Symbiotic Sensing and Communication: Framework and Beamforming Design

TL;DR

This paper introduces a symbiotic sensing and communication framework that enhances vehicle communication and sensing accuracy through joint beamforming design, utilizing both digital and hybrid array architectures.

Contribution

It proposes a novel SSAC framework with a new beamforming design approach based on CRLB and develops algorithms for both digital and hybrid array systems.

Findings

HAD beamforming outperforms conventional schemes with fewer RF chains.

The algorithms achieve high data rates and accurate localization.

Simulation confirms effectiveness for VUEs and weak targets.

Abstract

In this paper, we propose a novel symbiotic sensing and communication (SSAC) framework, comprising a base station (BS) and a passive sensing node. In particular, the BS transmits communication waveform to serve vehicle users (VUEs), while the sensing node is employed to execute sensing tasks based on the echoes in a bistatic manner, thereby avoiding the issue of self-interference. Besides the weak target of interest, the sensing node tracks VUEs and shares sensing results with BS to facilitate sensing-assisted beamforming. By considering both fully digital arrays and hybrid analog-digital (HAD) arrays, we investigate the beamforming design in the SSAC system. We first derive the Cramer-Rao lower bound (CRLB) of the two-dimensional angles of arrival estimation as the sensing metric. Next, we formulate an achievable sum rate maximization problem under the CRLB constraint, where the channel state information is reconstructed based on the sensing results. Then, we propose two penalty dual decomposition (PDD)-based alternating algorithms for fully digital and HAD arrays, respectively. Simulation results demonstrate that the proposed algorithms can achieve an outstanding data rate with effective localization capability for both VUEs and the weak target. In particular, the HAD beamforming design exhibits remarkable performance gain compared to conventional schemes, especially with fewer radio frequency chains.