From Efficiency to Sustainability: Exploring the Potential of 6G for a Greener Future

Abstract

This article provides a comprehensive examination of sustainable 6G wireless communication systems, addressing the urgent need for environmentally friendly and energy-efficient networks. The background establishes the broader context and significance of the study, emphasizing the escalating concerns surrounding the environmental impact and energy consumption of wireless communication systems. The purpose of this study is to explore and propose sustainable solutions for 6G networks. The methods employed in this research encompass an analysis of various strategies and technologies, including energy-aware network design, dynamic power management, energy harvesting, and green infrastructure deployment. The main findings of this article highlight the effectiveness of these approaches in enhancing energy efficiency, reducing carbon footprint, and optimizing resource management in 6G networks. The conclusions drawn from this study emphasize the importance of sustainable 6G wireless communication systems in achieving a more eco-friendly and energy-efficient future. It is crucial to adopt these sustainable practices to minimize environmental impact and address the increasing energy demands of wireless communication networks. The article provides valuable insights to researchers, industry practitioners, and policymakers, aiding in the development and implementation of sustainable practices for 6G wireless communication systems.

1. Introduction

Wireless technology revolutionizes communication by enabling the transfer of data, signals, and information without physical cables or wires. It encompasses wireless communication between devices, utilizing radio frequency waves to create wireless networks that facilitate voice calls, text messaging, data transfer, and other forms of communication. Wireless technology has had a profound impact on personal and professional spheres [1], providing mobility and convenience, and has evolved through various generations, such as 2G, 3G, 4G, 5G, and the ongoing development of 6G, to deliver faster speeds, increased capacity, and advanced capabilities.

Table 1. Evolution of wireless technologies.

Generation	Year Introduced	Data Speed	Network Capacity	Latency
1G	1980s	Analog	Low	High
2G	1990s	Up to 384 Kbps	Moderate	High
3G	Early 2000s	Up to 2 Mbps	High	Moderate
4G	Late 2000s	Up to 1 Gbps	High	Low
5G	2010s	Up to 10 Gbps	Very High	Low
6G	Expected 2030s	Up to 100 Gbps	Extremely High	Ultra-Low

shows the evolution of wireless technologies over the years.

The 3rd Generation Partnership Project (3GPP) is a global collaboration and standardization organization [2] responsible for developing and maintaining technical specifications for mobile communication systems. Established in 1998, 3GPP brings together various telecommunications standards organizations from around the world, including regional standards bodies and industry associations. Its primary focus is on the development of specifications for mobile network technologies, including GSM, UMTS (3G), LTE (4G), and now, 5G and beyond. 3GPP works on defining the core network architecture [3], radio access technologies, protocols, interfaces, and interoperability standards that enable seamless communication and global compatibility across different networks and devices. These standards play a crucial role in ensuring interoperability between equipment and network components from various vendors, fostering competition, innovation, and a vibrant ecosystem of mobile services and applications. 3GPP continues to evolve and adapt its specifications to meet the requirements of emerging technologies, industry trends, and the evolving needs of mobile communications worldwide.

