Joint Millimeter-Wave Communication and Radar for Automotive Applications

DTRT13-G-UTC58Automotive joint communication and radar (JCR) waveforms with fully digital baseband generation and processing can now be realized at the millimeter-wave (mmWave) band. Prior work has developed a mmWave wireless local area network (WLAN)-based automotive JCR that exploits the WLAN preamble for radars. The performance of target velocity estimation, however, was limited. In this paper, we propose an adaptive virtual JCR waveform design for automotive applications at the mmWave band. The proposed system transmits a few non-uniformly placed preambles to construct several receive virtual preambles for enhancing velocity estimation accuracy, at the cost of only a small reduction in the communication data rate. We evaluate JCR performance trade-offs using the Cramer- Rao Bound (CRB) metric for radar estimation and a novel distortion minimum mean square error (MMSE) metric for data communication. Additionally, we develop three different MMSE-based optimization problems for the adaptive JCR waveform design. Simulations show that an optimal virtual (non-uniform) waveform achieves a significant performance improvement as compared to a uniform waveform. For a radar CRB constrained optimization, the optimal radar range of operation and the optimal communication distortion MMSE (DMMSE) are improved. For a communication DMMSE constrained optimization with a high DMMSE constraint, the optimal radar CRB is enhanced. For a weighted MMSE average optimization, the advantage of the virtual waveform over the uniform waveform is increased with decreased communication weighting. Comparison of MMSE-based optimization with traditional virtual preamble count-based optimization indicated that the conventional solution converges to the MMSE- based one only for a small number of targets and a high signal-to-noise ratio

Radar Imaging Based on IEEE 802.11ad Waveform in V2I Communications

Since most of vehicular radar systems are already exploiting millimeter-wave (mmWave) spectra, it would become much more feasible to implement a joint radar and communication system by extending communication frequencies into the mmWave band. In this paper, an IEEE 802.11ad waveform-based radar imaging technique is proposed for vehicular settings. A roadside unit (RSU) transmits the IEEE 802.11ad waveform to a vehicle for communications while the RSU also listens to the echoes of transmitted waveform to perform inverse synthetic aperture radar (ISAR) imaging. To obtain high-resolution images of the vehicle, the RSU needs to accurately estimate round-trip delays, Doppler shifts, and velocity of vehicle. The proposed ISAR imaging first estimates the round-trip delays using a good correlation property of Golay complementary sequences in the IEEE 802.11ad preamble. The Doppler shifts are then obtained using least square estimation from the echo signals and refined to compensate phase wrapping caused by phase rotation. The velocity of vehicle is determined using an equation of motion and the estimated Doppler shifts. Simulation results verify that the proposed technique is able to form high-resolution ISAR images from point scatterer models of realistic vehicular settings with different viewpoints. The proposed ISAR imaging technique can be used for various vehicular applications, e.g., traffic condition analyses or advanced collision warning systems

IEEE 802.11ad V2V-radar : a joint vehicle-to-vehicle communication and automotive radar system

Proprietary millimeter wave (mmWave) radar technologies are widely used in luxury cars to enable active safety functions such as cruise control and collision avoidance. Vehicle-to-vehicle (V2V) communication using the dedicated short range communication (DSRC) technology permits basic low-latency safety applications such as forward collision detection in the 5.9 GHz band. The DSRC technology supports only low data rates, which is not sufficient to handle the gigabytes that can be generated in the next generation vehicles. This challenge can, however, be overcome by using mmWave V2V communication technology that has not been adopted yet by the automotive industry. In this thesis, we propose an IEEE 802.11ad V2V-radar system that leverages the waveform and the typical receiver algorithms of a mmWave consumer WLAN standard to enable a joint framework of vehicular communication and radar technologies at 60 GHz. It will lead to efficient spectrum usage, enhanced performance and increased penetration in the vehicles with minimal size and cost of the hardware. Our theoretical analyses and numerical simulations show promising results; Gbps data rate is achieved simultaneously with cm-level range accuracy, cm/s-level velocity accuracy and high probability of detection at a significantly low false alarm rate.Electrical and Computer Engineerin

An Overview of Signal Processing Techniques for Joint Communication and Radar Sensing

Joint communication and radar sensing (JCR) represents an emerging research field aiming to integrate the above two functionalities into a single system, by sharing the majority of hardware, signal processing modules and, in a typical case, the transmitted signal. The close cooperation of the communication and sensing functions can enable significant improvement of spectrum efficiency, reduction of device size, cost and power consumption, and improvement of performance of both functions. Advanced signal processing techniques are critical for making the integration efficient, from transmission signal design to receiver processing. This paper provides a comprehensive overview of the state-of-the-art on JCR systems from the signal processing perspective. A balanced coverage on both transmitter and receiver is provided for three types of JCR systems, namely, communication-centric, radar-centric, and joint design and optimization