaping technology. These technologies arebetter use of emission mask in the band of 3.1Ghz to 10.6GHz, but not in the band of3.1GHz below.For the UWB channel model, the famous models are△-K model ,Salen-Valenzula model and the IEEE802.15.3a standard multi-channel model. Butmost of these models are based on the given experimental data analysis of the channelparameters with the transmission distance of 10 meters below, the parameters andcharacteristics of more remote channel is not given.The paper's focus is as follows:A pulse designing method based on the wavelet theory and genetic algorithm isproposed. It makes use of several wavelet functions to mix the UWB pulse, whichmore fully utilizes emission mask particularly in the low frequency spectrum tosatisfy the emission mask. Meanwhile, the genetic algorithm is applied into thedesign process, and the results can achieve optimal solution convergence. The designideas are universal, and can be used to pulse design with the spectrum requirements.Meanwhile, the comparative analysis is given among the pulse designing methodbased on the wavelet theory and genetic algorithm, UWB pulse orthogonal designingalgorithm, Hermite pulse shaping technology and Gaussian pulse shaping technology.Gaussian functions and its higher-order derivative and Hermite pulse by changing itsparameters can meet the FCC emission mask, but only from 3.1GHz to 10.6GHz.UWB Orthogonal pulses are orthogonal, but without enough spectrum utilization. This method proposed in the paper could more fully utilize emission mask, not onlyfrom 3.1GHz to 10.6GHz, but also in the band of 3.1GHz and below. With thevicinity of a larger decline near 2GHz, it can effectively reduce interference withUMTS/WCDMA communications systems.Finally, the ultra-wideband signal transmission characteristics are analyzed inthree propagation environments: LOS (Light of Sight), OLOS (Obstacle Light ofSight), and NLOS (Non-light of Sight) with the distance from 15 meters to 25 meters.The experimental data are based on the UWB measurement database of Swiss FederalInstitute of Technology. Before only the channel propagation characteristics of 10meters below were analyzed. However, the 15 meters to 25 meters of signalpropagation characteristics are presented in the paper. In the experimental dataprocess, the original data are under zero-interpolation operation and spectrumsymmetric operation to improve results accuracy. Meanwhile the CLEAN algorithmis adopted in the data processing, which was only used in astronomy signalprocessing. Lastly we apply the pulse designed in the paper to the channel model.