Adaptive frequency-hopping in HF communications

In the presence of the severe frequency selective fading due to ionospheric multi-path propagation and the abundance of interference from other users, the HF communication quality can be decreased drastically. The combination of adaptive frequency-hopping scheme and HF communication improves system throughput effectively. However, the traditional adaptive frequency-hopping can not satisfy the increased need of communication. As more and more traffic get the system afforded, the frequency collision and other hostile jamming make the communication more hard than before. The paper summarizes some new techniques for enhancement; they aim to solve problems such as the intense spectrum, frequency collision and so on.