1.1. Evolution of 5G

The transition from 4G to 5G represents a major advancement in mobile communication technology [4], with profound implications for individuals, businesses, and industries. The need for 5G arose from the exponential growth of mobile data usage, driven by the proliferation of smartphones, IoT devices, and data-intensive applications. As 4G networks reached their limits in terms of capacity and speed, 5G emerged as the solution to meet the increasing demands of a hyper-connected world. The development of 5G involved extensive research, collaboration, and standardization efforts by international organizations like the 3GPP. Technical specifications were defined to achieve key objectives, including faster data rates, ultra-low latency, massive device connectivity, and network flexibility. These specifications paved the way for the introduction of advanced technologies, such as millimeter waves and massive MIMO, which significantly enhanced data transfer speeds, network capacity, and coverage. Beyond technical advancements, 5G introduced a new network architecture that embraced cloud-based infrastructure [5], software-defined networking principles, and virtualization. This shift allowed for more efficient resource utilization, dynamic network management, and the ability to create tailored network slices to meet the specific requirements of different applications and industries. The flexibility and customization capabilities of 5G are poised to unleash a wave of innovation across sectors like healthcare, transportation, manufacturing, entertainment, and more. Commercial deployments of 5G networks began in various regions [6], enabling users to experience enhanced mobile broadband with seamless streaming of high-definition videos, immersive virtual reality, and augmented reality experiences. Additionally, the massive machine-type communication capabilities of 5G are enabling the massive deployment of IoT devices [7], creating opportunities for smart homes, smart cities, and connected industries. The potential of 5G remains vast. It promises to enable breakthrough applications such as autonomous vehicles, remote robotic surgeries, smart energy grids, and immersive telepresence. As 5G networks continue to evolve and expand, unlocking their full potential will require ongoing infrastructure investments, device proliferation, and innovative partnerships across the telecommunications ecosystem. This transition from 4G to 5G represents a transformative shift in mobile communication, bringing faster speeds, lower latency, increased capacity, and unprecedented connectivity. It sets the stage for a new era of technological advancements, business opportunities, and societal transformation.

1.2. Beyond 5G (B5G) and Evolution of 6G

5G and B5G are both wireless communication technologies with distinct focuses. 5G is the fifth-generation wireless technology that offers faster speeds, lower latency, and high device capacity, enabling transformative applications and services. It requires significant infrastructure upgrades and primarily targets urban areas. On the other hand, B5G, or beyond 5G [8], aims to enhance and extend the capabilities of 5G networks. It focuses on improving coverage in rural areas, enhancing energy efficiency, optimizing spectrum utilization, and integrating advanced security features. B5G acts as a bridge between 5G and future 6G deployments, addressing emerging requirements and setting the stage for further advancements in wireless communication. While 5G is already deployed and widely adopted, B5G is still a concept under development, aiming to augment and refine the capabilities of existing networks.

Table 2. Performance improvement from 5G to 6G.

Technology	Speed	Latency	Capacity
5G	10 Gbps	Low (sub-millisecond)	High (massive IoT)
B5G	Improved	Reduced	Enhanced
6G	100 Gbps	Ultra-low	Massive (billions)

highlights the differences between 5G, B5G, and 6G.

6G, the sixth-generation wireless technology [9,10], is the next frontier in mobile communication systems expected to emerge in the 2030s. Building upon the advancements of its predecessor, 5G, 6G aims to revolutionize wireless connectivity by delivering unprecedented speeds, ultra-low latency, and massive device connectivity. With projected data rates of up to 100 Gbps, 6G is anticipated to provide an immersive and seamless user experience [11], enabling transformative applications such as holographic communication, augmented reality (AR), virtual reality (VR), and advanced IoT solutions. The development of 6G is driven by the need to address the ever-growing demands of the digital era. It aims to overcome the limitations of previous generations and unlock new possibilities for communication, collaboration, and technological innovation. 6G envisions a hyper-connected world where connectivity is ubiquitous, empowering various sectors, including healthcare, transportation, smart cities, entertainment, and industrial automation. This technology is expected to be a catalyst for breakthroughs in areas such as artificial intelligence (AI), machine learning (ML), edge computing [12], and network automation, enabling intelligent and autonomous systems to operate seamlessly.

While 6G is still in the early stages of research and standardization, experts envision a future where it will serve as a key enabler for cutting-edge technologies, reshaping industries and transforming the way we live, work, and interact. The development of 6G is a collaborative effort involving academia [13], industry, and standardization bodies to define the fundamental principles, technologies, and architectures that will underpin this next-generation wireless ecosystem.

