Array processing without any space diversity: application in the HF band (3-30 MHz)

The paper presents an operational system of digital transmission within the HF frequency range, aiming at a significant increase of the data transfer rate compared with the current standard. Therefore, an array processing method performs with a set of four collocated sensors, the spatial responses of which are different one from each other. This diversity induces a well-conditioned problem of spatio-temporal equalization which tends to reduce the effect of multipath interference. The implemented method resorts to a classical LMS algorithm involving training sequences. Several waveforms have been tested and the experimental results reach the expected goal as the data transfer rate increases up to 15 kbits/s in a bandwidth of 3 kHz.