The Research On Real-time Channel Evaluation In Adaptive HF Maritime Communication System

This paper introduces the history and principles of the Real-time Channel Evaluation (RTCE), discusses its key technologies, introduces some communication systems in the application of RTCE, and predicts its dominant status in the future HF communications. RTCE is based on forecasting the inherent vulnerabilities to propagation of HF time-varying channel, including multipath delay, Doppler spread, selective fading, interference, so this paper also introduces characteristics of HF channel in the beginning.Familiar RTCE systems all adopt envelope method that Bello brought forward. MTCEM (Multi-Tone Envelope Method) can accurately forecast performance parameters on a set of stored channel and directly decide usable frequency choice. As HF channel characteristic is closed to Gauss, MTCEM may be simplified to multi-tone envelope method RTCE system. For certain user's request and link status, double tone complex envelope method RTCE, double tone envelope RTCE, adaptive HF channel sounding and communication system, all that can easily derived from MTCEM.Application of RTCE in adaptive HF maritime communication system, can improve quality of communication and enhance link rate of communication. The reason choice that realizes RTCE function in adaptive HF maritime communication system, is to measure signal noise rate, multipath delay and Doppler spread by MTCEM.