  Joint communication and sensing (JCAS) is a promising technology for 6th
Generation (6G) mobile networks, such as intelligent vehicular networks,
intelligent manufacturing, and so on. Equipped with two spatially separated
antenna arrays, the base station (BS) can perform downlink active JCAS in a
mono-static setup. This paper proposes a Concurrent Downlink and Uplink (CDU)
JCAS system where the BS can use the echo of transmitted dedicated signals for
sensing in the uplink timeslot, while performing reliable uplink communication.
A novel successive interference cancellation-based CDU JCAS processing method
is proposed to enable the estimation of uplink communication symbols and
downlink sensing parameters. Extensive simulation results verify the
feasibility of the CDU JCAS system, showing a performance improvement of more
than 10 dB compared to traditional JCAS methods while maintaining reliable
uplink communication.