The evolution toward 6G is expected to be a significant leap forward in wireless technology [14], building upon the foundations established by previous generations. While 5G has already transformed mobile communication with its high speeds and low latency, 6G aims to push the boundaries even further. The development of 6G [15,16,17] involves exploring advanced technologies and concepts such as terahertz frequencies, massive MIMO (multiple-input multiple-output) systems, intelligent beamforming, and integrated satellite and terrestrial networks. One of the key focuses in the evolution of 6G is the concept of hyper-connectivity, where not only people but also devices and objects become seamlessly interconnected. This vision involves integrating various communication domains [9], including wireless, optical, and satellite networks, to create a truly ubiquitous and global network infrastructure. Furthermore, 6G aims to support advanced applications such as holographic communication, advanced AR/VR experiences, tactile internet, and AI-driven autonomous systems. Additionally, sustainability and energy efficiency are crucial considerations in the evolution of 6G [18]. Efforts are being made to minimize the environmental impact by optimizing network architectures, reducing power consumption, and developing energy-efficient hardware components. Moreover, 6G envisions the integration of AI and machine learning techniques to enhance network intelligence [19], optimize resource allocation, and enable autonomous decision-making. While the full realization of 6G is still several years away, research and development efforts are underway to shape its foundation. Collaborative initiatives, standardization bodies, and academia are actively exploring the technical and societal challenges associated with 6G, aiming to define the requirements, performance targets, and fundamental principles that will shape the next-generation wireless ecosystem. The evolution of 6G holds great promise for transforming industries, enabling new applications, and unlocking unprecedented levels of connectivity and innovation in the digital era.

The vision and requirements of 6G wireless networks encompass a transformative and comprehensive approach to meet the evolving needs of the digital era. While still in the early stages of research and development, several key aspects have been identified to shape the foundation of 6G.

Table 3. Comparative analysis of 5G and 6G key performance indicators.

Type	Key Performance Indicators	5G	6G
System Management	Reliability	10−5 packet error rate	10−9 packet error rate
	Mobility	500 km/h	1000 km/h
System Latency	End-to-end latency	1 ms	0.1 ms
	Delay jitter	N/A	10 ms
System Capacity	Peak data rate	20 Gbps	1 Tbps
	Experienced data rate	0.1 Gbps	1000 Gbps
	Peak spectral eff. *	30 b/s/Hz	60 b/s/Hz
	Experienced spectral eff. *	0.3 b/s/Hz	3 b/s/Hz
	Max channel bandwidth	1 GHz	100 GHz
	Connection density	106 devices/km2	107 devices/km2
Computing Technique	Technique of focus	Fog/edge computing, cloud computing	Quantum computing, Fog/edge computing
	Network type	SDN, NFV, Slicing	Intelligent Cloud, AI-based slicing, ML, DL

* eff. stands for efficiency.

contrasts the key performance indicators of 5G and 6G.

The vision of 6G revolves around hyper-connectivity [20], where people, devices, and objects are seamlessly interconnected, enabling a truly ubiquitous and immersive communication experience. The network aims to support massive device connectivity, providing a reliable and high-speed connection for billions of devices simultaneously. This vision extends beyond traditional communication domains, integrating wireless, optical, and satellite networks to create a global and unified infrastructure. The goal is to provide uninterrupted connectivity and seamless handoff between different networks, ensuring ubiquitous coverage even in remote areas. In terms of performance, 6G envisions ultra-high data rates [21], with projected speeds of up to 100 Gbps. This dramatic increase in bandwidth will enable a range of transformative applications, such as holographic communication, advanced augmented reality (AR) and virtual reality (VR), and immersive gaming experiences. Ultra-low latency is another crucial requirement for 6G networks, aiming to reduce delay to the sub-millisecond level. This low-latency capability is essential for real-time applications such as autonomous vehicles, remote surgery, and tactile internet, where instantaneous responsiveness is critical. Sustainability and energy efficiency are key considerations for 6G networks. Additionally, the integration of artificial intelligence (AI) and machine learning (ML) techniques plays a significant role in 6G. These technologies will enable intelligent resource allocation, network optimization, and autonomous decision-making, ensuring efficient and adaptive network operations. Ethical considerations, inclusivity, and social impact [22] are also emphasized to ensure that 6G networks benefit all individuals and communities, bridging the digital divide and enabling equal access to opportunities. Overall, the vision and requirements of 6G wireless networks aim to create a transformative and inclusive wireless ecosystem. With ultra-high speeds, ultra-low latency, massive connectivity, sustainability, and intelligence, 6G envisions a future where advanced applications and services seamlessly integrate into our daily lives, revolutionizing industries, empowering emerging technologies, and reshaping the way we communicate, collaborate, and experience the digital world.

