The research of modulation recognition algorithm base on softwore radio

In order to solve the question of low recognition rate and complex identification process in software radio automatic recognition of modulation standard issue, the technology of Decision Tree was put forward. After studying the characteristics of digital signals and the characteristics of feature parameters, then we need to select the appropriate tree structure, determine the characteristic parameters which used on each non-end node, and choose a suitable decision threshold. It has a great influence on the recognition results through analysing the comparison of parameters with the different order, then we get the best decision tree. Use of decision tree 2ASK, 4ASK, 2PSK, 4PSK, 8PSK, 2FSK, 4FSK selected for identification, obtained the recognition rate more than 85% under conditions of SNR 10.