Tady je k tomu paper: https://www.nctatechnicalpapers.com/Paper/2016/2016-full-duplex-docsis-technology-over-hfc-networks
Na strane modemu podle vseho frekvencne deleny multiplex s tim, ze frekvence odesilani i prijimani obsahne cely podporovany pasmo (aktualne do 1,2 GHz).
Na strane CMTS pak prijimac se schopnosti odecteni signalu odeslaneho vysilacem (sebou) a tim ziskani signalu odeslaneho modemem.
Podobna technologie mimochodem existuje ve fazi vyzkumu/vyvoje i pro LTE: https://www.extremetech.com/extreme/187190-full-duplex-a-fundamental-radio-tech-breakthrough-that-could-double-throughput-alleviate-the-spectrum-crunch