1.3. Contributions and Paper Structure

This paper offers significant contributions to the discourse on 6G wireless communication systems, providing a comprehensive analysis of their potential and impact. In particular, we stress the importance of sustainability over efficiency. The main contributions are listed below:

• This paper discusses sustainable materials and construction methods for 6G infrastructure, which involve the use of recycled or environmentally friendly components in base stations and equipment. This not only reduces the carbon footprint associated with network deployment but also provides valuable technical insights, particularly in the “Materials and Methods” section. Here, the quintuple helix model, 6G architecture, and the integration of mMTC and URLLC are elucidated. This technical roadmap effectively bridges the gap between theory and practical implementation with a strong emphasis on sustainability. It serves as a valuable guide for researchers and practitioners involved in designing and deploying 6G networks.
• Section 4.1 of this paper highlights how sustainable 6G policies prioritize digital inclusion and ensure equal access to technology for all, bridging the digital divide. It explores initiatives that extend connectivity to underserved and remote areas, contributing to social and environmental sustainability.
• In Section 3, this paper delves into the realm of 6G technology, where eco-conscious decisions reign supreme. This section navigates through the art of selecting environmentally friendly materials for 6G devices and infrastructure. The spotlight is on cutting-edge sustainable manufacturing techniques, including the use of recycled materials and methods that minimize environmental impact. However, the journey does not stop there. Section 3.3 reveals a strategic approach to waste management, ensuring that even after the curtain falls on 6G creations, the show goes on with minimal environmental impact.
• This paper presents innovative signal processing techniques tailored for 6G communication systems. This contribution involves new methods for efficient beamforming, interference mitigation, and adaptive modulation schemes to enhance data rates and reliability in 6G networks.
• This paper is meticulously crafted to provide a comprehensive and self-contained understanding of the subject matter. Its highly descriptive nature ensures that readers can grasp the intricacies of the topic without referring to multiple sources. By presenting a holistic view of the subject matter, this paper aims to streamline the reader’s journey, offering a comprehensive resource that stands on its own for a thorough comprehension of the discussed concepts.

The structure of this paper is illustrated in Figure 1, starting with an “Introduction” that traces the evolution from 5G to 6G. The remaining core sections are as follows:

• Connection Between Mobile Communications and Sustainability: This section explores the relationship between mobile communications and sustainability, emphasizing how 6G can contribute to achieving the United Nations Sustainable Development Goals (SDGs). It delves into societal impacts beyond technical aspects.
• Key Drivers of 6G Wireless Communication System: Investigating the fundamental forces propelling 6G’s development, including energy efficiency, sustainable infrastructure, circular economy principles, and AI/ML integration. It provides insights for informed decision-making and investments.
• 6G Applications: Discussing transformative 6G use cases, such as holographic communication, autonomous driving, IoBNT, Industry 4.0, XR, and wireless brain-computer interaction. The focus here is on practical implications.
• Materials and Methods: This technical section elaborates on the quintuple helix model, 6G architecture, and the integration of mMTC and URLLC. It bridges theory and practice, guiding researchers and practitioners in designing 6G networks.
• Future Research Challenges and Opportunities: Identifying challenges and opportunities in the 6G landscape, this section calls for collaboration among researchers, policymakers, and industry leaders to address evolving technology trends.

