A Prospective Look: Key Enabling Technologies, Applications and Open Research Topics in 6G Networks (2004.06049v2)

Abstract: The fifth generation (5G) mobile networks are envisaged to enable a plethora of breakthrough advancements in wireless technologies, providing support of a diverse set of services over a single platform. While the deployment of 5G systems is scaling up globally, it is time to look ahead for beyond 5G systems. This is driven by the emerging societal trends, calling for fully automated systems and intelligent services supported by extended reality and haptics communications. To accommodate the stringent requirements of their prospective applications, which are data-driven and defined by extremely low-latency, ultra-reliable, fast and seamless wireless connectivity, research initiatives are currently focusing on a progressive roadmap towards the sixth generation (6G) networks. In this article, we shed light on some of the major enabling technologies for 6G, which are expected to revolutionize the fundamental architectures of cellular networks and provide multiple homogeneous artificial intelligence-empowered services, including distributed communications, control, computing, sensing, and energy, from its core to its end nodes. Particularly, this paper aims to answer several 6G framework related questions: What are the driving forces for the development of 6G? How will the enabling technologies of 6G differ from those in 5G? What kind of applications and interactions will they support which would not be supported by 5G? We address these questions by presenting a profound study of the 6G vision and outlining five of its disruptive technologies, i.e., terahertz communications, programmable metasurfaces, drone-based communications, backscatter communications and tactile internet, as well as their potential applications. Then, by leveraging the state-of-the-art literature surveyed for each technology, we discuss their requirements, key challenges, and open research problems.

• The paper details enabling technologies for 6G networks, including mmWave, THz, and optical wireless communications, highlighting design and interference challenges.
• It emphasizes the application potential of these innovations in achieving ultra-low latency, high data rates, and autonomous services for smart cities and telemedicine.
• The research identifies open challenges in mobility management, secure channel design, and energy-efficient protocols, setting a roadmap for future wireless advancements.

Key Enabling Technologies, Applications, and Research Challenges in 6G Networks

The paper provides a comprehensive overview of the anticipated transformation from fifth generation (5G) to sixth generation (6G) mobile networks, highlighting the projected shift in network requirements driven by emerging societal trends. Specifically, the transition to 6G is motivated by the need for fully automated systems and intelligent services, supporting applications characterized by extremely low latency, ultra-reliability, and high data rates.

Enabling Technologies

The authors delineate several enabling technologies that are expected to underpin the 6G networks. These include:

• Millimeter Wave (mmWave) Communications: Leveraging the higher frequency spectrum to provide increased bandwidth and reduced interference through narrow-beam transmissions. The deployment presents challenges associated with mobility management, interference control, and overcoming blockage effects.
• Terahertz (THz) Communications: Extending the communication spectrum into the THz band to cater to bandwidth-intensive applications. The paper discusses key challenges in transceiver design and channel modeling to counter severe path losses and atmospheric attenuations typical to THz frequencies.
• Optical Wireless Communications (OWC): Comprising visible light communications (VLC), light fidelity (LiFi), and free-space optics (FSO), these technologies promise high data rates and low interference, suitable for specific environments like healthcare and smart transportation systems.
• Programmable Metasurfaces: Offering dynamic control over electromagnetic waves, these surfaces can enhance wireless communication resilience by enabling functions like adaptive beam steering and absorption. The paper highlights the need for advanced dynamic metasurface design and efficient control mechanisms.
• Drone-Based Networking: Enabling flexible communication through agile deployment, drone-based networks can serve as cellular-extension nodes or facilitate innovative applications such as search and rescue operations. Key issues identified include energy efficiency, collision avoidance, and channel characterization.
• Backscatter Communications and Energy Harvesting: Addressing power constraints in massive IoT deployments, backscatter communications enable ultra-low power data transmission, while energy harvesting mechanisms provide sustainable power solutions. The paper points to challenges in interference management and secure communication in such networks.
• Tactile Internet: Enabling real-time latency-sensitive applications through haptic communications, the tactile internet encompasses use cases such as tele-surgery and virtual reality. An essential focus is meeting stringent latency and reliability standards.

Research Implications

The paper systematically identifies open research challenges associated with each enabling technology. For instance, mmWave technology requires new approaches to mitigate challenges posed by mobility and interference. THz communications need advanced hardware design tailored to new spectral environments, while OWC systems require refined physical layer security mechanisms. Furthermore, drone-based networks will need innovations in secure architectures and efficient energy usage.

Future Prospects

The evolution to 6G networks is postulated to support a broader spectrum of Internet-of-Everything (IoE) applications, necessitating novel communication paradigms that integrate computing, sensing, and communications seamlessly. This evolution will demand a convergence of various fields, ensuring that emerging technologies align with the heterogeneous requirements of new applications such as autonomous systems, telemedicine, and smart cities. The paper serves as a roadmap for researchers, elucidating potential directions and underscoring the necessity of interdisciplinary collaboration to address imminent technical hurdles. The implications for future AI development are also profound, with AI anticipated to play a pivotal role in optimizing 6G architectures and resource management strategies.

In summary, the document provides a rich exploration of prospective 6G networks, offering insights into the potential technologies, outlining imminent applications, and speculating on critical research trajectories. It emphasizes the transformative impact 6G networks could have, setting the foundation for future innovations in wireless communications.