Multibeam for Joint Communication and Radar Sensing Using Steerable Analog Antenna Arrays

Abstract

Beamforming has great potential for joint communication and sensing (JCAS), which is becoming a demanding feature on many emerging platforms such as unmanned aerial vehicles and smart cars. Although beamforming has been extensively studied for communication and radar sensing respectively, its application in the joint system is not straightforward due to different beamforming requirements by communication and sensing. In this paper, we propose a novel multibeam framework using steerable analog antenna arrays, which allows seamless integration of communication and sensing. Different to conventional JCAS schemes that support JCAS using a single beam, our framework is based on the key innovation of multibeam technology: providing fixed subbeam for communication and packetvarying scanning subbeam for sensing, simultaneously from a single transmitting array. We provide a system architecture and protocols for the proposed framework, complying well with modern packet communication systems with multicarrier modulation. We also propose low-complexity and effective multibeam design and generation methods, which offer great flexibility in meeting different communication and sensing requirements. We further develop sensing parameter estimation algorithms using conventional digital Fourier transform and 1D compressive sensing techniques, matching well with the multibeam framework. Simulation results are provided and validate the effectiveness of our proposed framework, beamforming design methods and the sensing algorithms. 2 protocols, a BF design methodology, multibeam generation and updating algorithms, and sensing algorithms, to achieve large field-of-view (range in directions), flexible and accurate sensing with controllable and insignificant compromise on communication performance.Our main contributions in this paper are as follows, with a focus on multibeam with two subbeams:• We propose a system architecture and protocols for implementing multibeam JCAS technology, with the use of two analog arrays. The two arrays, spatially widely separated, are introduced mainly to suppress leakage signal from the transmitter to receiver, so that the receiver can work all the time, transiting between communication and sensing modes. The proposed framework fully complies with a conventional time division duplex (TDD) communication system and reuses the TDD timeslot. This is detailed in Section II; • We provide a BF design methodology to enable the integration of beam-scanning based sensing with fixedbeam based communication functions. We also present a generalized Least Squares (LS) BF solution for generating beams with desired shape. This is discussed in Section III; • Detailed methods for generating and updating multibeam BF vectors are developed. The methods offer flexibility in meeting different and time-varying requirements for communication and sensing, capability in constructively combining communication and sensing subbeams for communication purpose, and simplicity in updating BF vectors. The details are presented in Section IV...

Joint radar and communication: A survey

“…For communication, it is capable to improve the transmission rate as well as the SINR through the spatial freedom of transceiver antennas. For radars, the MIMO techniques can extend the size of virtual aperture effectively and achieve multi-beam operating for multiple targets searching, locating and tracking [168]. Ultimately, MIMO radar has the unique advantages of spatial diversity and waveform diversity, which can effectively alleviate fading, improve resolution and suppress interference.…”

Beamformer Design and Optimization for Full-Duplex Joint Communication and Sensing at mm-Waves

“…While beamforming techniques have been extensively studied over the past decades for communications at large, some recent works have proposed new beamforming designs to satisfy the additional requirements stemming from the JCAS operation specifically. In [24], [25], the so-called multibeam approach using steerable analog antenna arrays is identified as one of the main enablers for mm-wave JCAS systems. The proposed multibeam scheme provides separate controllable beams for communication and sensing with different design requirements.…”

“…Then, similar to [24], [27], [39], the communication and sensing weights are combined coherently. Considering the U communication beams and a single sensing beam, all coexisting simultaneously, the combined TX weights can be expressed as…”

Angle-of-Arrival Acquisition and Tracking via Virtual Subarrays in an Analog Array

“…We can then choose the vector with the coverage range larger than and closest to the desired one. When the pointing direction needs to be changed, we can multiply a linear phase shifting sequence to the selected BF vector, to shift the BF pointing direction from zero degree to the centre of the desired one [7]. The shifted BF vector is then used as w 1 (t) .…”