Ordinary amateur radio Packet Radio is not well adapted to the characteristics of the HF range.
A new, robust variant of this mode has features, which attempt to mitigate these characteristics. Robust Packet is a data transmission mode designed by Special Communications Systems.
It is optimized for deployment in the short wave band. To accommodate the characteristics of this frequency range, for example fading and multipath propagation (intersymbol interference), eight carrier, pulse shaped OFDM (Orthogonal Frequency Division Multiplex) is used.