Research On Technology Of Coding And Modulation Based On Individual Soldier Broadband Radio

As the main communication tool among soldiers,military broadband radio plays a very important role during the war.In order to satisfy the characteristics of the low delay,strong anti-jamming capability,confidentiality and reliability in the military communication system,some effective measures such as interface resistance and multipath transmission should be taken into the radio system.This paper aims at guaranteeing the communication reliability by investigating the coding and modulation technology of data transmission in the physical layer.The first part introduces the key technology of baseband signal processing in the single soldier broadband radio system and designs the system scheme.The transmitter performs framing by the instruction information and data sent by the control layer program according to the frame format.The header uses spread spectrum technology and BPSK(binary phase shift keying)modulation.The data is scrambled,coded,and modulated by QPSK(quadrature phase shift keying).Then,the transmitter outputs baseband shaping signal after the modulated signal goes into the shaping filter.The receiver obtains the data rate and the number of blocks after synchronization and despreading module.The valid data that taking out from the receiver enter the frequency offset module,frequency domain equalization,turbo decoding and so on.And then,the receiver outputs data information.The second part focuses on the theoretical research and simulation of the turbo code,including various parameters that affect the turbo code analysis and simulation results comparison.Next,turbo code is added to the system for simulation under the AWGN(additive white Gaussian noise)and multipath channel scenario.In the process of system implementation,to deal with the problem of long delay caused by turbo decoding,this paper designs the FPGA implementation structure of the high-speed turbo decoder by adopting MAX-LOG-MAP algorithm.The parallel processing algorithm and the efficient normalization algorithm can greatly reduce the decoding delay and resource consumption.Then,the design is tested on the hardware platform to verify its feasibility by comparing with the theoretical results.Finally,on the basis of realizing the baseband signal processing,the driver is compiled to ensure that the AD9361 chip can work normally to complete the radio frequency part of transmission and reception in the system.The actual transceiver test is proceeded on the ZYNQ-7000 platform to verify the feasibility of the design.To verify the performance of the baseband signal processing algorithm in the actual channel scenario,practical test and data analysis are conducted under the RF signal source,signal analyzer and other equipment.The consistence between the testing and theoretical results shows the reliability of the system.