In summary, this paper offers a comprehensive exploration of 6G wireless communication systems, covering conceptual frameworks, technical insights, potential applications, and future challenges. It provides valuable guidance for impactful research and innovation in the 6G field.

2. Connection between Mobile Communications and Sustainability

The emergence of Industry Revolution 4.0 has sparked a rediscovery of network telecommunications [23], prompting a renewed focus on sustainability as the standard framework for validating concepts, practical applications, and discoveries in today’s rapidly evolving world. At the forefront of this paradigm shift is the 2030 Agenda for Sustainable Development outlined by the United Nations. A thorough analysis of the interaction between mobile communication networks and sustainability is provided in [24], highlighting the profound impact of these networks on the achievement of the UN Sustainable Development Goals (SDGs). The introduction of 5G networks has revolutionized the modern world, offering a wide range of capabilities and features to address the exponential growth of connected devices in various domains. However, the scope of intervention in the realm of mobile telecommunications extends beyond 5G, encompassing advanced network technologies such as B5G and 6G. The 6G system, building upon the foundations of 5G, presents a transformative architecture capable of supporting various use cases. These include innovative features like air interface enhancements, novel spectrum allocation for 6G, integration of artificial intelligence and machine learning in networks [25], advanced beamforming utilizing VLSA (Very Large-Scale Antenna) technology, and seamless coexistence of multiple radio technologies.

2.1. Sustainable Development and Information and Communication Technology

As per the seminal work of Goodland and Daly, sustainability can be classified into three overarching dimensions: environmental, social, and economic sustainability. To conduct and implement a common framework for sustainable mobile communication, it is crucial to consider fundamental factors that significantly influence the design. These factors are outlined below:

• Energy Efficiency: Energy efficiency stands as a paramount aspect of sustainable mobile communication [26], as it directly impacts both the economic and ecological aspects of cellular networks. With the increasing number of base stations in these networks, which account for 57% of total energy consumption, there is a subsequent rise in operational expenditure (OPEX) due to higher electricity bills. To enhance energy efficiency, optimizing base station energy consumption through efficient hardware design and power management techniques becomes essential. Implementing energy-saving features like sleep modes, dynamic power scaling, and advanced power amplifiers [27,28], as well as incorporating renewable energy sources and promoting energy-efficient practices in network infrastructure, is a crucial consideration.
• Network Infrastructure: Scalable wireless communication needs a lot of coordination work across many distributed systems, along with expensive infrastructure upkeep. While the coverage gaps of fixed infrastructure are diminishing, there are still areas, such as underground environments, rural regions, and disaster-stricken areas, where existing wireless networks remain unavailable. In such cases, exploring innovative approaches for the rapid deployment of wireless infrastructure becomes crucial. Designing a network infrastructure for sustainable mobile communication necessitates consideration of factors like coverage [29], capacity, reliability, and scalability. It should ensure reliable and high-quality connectivity to users while accommodating increasing demand and traffic. Scalability and adaptability to changing needs and evolving technologies are also key aspects. Additionally, minimizing the environmental impact through energy-efficient design becomes imperative.
• Network Coverage: Network coverage plays a vital role in mobile communication [30], directly influencing the availability and quality of wireless connectivity in specific regions. Insufficient network coverage hampers the ability of mobile devices to access online services, make voice calls, and send messages. In the context of 5G, network coverage gains heightened importance as it directly impacts the efficacy of the technology, facilitating the realization of transformative applications such as autonomous vehicles, smart cities, and industrial automation.
• Privacy and Data Security: Privacy and data security hold critical significance in mobile communications due to the inherent vulnerabilities of mobile devices and networks. These vulnerabilities expose them to various security threats, including eavesdropping, tampering, and unauthorized access. Mobile devices store a wealth of sensitive personal information, making them attractive targets for exploitation by malicious actors. Additionally, mobile networks transmit substantial volumes of data, including voice and multimedia content [31], which can be intercepted and manipulated by unauthorized parties. Thus, safeguarding the privacy and security of mobile communications becomes paramount to protecting users’ personal information and preventing unauthorized access to sensitive data. These concerns span across 2G, 3G, 4G, and 5G networks, each presenting distinct security and privacy challenges that require diligent attention and resolution.

