Safety Band Testing Plans and Technical Info
V2X Communications for Transportation
This presentation summarizes the current vehicle-to-everything (V2X) ecosystem, including: V2X history, the 5.9 GHz Spectrum (Safety Band), Dedicated Short Range Communications (DSRC), Long-Term Evolution (LTE)-Cellular-V2X, and recent proposed changes to the Safety Band per the Federal Communication Commission’s (FCC’s) Feb. 6, 2020 Notice of Proposed Rulemaking (NPRM).
The United States Government is committed to fostering surface transportation innovations to ensure the United States leads the world in automated vehicle (AV) technology development and integration while prioritizing safety, security, and privacy and safeguarding the freedoms enjoyed by Americans. AV 4.0 presents a unifying posture to inform collaborative efforts in AVs for all stakeholders.
V2X Communications and Interference Testing
This report documents DOT’s exploration of the safety and performance impacts that will occur if revisions to the current 5.9 GHz band allocations are enacted.; our DOT lab findings related to adjacent-channel operations of DSRC, LTE-CV2X, and unlicensed Wi-Fi (UNII) raise questions about safety-of-life critical V2X reliability based on observed interference between devices.
This document presents results tests conducted to baseline the potential impact of cross-channel Wi-Fi (802.11ac) emissions on Dedicated Short Range Communications (DSRC) performance. The tests showed the potential for cross-channel interference affecting DSRC performance at a typical range of 200 to 300 meters. These results are expected to affect LTE-CV2X operations as well.
This document lays out the DOT’s initial a plan to analyze the impact of unlicensed devices on Vehicle-to-Everything (V2X) technology that is currently operating in the 5.9GHz Safety Band, and lists required V2X performance capabilities against which to evaluate proposed band sharing.
This slide deck is an overview of the USDOT’s 5.9 GHz Transportation Safety Band Testing activities that are focused on the criticality of ensuring spectrum availability with no harmful interference. The slides summarize current test plans, test metrics, and test procedures that build from the initial plan, and presents the current test schedule (slide 11).
Analysis of Spectrum Allocation Changes
This brief assessment documents DOT concerns with the FCC’s NPRM: Use of 5.850-5.825 GHz Band [Docket No 19-138]. The assessment highlights the problems that will occur with the proposed reduction in dedicated spectrum for transportation, and the critical technical and financial ramifications for safety, mobility, and future transportation technology advancements.
Analyses of V2X Benefits
This document provides a summary of analytical efforts to estimate the potential benefits and costs of Connected Vehicles and to understand the implications of different deployment scenarios. The specific area of focus was on V2I applications and whether these applications offer enough incremental benefits over a V2V-only approach to warrant the additional expense for roadside infrastructure. The analysis and findings are preliminary.
This report outlines guidance for State and Local agencies on selecting deployment locations for the Vehicle-to-Infrastructure (V2I) application, Curve Speed Warning. The intent of the Curve Speed Warning application is to target crashes on horizontal curves by providing a warning to vehicles approaching the curve at an unsafe speed based on the conditions within the curve.
This report outlines guidance for State and Local agencies on selecting deployment locations for the Vehicle-to-Infrastructure (V2I) application, Stop-Sign Gap Assist (SSGA). The intent of the SSGA application is to target crashes that result from poor gap acceptance at two-way-stop-controlled intersections. SSGA accomplishes this by providing assistance to the driver on the minor road in identifying a suitable gap to travel straight or turn.
This report outlines guidance for State and Local agencies on selecting deployment locations for the Vehicle-to-Infrastructure (V2I) application, Red-Light-Violation Warning (RLVW). The intent of the RLVW application is to prevent crashes due to signal violations at signalized intersections by warning vehicles approaching the intersection that are potentially going to violate the signal based on their approach speeds and distance to the signalized intersection. RLVW accomplishes this by exchanging intersection information (signal phase and timing, geometric design, and GPS location) and vehicle information to then issue a warning to the driver.
Analysis of 2016 Proposed Changes to Existing Out of Band Emissions (OOBE) Adjacent Rules: Adjacent Channel Interference from Unlicensed National Information Infrastructure (UNII) Transmissions into the 5.9 GHz Wireless Access for Vehicular Environment (WAVE) Band
This USDOT analysis examines the changes to the out‐of‐band emission (OOBE) levels on the Dedicated Short Range Communication Service (DSRCS) that supports safety applications in the transportation sector. The Federal Communications Commission (FCC) released a Memorandum of Opinion and Order on March 1, 2016 that has the effect of increasing the OOBE limits for Unlicensed National Information Infrastructure (U‐NII) (FCC Rules Part 15.407) devices operating in the 5725‐5850 MHz band, bringing them more in line with digitally modulated devices (Part 15.247). The impact of these new OOBE levels can have a negative impact on users in adjacent spectrum (5850‐5925 MHz), which is the spectrum allocated for transportation safety. The analysis concludes that the new limits potentially increase interference to DSRC, but the specific level cannot be established without studying specific deployment scenarios and conducting further analysis.
This document presents a structured, technical analysis of re‐channelization, as proposed in the FCC docket by Unlicensed National Information Infrastructure (U‐NII) vendors as of 2017, and identifies the issues associated with this particular mitigation based on current rules. The analysis of the re-channelization approach concludes that there will be a significant, negative degradation of transportation safety communications and the ability to support the range of vehicle‐to‐vehicle (V2V), vehicle-to-infrastructure (V2I), and public safety functions as currently defined. This effect is due to the self‐interference and adjacent channel interference experienced when moving the three channels next to each other in the upper band without any isolation from the U‐NII transmissions. In this new configuration, re‐channelization will significantly affect the ability to transmit and receive the broadcast basic safety messages (BSMs) and other similar messages such as emergency vehicle messages or signal phase and timing (SPaT) information.
This white paper documents the potential for interference in adjacent Safety Band channels and examines a subset of adjacent channel information included in the FCC’s Phase I Testing of Prototype U-NII-4 Devices report. The USDOT examined potential Out-of-Band Emissions (OOBE) interference into the adjacent 10 MHz and 20 MHz channels, the same channels that the FCC has suggested could serve all of transportations low-latency, high availability needs.
This report details the testing and corresponding results from the USDOT’s “baseline” testing of DSRC performance in the presence of unlicensed devices within a real-world setting. The USDOT completed this testing as part of a three-phased effort (this testing was done in parallel with phase 1) in partnership with the Federal Communications Commission (FCC) and the National Telecommunications and Information Administration (NTIA). The USDOT continues to research approaches for efficiently utilizing the 5.9 GHz Safety Band without sacrificing the safety benefits promised by DSRC technology. As part of that effort, the USDOT will build on the findings of this work to move to Phase 2 which will test unlicensed devices with sharing mechanisms that have the potential to allow unlicensed devices to operate alongside DSRC within the 5.9 GHz band.