A RadBackCom Approach to Integrated Sensing and Communication: Waveform Design and Receiver Signal Processing

新兴的物联网（IoT）和感知移动的网络被设想为在大量连接的用户/设备之间提供宽带连接和无处不在的感测能力。集成通信和传感（ISAC）架构通过仅包含一个有源无线电发射机和两个不同的接收链来实现通信和传感之间的频谱共享，以适应这两种功能。另一方面，用于实现低功率和低成本通信的有前景的技术是环境反向散射通信（ABC），其中通常不连接到电池或电网的标签可以通过简单地反射和调制由现有传统系统的射频（RF）发射器发射的入射环境信号来向读取器递送消息。该项目解决了一个新的ISAC架构，称为RadBackCom系统，其中包括一个传统的雷达系统，和一个后向散射通信系统的载波信号是雷达杂波回波的各个设计方面。这项研究将显著推进ISAC和ABC领域的最新技术。实际应用案例可能包括利用地面雷达进行空中/道路交通管制、环境/天气监测、防撞、入侵检测和无线电成像。具体而言，当遗留系统是纯雷达系统或双功能雷达通信（DFRC）系统时，将开发数据传输方案。当有多个标签传输数据时，将开发用于基于导频的源系统和无导频的无源系统的收发器方案。此外，当传统系统的反射智能表面（RIS）的帮助下，几种情况下，将被认为是RIS也扮演的角色的信息承载标签，一位读者，和一个助手，分别在RadBackCom系统，和相应的解决方案将被开发。提出的方法利用了一系列先进技术，包括压缩感知、低秩处理、基于模拟的优化、代数编码理论、迭代解码和深度神经网络，将为ISAC和ABC的理论和应用带来重大创新。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The emerging Internet of Things (IoT) and perceptive mobile networks are envisioned to provide broadband connectivity among a sheer number of connected users/devices and ubiquitous sensing capabilities. The integrated communication and sensing (ISAC) architectures achieve spectrum sharing between communications and sensing by encompassing just one active radio transmitter and two different receiving chains to accommodate the two functions. On the other hand, a promising technology for implementing low-power and low-cost communication is ambient backscatter communication (ABC), where a tag, often not connected to a battery or a power grid, can deliver a message to a reader by simply reflecting and modulating an incident ambient signal emitted by the radio frequency (RF) emitter of an existing legacy system. This project addresses various design aspects of a new ISAC architecture, called the RadBackCom system, which consists of a legacy radar system, and a backscatter communication system with the carrier signal being the radar clutter echoes. This research will significantly advance the state-of-the-art in the fields of ISAC and ABC. Practical use cases may include the exploitation of ground-based radars for air/road traffic control, environmental/weather monitoring, collision avoidance, intrusion detection, and radio imaging.Specifically, data transmission schemes will be developed when the legacy system is either a pure radar system or a dual functional radar communication (DFRC) system. When there are multiple tags transmitting data, transceiver schemes for both pilot-based sourced systems and pilot-free unsourced systems will be developed. Further, when the legacy system is assisted by a reflecting intelligent surface (RIS), several scenarios will be considered where the RIS also plays the role of an information-bearing tag, a one-bit reader, and a helper, respectively, in the RadBackCom system, and the corresponding solutions will be developed. The proposed approaches exploit an array of advanced techniques including compressed sensing, low-rank processing, simulation-based optimization, algebraic coding theory, iterative decoding, and deep neural networks, and will bring significant innovations to the theory and applications of both ISAC and ABC. Both a realistic simulator and a USRP software-defined radio testbed will be developed to validate the proposed algorithms.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.