Link Coding And Waveform Implementation In Multi Protocol Terminal

In essence,data Link is a data network composed of all kinds of transmission information.Under the ability of data Link information sharing,data terminals connected to this network can share and complement information with other terminals on the same network.However,due to the differences in communication technology and specific application fields,there is no efficient data Link that can replace other data Links to fully meet the needs of all applications.The multi protocol terminal can connect two or more data Links,realize the information sharing and information conversion of data Link messages while multiple data Links do not interfere with each other's independent operation.This paper studies and designs a LDPC-OFDM data Link which is suitable for multi protocol terminals.The data Link uses LDPC coding for the transmission data,OFDM as the channel transmission mode,and interacts with the terminal controller through the network port.The main contents of this paper include:The implementation of LDPC Encoding and decoding process on DSP is realized,and the accuracy of data transmission and high transmission rate are ensured.The performance of LDPC code is optimized,the floating-point data before LDPC code decoding is fixed-point processed,and the fixed-point number is used for LDPC decoding numerical operation.According to the actual engineering needs of the multi protocol terminal,the physical frame structure of OFDM is designed,and the main function code is compiled according to the frame structure.The information transmission between the sending time slot and the receiving time slot is divided reasonably by four subfunctions to optimize the logic structure of the OFDM code.In order to fit the multi-core and multi-threaded characteristics of sb3500 chip,the multi-core and multi-threaded design of DSP code is done.The implementation of LDPC-OFDM Link in multi protocol terminal is completed.Add the synchronization head of Link 16 in front of the frame structure of OFDM.In the receiving process,the first synchronization of Link16 is carried out,and the second demodulation of OFDM or Linkl6 is carried out respectively.Update Link control primitives in multi protocol terminals.Based on the Link 16 primitive system,some new primitives are added to represent the Link program module of LDPC-OFDM and the message and control relationship between devices.