Based on the principle of OFDM system, the paper mainly includes the following aspects: the development of mobile communications, the characteristics of the radio channel, OFDM system theory, the advantages and disadvantages, key technologies, and adaptive technology of the OFDM technologies.Next, the OFDM symbol function, time domain and frequency domain model is analyzed detailed by some basic knowledge, some basic knowledge of Convex optimization problem.-Based on the principle of OFDM system, the paper mainly includes the following aspects: the development of mobile communications, the characteristics of the radio channel, OFDM system theory, the advantages and disadvantages, key technologies, and adaptive technology of the OFDM　technologies.Next, the OFDM symbol function, time domain and frequency domain model is analyzed detailed by some basic knowledge, some basic knowledge of Convex optimization problem.