2.2. Grounds for Achieving the UN SDGs and Their Implications

The information mentioned above discusses the factors that affect the relationship and dependency between sustainability and ICT. The next dependency to look after is the impact of new and present mobile telecommunication [32,33] over the UN SDGs (United Nations Sustainable Development Goals). Figure 2 illustrates the goals of SDG.

Table 4. The impact of mobile telecommunications over UN SDGs.

UN SDGs	Dependency of the SDGs and Mobile Communication
	Mobile communications stimulate local economic growth. Reduced access to financial resources through microfinance and mobile money. Create work options for those who are incredibly poor [34]. Frequent toileting.
	Farmers can increase crop yields and company productivity with the aid of ICT. Improved access to programs for training, weather predictions, and financial data [35].
	Healthcare providers are able to be reached via mobile communications. Improve water quality through IoT. Access to digital medical records and remote patient monitoring [36].
	ICT is driving a revolution in online education. Anytime, anyplace access to educational content has been made possible by mobile devices. Mobile devices are used by teachers for interactive training and tutoring.
	Mobile phones help women feel safer and connected. Connecting women to female-specific activities and fostering collaborative economic growth. Access to resources, opportunities, and services.
	ICT enables smart water management and monitoring. Facilitates equitable extension of water and sanitation services.
	Mobile communications aid in determining renewable energy viability. Online resources for clean energy procurement and smart grid solutions.
	Mobile communications increase market size and provide access to mobile financial services. ICT skills create new employment opportunities.
	Mobile networks provide affordable access to voice and data services. IoT solutions for sustainable manufacturing and smart metering.
	Mobile communications enable access to information and social networks. Facilitate mobile money and digital identity services.
	Advanced communications techniques improve teleworking and collaborative innovation. Self-driving cars and drones enhance public transport and productivity.
	ICT enables sustainable production and consumption. Reduces energy consumption and negative impacts of ICT.
	Mobile communication facilitates smart traffic management and smart grids. Helps reduce greenhouse gas emissions in various sectors.
	ICT aids in the conservation and sustainable use of oceans. Monitors biodiversity, pollution, and ecosystem evolution.
	ICT supports conservation and sustainable use of terrestrial ecosystems. Monitors biodiversity, pollution, and weather patterns.
	Mobile technology helps prevent violence and ensures data privacy and security. ICT enhances transparency, empowers citizens, and aids in disasters.
	The intent of collaborations is displayed via the various MoUs between public and private sectors. Sustainable development pillars are accelerated by ICT and effective implementation.

discusses each goal and how it is affected by mobile telecommunications.

While Table 4 demonstrates the influence of mobile communication on sustainability and its potential to partially or wholly contribute to the UN SDGs, it is very cardinal to keep in mind that making sure of only these points cannot constitute the complete solution to the complicated challenges of sustainability. The interconnected nature of the Goals and targets underscores the need to recognize the inherent complexity involved in decision-making, often resulting in trade-offs that may lead to winners and losers. Realizing a transformative agenda, characterized by a deliberate departure from the status quo, requires meticulous consideration of the intricate interplay between goals and targets. The Global Sustainable Development Report underscores the imperative of a nuanced examination of the intricate interactions and potential trade-offs among diverse Sustainable Development Goals (SDGs) and targets. It emphasizes the need to adopt a holistic approach that safeguards against progress in one domain undermining advancements in another. To navigate this complex landscape effectively, the report is discussed in [10], which identifies and elucidates several key cross-cutting themes (also called “entry points”) essential for sustainable development:

