Dynamic Screening Transform Domain Communication System Based On Spectrum Sensing

With the innovation and progress of wireless communication technology,the electromagnetic environment is becoming more and more complex,and the electromagnetic equipment that interferes with the normal wireless communication is increasing day by day.Transform Domain Communication System(TDCS),as an anti-jamming communication system that senses spectrum resources and uses the sensing results to complete transmission and receive,can utilize spectrum resources more flexibly.In this thesis,a dynamic screening transform domain communication system based on spectrum sensing is designed.Compared with the conventional transform domain communication system,this system will focus on how to dynamically screen the transform domain communication frequency band,and how to break through the fact that the transform domain communication transceiver must be in the same electromagnetic environment.In view of the shortcomings of the current conventional transform domain communication system that needs to select a fixed communication frequency band in advance,the frequency spectrum resources cannot be dynamically utilized and the range of the optional frequency band is insufficient.The spectrum sensing module proposed in this thesis can segment a wider frequency band,so that each subband can complete spectrum sensing separately,and dynamically select the subband with the lowest spectrum occupancy rate from it,and use it as the communication frequency band of the transform domain communication system.This sensing method can not only increase the optional communication frequency band,but also can dynamically use the spectrum resources to complete the transform domain communication.In addition,in view of the limitation that the transceivers of the conventional transform domain communication system must be in the same electromagnetic environment,the transform domain communication system proposed in this thesis introduces a direct spread spectrum communication interactive link,so that the transmitter can share the electromagnetic environment information perceived by the receiver;After the receiver completes spectrum sensing,it screens out the optimal subband,generates its amplitude spectrum,and transmits it to the transform domain transmitter through the direct spread spectrum interactive link.The transmitter uses the received receiver spectrum information to complete transform domain communication processing and transmiting.This interactive link enables the communication transceivers to share and use the same spectrum information to complete the transform domain communication even if they are in different electromagnetic environments,thereby improving the anti-interference performance of the transform domain communication system.The specific scheme of the dynamic screening transform domain communication system proposed in this thesis according to the above research directions is divided into three stages:first,the host computer sends the spectrum sensing start command to the receiver,and the receiver completes spectrum sensing for multiple subbands and performs amplitude spectrum shape,and screens out the optimal subband with the least interference,uploads the sensing results to the host computer,and at the same time uses the optimal subband information to complete the high-gain anti-jamming transmission through the direct spread spectrum interactive link;the transmitter uses the direct spread spectrum interactive link The channel receives the optimal subband information,processes the shared subband information and the communication source code in the transform domain and completes the transmission;after the receiver completes the interactive link transmission,it receives the transform domain communication signal according to the subband center frequency,and performs transform domain receive,processes restore communication data.According to the above content,this thesis first introduces the development and current situation of transform domain communication,analyzes and introduces various theories used in the system,and introduces the overall scheme in detail and conducts simulation comparison analysis with the conventional transform domain communication method.The hardware test platform designed by the transceiver is introduced,and finally the implementation test of the whole system is carried out,and the implementation test diagram of each part is displayed and analyzed.According to the final test results,the new transform domain communication system proposed in this thesis has completed the design requirements.