| Frequency hopping communication is one of the most popular ways of spread spectrum communication, which is a kind of communication method based on the fixed frequency hopping sequence to change the carrier frequency. The frequency hopping system has the advantages of high frequency, high capacity, stable and reliable channel, wide area bandwidth, communication is not limited by geographical conditions, supporting a variety of data services and other advantages, and these make it become a common communication channel. At the same time its high performance and high reliable information transmission capability make hopping system become the strategic target of the military power to achieve global strategy. With the popularization of wireless communication, the communication of information on the battlefield is also developed, especially the electronic countermeasure and electronic interference. So the electromagnetic environment becomes more complex. Radio Cognitive(CR) technology is known as smart radio, which is a technology that can automatically identify the electromagnetic environment and adjust its parameters to achieve more convenient and convenient communication services. The combination of cognitive radio and frequency hopping technology can effectively improve the anti-jamming and security of the frequency hopping system, and make full use of the spectrum resource. In this paper, the adaptive frequency hopping system based on cognitive radio is realized on the basis of theory, and a complete set of frequency hopping communication platform is completed. The main work of this paper includes the following aspects:Firstly, this paper analyzes the current situation of the development of frequency hopping, studies the historical background of the development of frequency hopping and the bottleneck of the development of the current situation. It is concluded that the traditional frequency hopping technology can’t meet the needs of the current social and military development, and the combination of cognitive radio and frequency hopping technology can effectively promote the development of wireless communication, and on the basis of the present theory, the hardware platform of adaptive frequency hopping is proposed.Secondly, With the upper computer PC members, a set of protocol adapted to the upper communication of the current system based on LLC frame is designed to ensure the system to operate accurately and effectively, also we develop the FPGA program about the network port communication, and the three speed adaptive rate channel configuration of PHY chip and MAC core is realized.Then a set of data preparation processing section is designed at the bottom, which supports dynamic parameter configuration. This part of the design is for the current system has multiple communication mode decision factor combination of many communication mode, and dynamic parameter configuration for convenience of debugging and changing system parameters is added, it is also a set of standard unified interface data preparation module. The data received from the network is provided in the standard format to the back-end modulation module, including the operation of the mode transformation, the command parsing, and so on.Finally, after rigorous calculation and simulation, the design of the control mechanism of the non-real time data transmission between the upper computer PC and the underlying FPGA is accomplished. The design of the flow control mechanism ensures that the upper computer can send a large amount of data in a relatively rapid rate, and the bottom layer can receive all the data accurately,and realize the seamless conversion of data in the format of the format of the net frame to the format of the data stream at the bottom, and convert non-real time, discontinuity and random data into stable and seamless data stream processing. It is a high performance accurate flow control mechanism. |
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