• Incorporated tactics: Adopt innovative, holistic approaches considering interactions and synergies between goals and policies.
• Policy coherence: Prioritize coherence, breaking silos, aligning rules, and collaborating across sectors for interconnected goal achievement.
• Transformative learning: Embrace experimentation and openness, fostering innovation to adapt and seize new opportunities.
• State capacity: Strengthen institutional capabilities, resources, and expertise for effective implementation and monitoring.
• Competent institutions: Foster transparent, inclusive institutions, enabling equitable participation and efficient resource allocation.
• Constructive synergies: Leverage synergies for optimized resource allocation and accelerated progress while mitigating negative trade-offs.

3. Key Drivers of 6G Wireless Communication System

Wireless communication systems have undergone remarkable advancements, and as the future unfolds, the next generation, known as 6G, is poised to bring about transformative changes. 6G promises unparalleled speed, ultra-low latency, and massive device connectivity, opening up new possibilities for artificial intelligence, virtual reality, and the Internet of Things. However, amidst this drive for technological progress, the industry recognizes the importance of emphasizing sustainability as a key driver in the development and implementation of 6G wireless communication systems [37]. Sustainability serves as a guiding principle to ensure that advancements are not achieved at the expense of environmental degradation or social inequality. The key drivers of sustainability in 6G wireless communication systems encompass various dimensions. Energy efficiency stands at the forefront, addressing the increasing demand for data and the associated energy consumption. Minimizing power usage through advanced techniques and intelligent network optimization algorithms is paramount.

As shown in Figure 3, the six pillars of 6G wireless communication systems encompass crucial aspects of its design and capabilities. They include

• Velocity maximization: Focusing on achieving unprecedented speeds for data transmission;
• Ultra-low temporal lag: Aiming for minimal time delays and ultra-low latency.
• Hyperconnectivity: Enabling seamless connectivity for a vast number of devices.
• Cognitive autonomy: Integrating artificial intelligence and machine learning for intelligent decision-making,
• Eco-optimization: Emphasizing energy efficiency and minimizing environmental impact, and
• Advanced materialization: Leveraging cutting-edge materials and technologies for enhanced performance.

These pillars collectively shape the future of wireless communication, enabling faster speeds, lower latency, massive connectivity, intelligent networks, sustainable practices, and technological advancements in 6G systems. The key drivers for the next-gen 6G revolution lie in four factors, which will be discussed in detail in this section.

3.1. Energy Efficiency and Power Optimization

Energy efficiency and power optimization are crucial focal points in the development of 6G wireless communication systems [38], aimed at fostering sustainability and environmentally conscious practices. As the demand for data transmission escalates and the number of connected devices proliferates, it becomes imperative to curtail energy consumption while upholding superior network performance. This section delves into a comprehensive exploration of strategies and technologies that can be employed to achieve exemplary energy efficiency and power optimization within the realm of 6G. The pursuit of energy efficiency encompasses a broad spectrum of considerations, encompassing advanced power management techniques, dynamic energy harvesting, and energy-aware network design and protocols. By implementing sophisticated power management techniques, such as intelligent power allocation, adaptive power control, and energy-saving algorithms [39], network components and devices can efficiently harness power resources, thereby mitigating unnecessary energy dissipation.

3.1.1. Advanced Power Management Techniques

Advanced power management techniques are vital for optimizing energy consumption and ensuring efficient power utilization in 6G wireless communication systems. These techniques, employing sophisticated algorithms and adaptive strategies for power resource allocation, aim to reduce energy wastage, enhance overall energy efficiency, and extend device battery life. Importantly, they play a pivotal role in fostering sustainability within 6G technology. By minimizing energy consumption and aligning with clean and renewable energy sources, these techniques contribute to reducing the carbon footprint of telecommunications infrastructure [40]. Furthermore, they promote extended device lifespans, minimize electronic waste, and align with United Nations Sustainable Development Goals, particularly those related to clean energy, climate action, and responsible consumption. In doing so, advanced power management techniques not only improve efficiency but also actively engage in environmental stewardship, forging a more responsible and eco-friendly path for the 6G wireless communication landscape.

