Research On Narrowband Interference Suppression Based On The Deep Wavelet Packet Transform In The IR-UWB System

Ultra Wideband (UWB) is considered the most promising communication technologies.Impulse Radio Ultra Wideband (IR-UWB) is a high-speed, low-power, short-range wirelesscommunication systems. In the IR-UWB system, the pulse duration is nanosecond level, sothat the bandwidth of IR-UWB system can achieve GHz level. The transmission power islimited to-43.1dBm/MHz in the band of3.1GHz to10.6GHz. In the IR-UWB system, thepower spectral density (PSD) is relatively low. So the IR-UWB system does not interferewith the existing narrowband system. But the IR-UWB system is easily disturbed in thewireless communication systems that its frequency bands coincide with the band of IR-UWBsystem. The result of interference in the IR-UWB system is not ignored.This paper presents the method of based on the deep wavelet packet transformmulti-threshold to remove the interfering signals, and this method is applied in the IR-UWBsystem to mitigate the narrowband interference (NBI). Through analysis and research, thismethod can be applied in the IR-UWB system removing the unwanted signals and caneffectively suppress the NBI.The main work of the paper:(1) Firstly, this paper presents the method of based on the deep wavelet packettransform multi-threshold to remove the interfering signals. The main idea of this method isthat the original signal is decomposed by wavelet packet. The paper presents that the waveletpacket coefficients are encoded using binary gray code. Rearrangement the waveletpacket coefficients through the order of binary gray code can get in accordance with theorder from low to high frequency. Make a standard to divide the all bands into the lowfrequency bands, the intermediate frequency bands and the high frequency bands. Accordingto the different bands of the interference signals select the different thresholds criterion for removing the corresponding wavelet packet coefficients. Finally, by reconstructingthe original signal by the undeleted wavelet packet coefficients can remove theinterference signal.(2) Simulate to the waveforms that the pulse signal in the IR-UWB system adding theinterference signals by using the based on the deep wavelet packet multi-threshold method toremove the interfering signals, and the multi-threshold method is compared with the otherfour methods of single threshold criterion by the waveforms, BER and SNR. It can know thedeep wavelet packet-based multi-threshold method can remove the interference signals. Themethod that the paper proposed removing the interfering signals is better performance thanthe other four methods.(3) Make the GSM900, GSM1800and IEEE802.11a as the NBI., the second derivativeGaussian pulse as the IR-UWB pulse, using TH-PPM modulation, S-V multipath channelmodel (IEEE.802.15.3a) and P-Rake receiver. Remove the NBI signal in the IR-UWBsystem by using the method of the based on deep wavelet packet multi-threshold. Throughthe different situations BER performance simulation shows that based deep wavelet packetmulti-threshold method can effectively alleviate the NBI.