Communication and sensing are two important features of connected and autonomous vehicles (CAVs). In traditional vehicle-mounted devices, communication and sensing modules exist but in an isolated way, resulting in a waste of hardware resources and wireless spectrum. In this paper, to cope with the above inefficiency, we propose a vehicular behavior-aware integrated sensing and communication (VBA-ISAC) beamforming design for the vehicle-mounted transmitter with multiple antennas. In this work, beams are steered based on vehicular behaviors to assist driving and meanwhile provide spectral-efficient uplink data services with the help of a roadside unit (RSU). Specifically, we first predict the area of interest (AoI) to be sensed based on the vehicles' trajectories. Then, we formulate a VBA-ISAC beamforming design problem to sense the AoI while maximizing the spectral efficiency of uplink communications, where a trade-off factor is introduced to balance the communication and sensing performance. A semi-definite relaxation-based beampattern mismatch minimization (SDR-BMM) algorithm is proposed to solve the formulated problem. To reduce the hardware cost and power consumption, we further improve the proposed VBA-ISAC beamforming design by introducing the hybrid analog-digital (HAD) structure. Numerical results verify the effectiveness of VBA-ISAC scheme and show that the proposed beamforming design outperforms the benchmarks in both spectral efficiency and radar beampattern.

翻译：通信与感知是网联自动驾驶车辆的两项重要功能。传统车载设备虽具备通信与感知模块，但两者相互独立，导致硬件资源与无线频谱的浪费。针对上述低效问题，本文提出一种面向多天线车载发射机的车辆行为感知集成传感与通信波束赋形设计。在该研究中，波束依据车辆行为进行定向调整，在辅助驾驶的同时，借助路侧单元提供高频谱效率的上行数据传输服务。具体而言，我们首先基于车辆轨迹预测待感知区域；随后，构建车辆行为感知集成传感与通信波束赋形优化问题，在感知待感知区域的同时最大化上行通信频谱效率，并引入权衡因子以平衡通信与感知性能。针对上述问题，提出一种基于半定松弛的波束方向图失配最小化算法。为降低硬件成本与功耗，进一步引入混合模数结构对波束赋形设计进行改进。数值结果验证了所提方案的有效性，并表明所设计的波束赋形在频谱效率与雷达波束方向图方面均优于基准方案。