transmitters

A simple frequency-domain negative acknowledgment feedback for automatic repeat on reQuest underwater acoustic networks

Bidirectional underwater acoustic communications usually request the transmission of some control information among nodes to govern the data flow. Control signaling, employed as frame reception validation, is also a peculiarity of the Automatic Repeat on reQuest (ARQ) schemes. An alternative solution to the error control problem is using forward error correction, even though high redundancy is needed to obtain the low error rate, hence leading to a sensible throughput reduction. Furthermore, no control on data integrity is allowed.

Multistatic GNSS-based passive radar for maritime surveillance with long integration times. Experimental results

The focus of this paper is on multi-transmitter GNSS passive radar for maritime surveillance. Particularly, working in the range-Doppler domain, the possibility to integrate over long time intervals (required to counteract restricted power budget provided by navigation satellites) the returns from a moving target illuminated by multiple GNSS transmitters is experimentally demonstrated.

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