  Listen-Before-Talk (LBT) has been adopted as the spectrum sharing technique
that guarantees a fair LTE/Wi-Fi coexistence in the unlicensed spectrum at the
5 GHz band. Differently, at mmWave bands, where beamforming is a must to
overcome propagation limits, LBT scope becomes limited because the interference
layout changes due to the directionality of transmissions. In this regard, this
paper proposes a Listen-Before-Receive (LBR) technique for shared spectrum
access and analyzes its potentials to promote a fair coexistence of multiple
Radio Access Technologies (RATs) in unlicensed mmWave bands, as, e.g., 5G New
Radio (NR) access technology and Wireless Gigabit (WiGig) devices using IEEE
802.11ad/ay standard. Since the less likely but still harmful interference
situations with directional transmissions can no longer be detected easily at
the transmitter, we believe that the receiver has useful information to be
used. The main idea of LBR is that we provide to the receiver a say when it
comes to allowing/preventing the access to the channel. In this line, we
propose potential implementations of LBR, in conjunction with LBT and the
self-contained slot, for NR-based access to unlicensed mmWave bands.
