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

Abstract

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, communicationcentric, radar-centric, and joint design and optimization.

Integrated Human Activity Sensing and Communications

“…A communication-and sensing-capable radio emission can simultaneously extract the environmental information, while conveying communication data from the transmitter to the intended receiver(s). Even though a number of signaling strategies are able to achieve a unified sensing and communication waveform, the most straightforward implementation is to reuse the communication infrastructures for wireless sensing, with a low-cost and fast-deployment footprint [6]. To provide a systematic view for the evolution from the communicationonly devices to the ISAC infrastructure, in this section, we introduce a general ISAC receiver signal processing framework by examining the similarities and differences of current communication and sensing signal processing procedures, with reference to the sensing application of HAR.…”

Integrated Sensing and Communications: Towards Dual-functional Wireless Networks for 6G and Beyond

“…Fully unified ISAC waveforms are generally designed following three philosophies, namely, sensing-centric design (SCD), communication-centric design (CCD), and joint design (JD) [48], [53], which we elaborate as follows.…”

“…This leads to severe phase noise in terms of timing offset (TO) and carrier frequency offset (CFO) between the sensing transmitter and receiver, and thereby causes ambiguity in estimating the delay and Doppler frequency of the target. As an example, a clock stability of 20 parts-per-million (PPM) may generate a TO of 20 ns over 1 ms, which leads to ranging error of 6 m [53]. For typical coherent radar signal processing across packets/pulses, the sensing performance will be seriously degraded due to the accumulation of the TO and CFO.…”

SNR Scaling Laws for Radio Sensing with Extremely Large-Scale MIMO

“…There is no doubt that 6G should continue to offer wireless communication as its main service, with significant performance improvement in terms of e.g., coverage, connectivity density, communication rate, etc [1] [2]. In addition, it is also believed that 6G is quite promising to support ubiquitous localization and radar sensing [4]- [6], thanks to the continuous expansion of cellular bandwidth and antenna size that makes highresolution localization and sensing possible. Besides being offered as new services, sensing may also be leveraged to enhance wireless communications [7].…”