Coexistence of unlicensed devices with DSRC systems in the 5.9 GHz ITS band

With the release of FCC NPRM 13-22 (Docket 13-49), the United States Federal Communications Commission has proposed allowing unlicensed devices such as Wi-Fi to share the 5.9 GHz ITS band, which is currently allocated for DSRC. This proposal, which would create a new set of rules for the band that would become U-NII-4, requires the unlicensed devices to recognize the existence of DSRC systems and defer to them, since DSRC would remain as a co-primary user of the band. This paper examines the issues surrounding U-NII-4 band sharing, reports on industry activities that are trying to balance the needs of the market segments that intend to use the band, discusses some initial ideas for how band sharing could work that adequately protect DSRC, and looks at future work that needs to be done that will adequately inform regulators about the feasibility and practicality of sharing the 5.9 GHz ITS band.