Can Automotive Radars Form Vehicular Networks?

Radar communications (RadCom) is a spectrally efficient way for removing automotive radar interference and thereby enhancing reliable radar sensing, via a single hardware for both radar and communications. When interference coordination does not use all the RadCom resources, opportunities for communicating additional data arise. We propose a new communication protocol, termed RadNet (for radar network), which forms a vehicular ad-hoc multi-hop network by automotive radars in a distributed manner. Simulation results obtained for high-way use cases show that RadNet can enable several Mbps data links without degrading the radar performance

Stepped-Carrier OFDM V2V Resource Allocation for Sensing and Communication Convergence

Stepped-carrier orthogonal frequency division multiplexing (OFDM) radar is a promising low-cost alternative to conventional OFDM radar for automotive applications due to its capability to provide high resolution with low-rate analog to-digital converters (ADCs). In this paper, we investigate centralized time-frequency resource allocation strategies in vehicular networks for vehicle-to-vehicle (V2V) sidelinks employing stepped-carrier OFDM waveform for joint radar sensing and communications. To quantify radar-communication performance trade-offs, we formulate a nonlinear integer programming problem for weighted optimization of radar accuracy and communication spectral efficiency, and perform Boolean relaxation to obtain an efficiently solvable convex program. Simulation results demonstrate radar-optimal and communication-optimal operation regimes, providing insights into time-frequency weightings along the trade-off curve

A Solution for Removing Automotive Radar Interference: Radar Communications

Automotive radar is becoming an indispensable equipment in modern cars, for different functions including lane keeping,speed control and parking, especially due to its immunity to bad weather conditions [1]. Likewise, vehicle-to-vehicle(V2V) communication is on the way to become a standard, having proven its value in dissemination of safety critical information[2]. However, the widespread use of both technologies lead to problems, cutting short future plans for autonomousdriving and safety. Increased penetration rate and density of automotive radars lead to increased mutual interference, whichin turn result with reduced detection probability and ghost detections [3]. Similarly, Omni-directional V2V communicationtransmissions result in high interference with an increased number of vehicles [4]. This interference leads to packet losses,especially in emergency situations when many vehicles emit warning messages, in turn affecting system-wide safety

Distributed Radar-aided Vehicle-to-Vehicle Communication

Establishing high-rate vehicle-to-vehicle (V2V) linkswith narrow beamwidth is challenging due to the varying networktopology. A too narrow beam may miss the intended receiver,while a too broad beam leads to SNR loss. We propose toharness the high accuracy of radar detections to establish V2V links. In particular, we develop a distributed method where eachvehicle associates local radar detections with GPS informationcommunicated by nearby vehicles. The method relies on thetransformation of relative to global coordinates, the definition ofa suitable metric, and solving an optimal assignment problem. Wedemonstrate that the proposed approach avoids time-consumingchannel estimation and provides high SNR, under the conditionthat reliable relative and absolute location information is present

RadChat: Spectrum Sharing for Automotive Radar Interference Mitigation

In the automotive sector, both radars and wireless communication are susceptible to interference. However, combining the radar and communication systems, i.e., radio frequency (RF) communications and sensing convergence, has the potential to mitigate interference in both systems. This article analyses the mutual interference of spectrally coexistent frequency modulated continuous wave (FMCW) radar and communication systems in terms of occurrence probability and impact, and introduces RadChat, a distributed networking protocol for mitigation of interference among FMCW based automotive radars, including self-interference, using radar and communication cooperation. The results show that RadChat can significantly reduce radar mutual interference in single-hop vehicular networks in less than 80 ms

Improved Pedestrian Detection under Mutual Interference by FMCW Radar Communications

The widespread of automotive radars leads to increase of mutual interference, which in turn degrades road safety. The effect of mutual interference with a focus on detection of pedestrians is investigated. It is shown that detection of pedestrians degrades in the presence of mutual interference. A joint radar communication solution is proposed that increases pedestrian detection probability with negligible impact in the ranging error

Radar Communications: A solution for mitigating automotive radar interference

Radar communications based distributed medium access control technique is proposed, which is applicable for FMCW-based automotive radar equipped vehicular ad-hoc networks

Synchronization-free radchat for automotive radar interference mitigation

Automotive radar interference mitigation is expected to be inherent in all future ADAS and AD vehicles. Joint radar communications is a candidate technology for removing this interference by coordinating radar sensing through communication. Coordination of radars requires strict time synchronization among vehicles, and our formerly proposed protocol (RadChat) achieves this by a precise absolute time, provided by GPS clocks of vehicles. However, interference might appear if synchronization among vehicles is lost in case GPS is spoofed, satellites are blocked over short intervals, or GPS is restarted/updated. Here we present a synchronization-free version of RadChat (Sync-free RadChat), which relies on using the relative time for radar coordination, eliminating the dependency on the absolute time provided by GPS. Simulation results obtained for various use cases show that Sync-free RadChat is able to mitigate interference without degrading the radar performance

Comparison of Automotive FMCW and OFDM Radar Under Interference

Automotive radars are subject to interference in spectrally congested environments. To mitigate this interference, various waveforms have been proposed. We compare two waveforms (FMCW and OFDM) in terms of their radar performance and robustness to interference, under similar parameter settings. Our results indicate that under proper windowing both waveforms can achieve similar performance, but OFDM is more sensitive to interference

Radar Interference Mitigation for Automated Driving: Exploring Proactive Strategies

Autonomous driving relies on a variety of sensors, especially on radars, which have unique robustness under heavy rain/fog/snow and poor light conditions. With the rapid increase of the amount of radars used on modern vehicles, where most radars operate in the same frequency band, the risk of radar interference becomes a compelling issue. This article analyses automotive radar interference and proposes several new approaches, which combine industrial and academic expertise, toward the path of interference-free autonomous driving