Performance Analysis Of Several Anti-interference Preamble Signal Detection Methods

Underwater wireless communications technology has been widely used in marine scientific research,underwater resource detection and ocean navigation,which has made it a research hotspot in recent years.As the starting step of underwater acoustic communication,the preamble detection plays an important role.Any misdetection and missed detection will cause the communication quality to drop,and even lead to the failure of this communication.Because the underwater communication environment has the characteristics of rich multipath,serious Doppler effect and various interference signals,it often leads to the performance degradation of traditional preamble detection methods and difficulty in selecting thresholds.Therefore,this paper makes an in-depth analysis of the performance of several common anti-interference preamble detection methods,and provides guidance for its application in underwater acoustic communications.For the normalized matched filter(NMF),a closed expression for the detector's detection performance is given.NMF is a commonly used method for detecting leading signals.It has the ability of simple structure and resistance to interference signals.Based on the basic binary hypothesis test model,this study obtains the test statistic of NMF according to the generalized likelihood ratio criterion,and then obtains the distribution of the test statistic under Gaussian white noise.Through this distribution,the relationship between the detection probability and the false alarm probability is given,and the final detection performance is obtained.The correctness of the above performance analysis of the detector was verified by simulation and experimental data analysis.Inspired by the NMF method,this paper further analyzes narrowband interference,partial-band partial-block-duration interference,and detectors with rich multipath environments.Narrowband interference is an interfering signal that lasts for the total duration of the signal,usually from mammals in the ocean and other narrow-band sonar systems;the duration of the partial-band partial-block-duration interference is only a fraction of the total duration.Due to the reflection of the water surface and the sea floor,there are abundant multipath in underwater communication,which will reduce the performance of the preamble detection.Therefore,under the narrow-band interference and partial-band partial-block-duration interference environment,the basic binary hypothesis test model based on the multipath HFM(Hyperbolic Frequency Modulation)preamble is given,and based on the generalized likelihood ratio criterion,the optimal detector under two kinds of interference is obtained.Furthermore,the performance of the optimal detector under the above two kinds of interference is analyzed,and the relationship between the detection probability and the false alarm probability is obtained,which is used to guide the application of the preamble detection in underwater acoustic communication.In the subsequent Monte Carlo simulation experiments and experimental data analysis,the proposed method is obviously superior to NMF,matched filter and Page Test(PT)detection method.