Design Of Non-cooperative Cognitive Communication System Based On Spectrum Sensing

With the rapid development of wireless communication technology and the continuous increase of communication equipment,spectrum resources are becoming increasingly scarce.How to efficiently utilize spectrum resources has become a topic of increasing concern.Cognitive radio technology can use intelligent radio equipment to dynamically,adaptively,and efficiently use spectrum resources.Among these technologies,spectrum sensing technology can detect spectrum holes that can be used by recognized users.This article applies spectrum sensing technology to achieve noncooperative cognitive communication systems by detecting available spectrum.The main research content includes the following aspects:1.This study investigates energy detection-based spectrum sensing algorithms to achieve the communication function of signals.Three different spectrum sensing strategies are employed at the transmitter for channel selection.A fusion-based algorithm is used to judge whether the entire frequency band is suitable for communication by merging multiple results within the frequency band.An optimized cooperative spectrum sensing algorithm is executed multiple times based on the status of the previous moment to determine whether the frequency band is occupied.To deal with malicious interference,modulation switching decisions are made by recording parameters of interfering signals.2.This study investigates non-cooperative cognitive communication algorithms based on signal recognition and demodulation to achieve non-cooperative cognition at the signal receiving end.The system utilizes its own sensing and judgment capabilities to perceive and analyze the surrounding radio environment,including a signal recognition module based on deep learning,a user cognition module,and a channel optimization module.Firstly,spectrum sensing is used to determine whether the signal exists,and convolutional neural networks are employed for signal type recognition.Then,the corresponding demodulation is performed to recover the source data,and frame synchronization is utilized to verify if the signal comes from a communication user.Finally,by calculating the bit error rate,the need for channel optimization is determined,and the sending end is notified,thereby establishing a complete cognitive communication process.3.The entire system design based on software and hardware has been implemented,and the Zynq+Adrv9009 board is utilized for signal transmission and reception.The transmitter’s functions mainly include frequency band switching,frequency point selection,and modulation mode switching;while the receiver’s functions mainly include intelligent signal perception,recognition and demodulation,communication validation,and specific signal acquisition.The board is connected to the upper computer PC software through an Ethernet interface,and received data is sent to the upper computer via the TCP/IP protocol,achieving data interaction between the board and the upper computer software.A display software based on the Galaxy Kylin operating system has been designed for the upper computer part,and users can configure various parameters to meet different needs by calling the upper computer software,which has good human-computer interaction function.After testing,all functions of the cognitive communication system have been successfully implemented.Based on the principle of cognitive radio,this article designs a non-cooperative cognitive communication system based on spectrum sensing,which can adaptively adjust radio communication parameters to different environments and channel conditions,realize signal communication,and has good anti-interference function and concealment.