Time-division approach in HF wideband: Surfing the wave to offer a better performance

HF ionospherical channels are very challenging due to their time and frequency selective, and highly varying natures. Furthermore, they offer only limited data rates, which led generations of engineers to limit the signalization information and to reduce the number of turnarounds to preserve a maximum throughput for useful data. However, new wideband modems [1] [2] have recently been proposed, that achieve much higher data rates and a much better resilience on the HF link, leading to re-assess such traditional strategies. This paper presents a protocol relying on a time division approach, which can follow very closely the channel variations between two stations for only a limited signaling overhead, and as such allows to optimize the transmissions. Experimental results are given, that demonstrate the interest of such an approach over various ionospherical HF channels.