Abstract: In response to the difficulty in determining the characteristics of users and data for mobile terminal access, which leads to high difficulty in access control, an access control technology based on EVM(Error Vector Magnitud) measurement algorithm is proposed to effectively solve the problem. Considering the impact of noise and other interference factors in the environment, the Qos(Quality of Srvice) condition is used as the initial access condition for users. The characteristics of users or data that meet this condition are calculated, and the feature values are converted into weight factors as reference for access control. The EVM measurement algorithm is used to calculate the difference between the internal and external signals of the terminal channel, and the user weight factor is used to derive the access threshold of the mobile terminal. The increasing and decreasing functions between different user threshold values and control values are solved, and precise control of mobile terminal access is achieved according to the priority order of the functions. The experimental data shows that the proposed method has high access control accuracy, and after control, the terminal transmission delay and blocking rate have been significantly improved, and the data arrival rate has also been significantly improved. 

Key words: error vector magnitud (EVM) measurement algorithm, mobile terminal, access control technology, quality of service(Qos) conditions, decreasing function