Toyota Raises Concerns About Wi-Fi in 5.9 GHz Band

Toyota raised concerns about the testing process on sharing between anti-crash, dedicated short-range communications (DSRC) systems being deployed by automakers and Wi-Fi in the 5.9 GHz band. The FCC has been testing 5.9 GHz Wi-Fi devices since the summer with an eye toward sharing (see 1608010044). Toyota officials filed in docket 13-49 on meeting with Office of Engineering and Technology Chief Julius Knapp and others from OET. There are “clear limitations to the testing that can be accomplished with the re-channelization prototype devices that have been supplied,” the company said. “The re-channelization devices submitted for testing do not fully support the re-channelization proposal because they do not implement any sharing mechanism for the portion of the band that is expected to be shared between U-NII [unlicensed] and DSRC. As a result, while the devices can be used to test cross-channel interference from U-NII to DSRC, they cannot be used to test co-channel U-NII-to-DSRC interference.” DSRC would suffer if the 5.9 GHz band is rechannelized and safety systems restricted to the upper 30 MHz, as some Wi-Fi advocates urge, Toyota said. “DSRC communications in the overlapping portion of the band would be required to use 20 MHz channels, which has been shown to be inferior to 10 MHz channels for DSRC services.” A Wi-Fi advocate countered the Toyota arguments. “The auto industry continues to suggest that the use of DSRC for safety-of-life will stretch across all of the seven 10 MHz channels,” said Michael Calabrese, director of New America’s Wireless Future Project. “In reality, even if the Trump administration decides to impose this $10 billion vehicle-to-vehicle DSRC mandate on consumers, the Department of Transportation’s rule requires that all time-critical V2V safety signaling use a single, dedicated 10 MHz channel. Automakers hope to use the remainder of the band for display advertising and other commercial use that can readily share with Wi-Fi. The only issue is whether the safety channel should be moved to exclusive-use spectrum at the top of the band, which would promote both safety and shared use.”