  The integration of sensing and communication (ISAC) functionalities have
recently gained significant research interest as a hardware-, power-, spectrum-
and cost- efficient solution. This experimental work focuses on a
dual-functional radar sensing and communication framework where a single
radiation waveform, either omnidirectional or directional, can realize both
radar sensing and communication functions. We study a trade-off approach that
can balance the performance of communications and radar sensing. We design an
orthogonal frequency division multiplexing (OFDM) based multi-user multiple
input multiple output (MIMO) software-defined radio (SDR) testbed to validate
the dual-functional model. We carry out over-the-air experiments to investigate
the optimal trade-off factor to balance the performance for both functions. On
the radar performance, we measure the output beampatterns of our transmission
to examine their similarity to simulation based beampatterns. On the
communication side, we obtain bit error rate (BER) results from the testbed to
show the communication performance using the dual-functional waveform. Our
experiment reveals that the dual-functional approach can achieve comparable BER
performance with pure communication-based solutions while maintaining fine
radar beampatterns simultaneously.
