A Novel Scheme Of Efficient Frequency Hopping Systems Based On Cognitive Radio

The FH system is widely used in anti-interference communication in various channel environments due to its reliable performance.In order to improve the efficiency of FH systems,MDFH technology has been proposed in recent years.MDFH technology uses information instead of PN sequence to select the frequency,so the spectrum efficiency is improved.However,the cost is that the receiving end cannot get the frequency-hopping pattern information,so it needs to adopt blind detection.So the system performance is affected by interference.In order to improve the poor anti-interference performance of MDFH,this paper combines cognitive radio technology and proposes a cognitive message-driven frequency hopping communication system(C-MDFH).Based on the traditional energy detection and sensing technology,the receiving mode of message driven frequency hopping is improved to improve the reliability of the system.At the same time,two frequency band partitioning algorithms are proposed to solve the problem of dynamic mapping of driver bit.Finally,it is proved by theoretical derivation and simulation that the C-MDFH system has better antijamming performance under partial frequency band interference and mono-tone interference.The main content of this paper is divided into three parts.First of all,based on the shortcomings of conventional FH systems,this paper combines the advantages of MDFH and C-FH,and proposes a novel system architecture.In the new scheme,the frequency-hopping pattern controlled by the driver bit is randomized,which improves the comprehensive performance of the pattern.In addition,this paper mainly designs two kinds of frequency band division schemes,namely frequency point transfer plan and frequency point mapping plan,and compares the performances of these two plans respectively.In addition,this paper improves the traditional energy detection and perception algorithm of CMDFH system,and designs a double-threshold detection and perception algorithm.Secondly,based on the two frequency band division schemes proposed above,this paper analyzes the spectral efficiency of the two schemes under the Gaussian white noise channel,and through comparative analysis,it is concluded that the C-MDFH system have higher transmission efficiency than FH and C-FH systems.After the analysis of the BER performance of C-MDFH system,C-MDFH system was deduced in the partial band interference,and the error rate under the single tone jamming,and through the simulation analysis in part C-MDFH system interference and single tone jamming,and multipath fading channel anti-interference performance of channel environment,and through the comparison and analysis it is concluded that the C-MDFH system under the interference of ber performance and theoretical derivation are basically identical.After that,compared with conventional MDFH system,C-MDFH system has a great improvement in error performance under partial frequency band interference and monophone interference.In addition,the analysis of C-MDFH system in Rayleigh fading channel shows that the BER of C-MDFH is improved compared with that of conventional cognitive frequency hopping by theoretical analysis and simulation verification with the same efficiency.Finally,this article designs the FPGA hardware implementation of the cognitive frequency hopping system on the basis of the previous parts,and introduces the transmitter and receiver modules in detail.The transmitter is divided into baseband data module,baseband modulation module,analysis module perception,frequency-hopping modulation module,receiver,including synchronization module,the solution of jump module,baseband demodulation module.In this paper,the function realization,interface design,simulation results and upper board debugging results of each module are introduced.First of all,the behavior-level simulation show that the baseband waveform generated by the C-FH system established by Verilog language is correct,and the functions of modulation,synchronization and demodulation can be completed normally.Finally,two FPGA development boards are used to conduct wireless joint tuning,and the correctness of the joint tuning results proved the feasibility of the design scheme.