This work presents an approach for optimization of window coefficients for 5G user equipment side sensing, using orthogonal frequency division multiplexing radar-based range and velocity estimation, based on the sounding reference signal (SRS) from the 5G New Radio (NR) standard. The signal configuration and the corresponding waveform are generated in compliance with the 3rd Generation Partnership Project (3GPP) standard for 5G. The limitations of conventional signal processing for resources available for sensing with the SRS are highlighted. The proposed approach, which optimizes the window coefficients to improve the sensing capabilities, is implemented through two methods. The first method employs a decoupled optimization strategy for range and velocity, showing high computational efficiency. Our results demonstrate that this method significantly improves the peak sidelobe level (PSL) of the velocity profile by over $\mathrm{15}\,\mathrm{dB}$, although it does not address the issue of diagonally located sidelobes, which occur due to non-uniform resource distribution. The second method adopts a comprehensive full 2D optimization technique. While it requires more computational resources and does not improve the PSL beyond the first method’s achievements, it mitigates the diagonally located sidelobes issue. The level of these have been improved by more than $\mathrm{3}\,\mathrm{dB}$.

This paperpresents the measurement procedure as well as the calculations and theoretical background for the estimation of particle sizes with the help of a dual-frequency measurement setup. For the measurement, two fully integrated radar sensors are implemented which offer advantages over typically used technologies at high frequencies. The first sensor has a constant transmitting frequency of 90 GHz while the second sensor offers a possibility to vary the transmitting frequency over the entire D-band with frequencies between 110 and 180 GHz. With these frequencies, different sizes can be determined. The presented approach makes use of the different transitions between the linear increasing Rayleigh scattering regime and the Mie regime. With a fitting indoor measurement setup that resembles an industrial duct, the approach is verified for spheroid glass particles with a diameter of 0.875 mm. The results show a slight deviation from the expected value of particle sizes overall.

This paper presents a comprehensive analysis of interference events in automotive scenarios based on radar systems equipped with communication-assisted chirp sequence (CaCS). First, it examines the impact of interference on radar and communication functionalities in CaCS systems according to the orientation of the investigated nodes. For this purpose, a graph-based approach is employed with MATLAB simulations to illustrate the potential occurrence of interference on the graph for communication functionality compared with their counterparts on radar. Second, the paper delves into the impact of interference on the synchronization between two communicating CaCS nodes. It extends a previous study to match the frequency of current radar sensors, where chirp estimation, an adjusted version of the Schmidl & Cox algorithm, and correlation are adopted to synchronize the transmitter and receiver of two CaCS communicating nodes in the time-frequency plane. The proposed synchronization method is finally verified by measurements at ${79}\,\mathrm{GHz}$ with a system-on-chip, where the resulting correlation metric and mean square error are illustrated as validation factors.

Due to the rising occupancy of the radio spectrum, new strategies for covering the ever increasing amount of data are necessary. This work presents a system for integrating data transmission into a frequency-modulated continuous wave (FMCW) radar by modulating the radar signal with frequency shift keying (FSK). The system offers a high chirp bandwidth of 5 GHz and uses the 60 GHz band. The FSK carrier frequency affects the noise level. A higher frequency leads to a lower noise floor due to 1/f-noise but requires a higher sampling rate. Therefore, 15 MHz was chosen as a compromise. A high data rate allows for a fast data transmission but requires a short chirp time, which leads to a noisier frequency chirp. The radar parameters are also affected by this choice. This leads to a baud rate of 20.8 kbit/s. With a higher order FSK, higher data rates are possible. This proves that the data transmission via FMCW radar signals is possible and a first choice if lower data rates are sufficient, because the hardware effort is comparatively low.