Issue link: https://www.e-digitaleditions.com/i/1347119
April/May/June 2021 I 45 TABLE 1: Shows channel assignments for current applications and pending designations. The DSRC uses IEEE 802.11p in the 5.9 GHz band and is specifically designed for automotive use. A dedi- cated spectrum of 75 MHz in the 5.9 GHz band was allocated for ITS, specifically for the development of DSRC. Seven 10 MHz channels have been designated with a 5 MHz band as a buffer to the adjacent bands in the lower frequency. This allocated bandwidth is optimized for maximum cyber security and has a large base of interoperable solu- tions. The DSRC technology has been standardized and widely tested for V2I, V2V, and V2X applications for more than a decade. The OBU allows CAV vehicles to communicate with other CAV vehicles, as well as the electronics at the RSU poles (the CAV infrastructure). Through the OBU, DSRC broadcasts basic information, such as location, heading, and speed to the surrounding vehicles and infrastructure 10 times every second in a secure anonymous manner. Surrounding RSUs will receive this data and respond with broadcast for travel information messages (TIMs) and RSMs. Safety-related messages on limited access highways include curve speed warning, reduced speed warning/lane closure, and ramp wrong way warnings. Safety-related messages for local and urban streets will include red-light violation warning, pedestrian crosswalk warning, and railroad crossing warning. Surrounding vehicles receiving the message from the transmitting vehicle will estimate any risk through collision avoidance and other safety applications. Driver privacy is maintained during transfer of information with no unique data about the vehicle included. All three RSU units meet the U.S. Department of Transportation FHWA 4.1 specification for commu- nications to vehicles, data security, and GPS reception for time of day and location. 8 Currently, most of the electronics have been installed in the ITS cabinets. Ohio Department of Transportation technicians are working with the RSU system integrators to test and resolve any equip- ment issues; equipment includes the RSU antennas on the 61 poles and the network electronics in the ITS cabinets. This trouble-shooting and system startup will be completed or near completion at the time of this article. Virtual guard band from UNII-3 below Time-critical safety-of-life and property applications; e.g., V2V safety, situational awareness, intersection safety Public safety or government applications only; e.g., emergency vehicle signal pre-emption, other public safety, public transit e.g, I2V safety mobility & non- priority applications* e.g. vulnerable road user & security communications* e.g., future V2X safety, security, mobility & non- priority applications* e.g., future V2X safety, security, mobility & non- priority applications* WAVE Short Message Protocol (WSMP) braodcast only; service advertisements, broadcast-based services with minimal bandwidth requirements Flexible assignment to promote spectral efficiency support application priorities and prevent adjacent channel interference; dynamic assignment by control channel Flexible assignment to promote spectral efficiencym support application priorities and prevent adjacent channel interference; dynamic assignment by control channel 5.850 GHz 5.925 GHz 5850-5855 reserve 5 MHz CH172 service 10 MHz CH175 CH181 CH174 service 10 MHz CH176 service 10 MHz CH178 service 10 MHz CH180 service 10 MHz CH182 service 10 MHz CH184 service 10 MHz * Flexible channel assignment examples per SAE J2945/0 Source: FCC Report and Order FCC 03-324