[论文解读] Joint Radar and Communication Design: Applications, State-of-the-art, and the Road Ahead

Fan Liu, Christos Masouros+3 more|arXiv (Cornell University)|Jun 3, 2019

Radar Systems and Signal Processing参考文献 103被引用 26

一句话总结

本文提出了一种用于毫米波双功能雷达-通信（DFRC）基站的混合模拟-数字波束成形架构，实现了目标检测与用户设备通信的同步进行。通过利用全向导频信号和连续干扰消除技术，系统在恒包 envelope 和功率约束下实现了对目标的联合波束成形与信道预均衡，仿真结果验证了雷达与通信功能的有效共存。

ABSTRACT

In this paper, we firstly overview the application scenarios and the research progress in the area of communication and radar spectrum sharing (CRSS). We then propose a novel transceiver architecture and frame structure for a dual-functional radar-communication (DFRC) base station (BS) operating in the millimeter wave (mmWave) band, using the hybrid analog-digital (HAD) beamforming technique. We assume that the BS is serving a multi-antenna aided user equipment (UE) operating in a mmWave channel, which in the meantime actively detects multiple targets. Note that part of the targets also play the role of scatterers for the communication signal. Given this framework, we propose a novel scheme for joint target search and communication channel estimation relying on the omni-directional pilot signals generated by the HAD structure. Given a fully-digital communication precoder and a desired radar transmit beampattern, we propose to design the analog and digital precoders under non-convex constant-modulus (CM) and power constraints, such that the BS can formulate narrow beams towards all the targets, while pre-equalizing the impact of the communication channel. Furthermore, we design an HAD receiver that can simultaneously process signals from the UE and echo waves from the targets. By tracking the angular variation of the targets, we show that it is possible to recover the target echoes and mitigate the potential interference imposed on the UE signals by invoking the successive interference cancellation (SIC) technique, even when the radar and communication signals share the equivalent signal-to-noise ratio (SNR). The feasibility and the efficiency of the proposed approaches in realizing DFRC are verified via numerical simulations. Finally, our discussions are summarized by overviewing the open problems in the research field of CRSS.

研究动机与目标

• 通过在共享的毫米波频段中实现雷达与通信的联合运作，缓解频谱拥塞问题。
• 设计一种统一的硬件平台，支持感知与通信双重功能。
• 开发一种收发器架构，能够同时实现目标检测与用户设备通信。
• 利用连续干扰消除（SIC）技术，减轻雷达回波与通信信号之间的干扰。
• 在恒包 envelope 和功率约束下，优化模拟与数字预编码器，以实现对多个目标的波束成形。

提出的方法

• 为工作在毫米波频段的DFRC基站设计了一种混合模拟-数字（HAD）波束成形架构。
• 利用HAD结构生成的全向导频信号，实现对目标的联合搜索与信道估计。
• 在非凸的恒包 envelope 和总功率约束下，优化模拟与数字预编码器，以形成指向目标的窄波束。
• 集成一种HAD接收机，能够同时处理用户设备的通信信号和雷达目标的回波信号。
• 利用目标的角域变化跟踪，实现连续干扰消除（SIC），以恢复回波信号并抑制干扰。
• 对有效信道矩阵进行奇异值分解（SVD），推导在单位阵和功率约束下的最优预编码器解。

实验结果

研究问题

• RQ1 如何使单个毫米波基站通过共享硬件与频谱，高效支持通信与雷达感知？
• RQ2 何种波束成形设计可在恒包 envelope 约束下，实现对目标的同步跟踪与通信信道预均衡？
• RQ3 当雷达与通信信号的信噪比相当时，如何减轻雷达回波引起的干扰？
• RQ4 连续干扰消除在实现雷达与通信信号共存于同一带宽中起到何种作用？
• RQ5 系统如何在满足雷达波束图要求和通信服务质量的前提下，保持高谱效？

主要发现

• 所提出的HAD波束成形设计在恒包 envelope 和功率约束下，成功实现了对多个目标的窄波束成形，并完成了通信信道的预均衡。
• 数值仿真验证了该毫米波频段下雷达与通信系统联合运作的可行性与高效性。
• 连续干扰消除（SIC）技术可有效恢复目标回波，即使雷达与通信信号经历相同的信噪比。
• 系统通过HAD结构生成的全向导频信号，实现了联合目标检测与信道估计。
• 通过有效信道矩阵的SVD分解，推导出最优数字预编码器，确保了单位阵结构和通信域中的干扰零陷。
• 所推导的解满足非凸的恒包 envelope 约束，且确保通信信号对雷达回波的干扰被完全抑制。