VEHICULAR RADIO ACCESS TO UNLICENSED SPECTRUM

Connection to/among vehicles has been bound to one of the dominant wireless use cases in the upcoming decade. To support the booming applications, scarce bandwidth allocated for vehicle connection has become a performance bottleneck and rigidifies further evolution of future technologies. This concern consequently drives the utilization of unlicensed spectrum with ample bandwidth, on which communications nevertheless should comply with regulatory requirements such as listen-before-talk, which results in unique challenges. For next generation vehicular radio access to unlicensed spectrum, in this article, we develop dual designs to inherit the distinct engineering spirits of 3GPP LTE and IEEE 802.11ax. The proposed LTE-based vehicular radio access should integrate 3GPP vehicle-to-everything connection, licensed assisted access, and device-todevice proximity services to address the particular issues of sidelink shared channel collision and resource uncertainty on uplink, downlink, and sidelink. The proposed IEEE 802.11ax-based vehicular direct radio access emphasizes providing a qualityof-service-guaranteed sidelink access scheme to enable direct vehicle data exchange. The proposed designs pave a foundation to deploy vehicle-to-everything in unlicensed spectrum.