Adaptive Modulation Metod for Communication Systems Using Signals with Orthogonal Frequency Multiplexing

This paper is devoted to the description of the adaptive modulation method for communication systems using signals with orthogonal frequency-division multiplexing. The present paper describes a method aimed at reducing the number of bit errors in signal transmission at low signal-to-noise ratio in channels with active interference, as well as multipath channels with unstable, rapidly changing characteristics. Reducing the probability of bit errors is one of the main tasks in the design of communication systems, along with increasing the data rate, reducing delay and increasing the number of users. Therefore, finding ways to optimally use the frequency-time resource for data transmission is an urgent task. The presented adaptive modulation technique uses pilot symbols to estimate the data link and compute maximum error vector magnitude. The proposed method made it possible to reduce the probability of a bit error by 15% compared to existing methods. Also, the presented method showed a spectral efficiency 1.5 times greater than the considered methods.