Research on Adaptive Digital Communication Lines with Decision Feedback

Problem Statement. The advancement of efficient digital radio communication systems necessitates the development of methods that enhance both their energy and spectral efficiency. One approach to addressing this challenge involves assessing the state of the communication channel and selecting optimal modulation schemes within a digital transmission system equipped with feedback. The aim of this study is to investigate modern coding and modulation techniques applicable to feedback channels. The paper proposes methods for integrating these techniques into an adaptive feedback system in order to achieve optimal spectral and energy efficiency. Methods. A comparative analysis of various design approaches for adaptive feedback systems was conducted through simulation in the MATLAB environment. The simulations accounted for the influence of different types of noise on the data transmission process within feedback channels. Scientific Novelty. The novelty of this work lies in its comprehensive investigation and comparative analysis of contemporary coding methods and multi-level modulation techniques. Furthermore, the study presents recommendations for their effective application in adaptive communication systems. Results. As a result of this research, an adaptive data transmission system with feedback was developed. This system achieves higher data transmission rates compared to non-feedback systems, while still meeting the reliability requirements of the communication channel. Practical Significance. The proposed solution is recommended for scenarios that demand high data transmission reliability alongside high throughput. This is particularly relevant under conditions of poor signal quality, which may arise due to significant environmental interference such as in fading channels.