Research And Implementation Of Communication Terminal Of Link 16 In Physical Layer Link Based On FPGA

Jointly developed based on the requirements of multiple services for coordinated operations by the United States Navy and forces of North Atlantic Treaty Organization,Link 16 is an updated tactical data link,compatible with Link 4 and Link 11.It has the unique advantages of not only good confidentiality and strong anti-interference ability,but robustness.And the performance of large communication capacity and low delay is equipped.Based on the research of the literature about link 16 at home and abroad,this paper is aimed at not only research on the baseband waveform of Link 16 transmitting in the physical layer link,but implementing it based on FPGA.The work covered in this paper is as follows:First,overview of the characteristics of Link 16 and the principles of JTIDS is given.The message type,format of header words,components of the time slot and data packing structure,in particular,standard format messages of J series are introduced.In addition,characteristics of the JTIDS,TDMA architecture and communication mode is described.Meanwhile,the process of message transmission based on the standard double-pulse format is introduced briefly.Second,It provides the research on the algorithm of baseband link waveform,and simulates it.The algorithm of waveform transmission is modeled and simulated,which is the technology of anti-interference,security in transmission,modulation and filtering.The technology of the RS coding in anti-jamming is focused on.According to model and simulate for it,using the tool of Matlab/Simulink,It is concluded that the signal modulated by MSK transmitting in the channel of AWGN,the bit error rate received is reduced by about three orders of magnitude using the RS coding,compared with the case of not using it.According to the results of simulation,the time-domain waveform of the transmission,It is concluded that double pulses are used to send the same data in a time slot and the time of one pulse is 13 μs.And the mainlobe bandwidth of the spectrum is 7MHz is showed by the spectrum of transmitted signal.In the condition of baseband loopback,the number of error bits received is zero.They all show that the algorithm of waveform transmitting in the baseband link is correct and feasible.Third,the algorithm of waveform transmitting in the baseband link is implemented based on FPGA.The baseband link consists of links for transmitting and receiving.After the transmitting link and the receiving link divided into modules,the design of circuit for all modules is coded with Verilog.After the design is done,it provides the simulation for the key modules.The results show that the key modules designed realized the expected function.Lastly,It is essential to verify the designed system and analyze the results.Report generated by the compiler shows that utilization of RAM/FIFO is up to percent of sixty-four and utilization of BUFG is slightly higher than the standard of percent of fifty.The other logic resource utilization of FPGA is less than the standard.The results of the board-level verification show that the system can work normally.In addition,when the interface of DAC and ADC connected by wire,the signal data captured by Chip Scope and the result displayed by PC both show that the bit error rate is zero all the time as the increase of the number of total bits received.The verification results show that Link 16 system realizes the function of communication,and bit error rate meets the system performance index.And it proves that the algorithm of waveform transmission is feasible.In short,this paper provides reference for the research and implementation of foreign military tactical data link.