UWB Pulse Design Based N The Systems Coexistence

UWB is comprehensively focused on due to its various advantages, especially; the issue of coexistence between the UWB and traditional narrow band communication systems is the researching hot spot in recent years. The Subject of this paper is from one of sub-topics of the National Nature Science Fund project, which has significant theoretical and practical values.In this paper, based on the analysis of UWB interference and interference avoidance, and some other key technology, two UWB pulse design methods are presented based on Chirp signal and radial basis function (RBF) neural network, respectively.For the UWB pulse design method based on Chirp signal, the whole UWB frequency band is divided into several sub-bands, and for different sub-band, linear Chirp waveforms are adopted with different center frequency and different weights, respectively. Then combine all of the Chirp waveforms, based on Mean Square Error algorithm, try to match the radiation emission mask, and generate the UWB pulse.For the UWB pulse design method based on radial basis function (RBF) neural network, Firstly, the UWB pulse design problem is abstracted as a classic interpolation in mathematics, then Gaussian function is chosen as the basis function, utilizing the RBF neural network to implement the interpolation. Besides, cognitive radio is introduced to detect the spectrum using state to generate the target emission mask, learned by the RBF neural network, when the network converge into the optimal value, do IFFT to the network output, and we can get the designed UWB pulse.From the simulation results, it can be seen that the designed UWB pulses in our paper behave much better than the directly modulating Chirp signal and other traditional UWB pulses in the context of spectrum utilization ratio and transmission performance.