A Survey of Symbiotic Radio: Methodologies, Applications, and Future Directions

Abstract

The sixth generation (6G) wireless technology aims to achieve global connectivity with environmentally sustainable networks to improve the overall quality of life. The driving force behind these networks is the rapid evolution of the Internet of Things (IoT), which has led to a proliferation of wireless applications across various domains through the massive deployment of IoT devices. The major challenge is to support these devices with limited radio spectrum and energy-efficient communication. Symbiotic radio (SRad) technology is a promising solution that enables cooperative resource-sharing among radio systems through symbiotic relationships. By fostering mutualistic and competitive resource sharing, SRad technology enables the achievement of both common and individual objectives among the different systems. It is a cutting-edge approach that allows for the creation of new paradigms and efficient resource sharing and management. In this article, we present a detailed survey of SRad with the goal of offering valuable insights for future research and applications. To achieve this, we delve into the fundamental concepts of SRad technology, including radio symbiosis and its symbiotic relationships for coexistence and resource sharing among radio systems. We then review the state-of-the-art methodologies in-depth and introduce potential applications. Finally, we identify and discuss the open challenges and future research directions in this field.

Modulation Design and Optimization for Multiplicative Multiple Access Channel in Symbiotic Radios

“…For the scenario with |h/g| >> √ 2 + 1, the direct link is relatively strong as compared to the reflecting link, and we have α ⋆ = 0, |β ⋆ | = 1. The received signal can be rewritten as y = hs+gsc+z, where g is defined in (8). In this case, the detection of s is dominated by the strong direct link, and the detection of c shows a negligible impact on that of s. Thus,…”

Dynamic Resource Optimization for Energy-Efficient 6G-IoT Ecosystems

“…This makes the non-convex optimization of dynamic large-scale IoT systems a challenging task. By employing this strategy, 6G-IoT networks can achieve high levels of energy efficiency, reduce their environmental impact, and enable the deployment of sustainable IoT solutions [ 25 ]. Despite the potential benefits of energy efficiency in 6G-IoT networks, there are several challenges, such as network complexity and limited energy resources, that need to be addressed to satisfy realistic implementation and successful deployment in dynamic, large-scale IoT environments.…”

Development in ambient backscatter communications

“…There have been a few review papers on BackCom technologies, such as [17][18][19][20][21][22][23][24][25]. The recent review papers [17,18] have been focused on the BackCom RF electronics designs and system prototypes, while the BackCom fundamentals were comprehensively covered in [19][20][21].…”

“…The recent review papers [17,18] have been focused on the BackCom RF electronics designs and system prototypes, while the BackCom fundamentals were comprehensively covered in [19][20][21]. The above review works have been biased more on dedicated BackCom with the ambient BackCom discussed more in [22][23][24][25]. The review [22] discussed the coexistence and spectrum sharing between ambient BackCom systems and other legacy active wireless networks, including traditional active Radar.…”

“…The above review works have been biased more on dedicated BackCom with the ambient BackCom discussed more in [22][23][24][25]. The review [22] discussed the coexistence and spectrum sharing between ambient BackCom systems and other legacy active wireless networks, including traditional active Radar. Another comprehensive overview on bistatic and ambient BackCom was presented in [23], which focused more on hardware architecture, prototypes, backscatter tag authentication and transmission security, as well as the interplay and integration with other IoT networks.…”