Key Technology Research And Verification Of Link16 Data Link Transmission Waveform

Link16 is a new data link developed by the United States based on the requirements of joint operations on the basis of Link4 and Link11.It has the advantages of strong confidentiality and strong anti-interference ability.Based on the existing literature on the Link16,this paper studies and verifies the key technologies of its transmission waveform.The main work covered in this paper is as follows:Firstly,we summarize the principle of the Link16 data link.The JTIDS principle is introduced from four aspects:time division,communication mode,access mode and time slot.We mainly introduce the fixed J series message.Then we sorte out the message packing process and establish the transmission waveform model on the Matlab platform.Finally we introduce the function of each module briefly.Then,we finished key technologies research in the physical layer.,including GMSK modulation and demodulation,power automatic gain control,CCSK spread spectrum.And then we compare one-bit differential demodulation(B_b T_b=0.5)performance and two-bit differential demodulation(B_b T_b=0.5)performance,the two-bit differential demodulation performance is better than the one-bit differential demodulation performance of about 1.3dB,comparing the effect of different B_b T_b values(B_b T_b=0.5,B_b T_b=0.32)on one-bit differential demodulation performance.We compare the signal phase based AGC algorithm and the log semaphore based AGC algorithm.The first algorithm is easy to implement,what’s more,it has no gain jitter.Thirdly,the implementation of the Link16 transmission waveform is completed on the FPGA platform.Firstly,the architecture of the hardware platform and the clock relationship are introduced.The implementation details of the key modules are introduced in detail.The guard interval mechanism is used in the time synchronization unit to prevent the correlation peak leakage detection to improve the synchronization performance.After the final processing,the signal is sent in the form of double pulse.In the end,we complete the transmission waveform debugging and verification.The time synchronization function test and the point-to-point bit error rate test are completed in the wireless point and coaxial line connection situation.The test results show that the system can carry out communication function,which verifies the feasibility of the scheme.The physical layer waveform of Link16 data link realized in this thesis has certain practical significance,which provides reference for the imitation of foreign military data link.