[Paper Review] Symbiotic Sensing and Communications Towards 6G: Vision, Applications, and Technology Trends

Zhiqin Wang, Kaifeng Han+6 more|arXiv (Cornell University)|Jun 29, 2021

Advanced Wireless Communication Technologies4 citations

TL;DR

This paper introduces Symbiotic Sensing and Communications (SSaC) as a unifying framework for integrating wireless communication and sensing in 6G networks, enabling simultaneous 'seeing' and 'talking' to the physical world. It proposes a three-stage evolution roadmap—neutralism, commensalism, and mutualism—and outlines key applications, performance metrics, and enabling technologies such as joint waveform design, intelligent reflecting surfaces, and THz sensing.

ABSTRACT

Driven by the vision of intelligent connection of everything and digital twin towards 6G, a myriad of new applications, such as immersive extended reality, autonomous driving, holographic communications, intelligent industrial internet, will emerge in the near future, holding the promise to revolutionize the way we live and work. These trends inspire a novel technical design principle that seamlessly integrates two originally decoupled functionalities, i.e., wireless communication and sensing, into one system in a symbiotic way, which is dubbed symbiotic sensing and communications (SSaC), to endow the wireless network with the capability to "see" and "talk" to the physical world simultaneously. Noting that the term SSaC is used instead of ISAC (integrated sensing and communications) because the word ``symbiotic/symbiosis" is more inclusive and can better accommodate different integration levels and evolution stages of sensing and communications. Aligned with this understanding, this article makes the first attempts to clarify the concept of SSaC, illustrate its vision, envision the three-stage evolution roadmap, namely neutralism, commensalism, and mutualism of SaC. Then, three categories of applications of SSaC are introduced, followed by detailed description of typical use cases in each category. Finally, we summarize the major performance metrics and key enabling technologies for SSaC.

Motivation & Objective

• To establish a unified conceptual framework for symbiotic sensing and communications (SSaC) as a core 6G technology.
• To clarify the distinction between SSaC and prior terms like ISAC or JRC, emphasizing the inclusivity of 'symbiosis' for varying integration levels.
• To propose a three-stage evolution roadmap—neutralism, commensalism, and mutualism—for SSaC development.
• To identify and categorize key application scenarios of SSaC, including immersive XR, autonomous systems, and environmental reconstruction.
• To summarize critical performance metrics and enabling technologies for practical SSaC system design.

Proposed method

• Proposes a new paradigm—SSaC—where communication and sensing are co-designed to achieve mutual benefits, using electromagnetic wave signals (especially RF) for sensing.
• Introduces a three-phase evolution model: neutralism (independent but co-located), commensalism (one benefits from the other), and mutualism (fully integrated, co-designed systems).
• Classifies SSaC applications into three categories: immersive communication, status recognition, and environmental reconstruction.
• Identifies key enabling technologies: joint waveform design (e.g., CD-OFDM, OTFS), networking design for large-scale device support, and advanced signal processing.
• Highlights the role of intelligent reflecting surfaces (IRS) and terahertz (THz) techniques in enhancing sensing resolution and controllability of radio environments.
• Emphasizes the use of model-driven and data-driven approaches for status recognition, with trade-offs in complexity and data requirements.

Experimental results

Research questions

• RQ1 How can sensing and communication be meaningfully integrated in a way that supports mutual benefits across different levels of integration?
• RQ2 What are the distinct evolutionary stages of symbiotic sensing and communications, and how do they differ in functionality and design principles?
• RQ3 What are the key application scenarios for SSaC in 6G, and what are the representative use cases in each category?
• RQ4 What performance metrics are most relevant for evaluating SSaC systems, and how do they differ from traditional communication or radar systems?
• RQ5 Which enabling technologies—such as waveform design, IRS, or THz—most effectively support the realization of SSaC in real-world deployments?

Key findings

• SSaC is proposed as a more inclusive and evolutionarily aware alternative to terms like ISAC or JRC, accommodating varying levels of integration from co-location to full co-design.
• The three-stage evolution roadmap—neutralism, commensalism, and mutualism—provides a structured vision for the development of SSaC systems over time.
• Immersive applications like extended reality (XR) and holographic communications benefit from SSaC by enabling real-time environmental feedback and spatial awareness.
• Status recognition applications, such as gesture recognition and motion detection, are supported by both model-driven and data-driven approaches, with trade-offs in accuracy and training overhead.
• Environmental reconstruction applications leverage intelligent reflecting surfaces (IRS) and terahertz (THz) techniques to achieve high-resolution, controllable sensing for indoor and outdoor scenarios.
• Joint waveform design using OFDM, CD-OFDM, and OTFS waveforms enables efficient spectrum utilization and robust performance in high-mobility environments like vehicular networks.