3.1.2. Dynamic Energy Harvesting and Wireless Charging

Dynamic energy harvesting refers to the process of capturing and harnessing ambient energy from the surrounding environment to power devices and systems. This technique leverages various energy sources, such as solar radiation, kinetic energy [41], thermal gradients, and electromagnetic waves, to convert them into usable electrical energy. Advanced technologies like photovoltaic cells, piezoelectric materials, thermoelectric generators, and RF energy harvesters are employed to capture and convert these energy forms efficiently. Dynamic energy harvesting systems employ sophisticated algorithms and control mechanisms to optimize energy extraction from the environment. By integrating dynamic energy harvesting into 6G wireless communication systems [42], devices can operate autonomously, reducing the dependency on traditional power sources and enabling sustainable and self-sufficient operation.

Wireless charging, encompassing inductive, resonant, and radio frequency (RF) energy transfer methods, revolutionizes the transmission of electrical power within 6G wireless communication systems, eliminating the need for physical connections or cumbersome cables. This not only offers convenience but also aligns with sustainability goals. The heart of this innovation lies in the utilization of electromagnetic fields that bridge the gap between a transmitting charging pad and a receiving device, reducing e-waste associated with traditional cables and connectors. As power is transmitted, the charging pad generates alternating current (AC), thereby creating a magnetic field. This magnetic field induces an alternating voltage in the receiving device, promoting more efficient use of energy and reducing power wastage. Subsequently, this voltage is rectified and harnessed to replenish the device’s battery, contributing to prolonged device lifespans and responsible consumption practices. Within 6G networks, these wireless charging technologies operate efficiently over short to medium distances, reducing energy transmission losses and supporting the use of renewable energy sources. Moreover, they incorporate sophisticated power management techniques, including adaptive power control and dynamic charging profiles, to enhance energy transfer efficiency, lower energy consumption, and ensure compatibility across a diverse range of devices, thereby promoting eco-friendly practices and a more sustainable technological ecosystem. Power management techniques for different generations of mobile communication are summarized in

Table 5. Power management techniques from 1G to 6G [43,44].

Generation	Power Management Techniques	Key Features	Advantages	Challenges
1G	Basic power-saving techniques	Low-power modes	Energy conservation	Limited power optimization capabilities
2G	Sleep mode activation, dynamic power control	Idle mode activation, power adjustment based on demand	Enhanced power efficiency, optimized resource allocation	Limited adaptability to fluctuating network conditions
3G	Advanced power control, adaptive modulation	Dynamic power adjustment, modulation scheme optimization	Improved power management, efficient signal transmission	Limited power optimization for multimedia applications
4G	Dynamic power allocation, enhanced sleep mode optimization	Adaptive resource allocation, intelligent sleep mode optimization	Optimal power utilization, reduced wastage	Limited power management for massive IoT connectivity
5G	Intelligent power management, beamforming technology	Dynamic power control, beamforming for efficient signal transmission	Enhanced energy efficiency, improved coverage	Complex network infrastructure, higher implementation costs
6G	Advanced power allocation, adaptive power control, energy-saving algorithms, intelligent power management	Dynamic power optimization, intelligent resource allocation, energy-efficient algorithms	Optimal power utilization, improved network performance	Advanced implementation requirements, higher complexity

.

Wireless charging in 6G wireless communication systems provides the convenience of charging devices without physical connectors or cables. It enables seamless integration of charging capabilities into various devices and infrastructure, such as smartphones, wearables, Internet of Things (IoT) devices, and charging pads embedded in public spaces. Figure 4 depicts the general working of wireless charging. This technology promotes sustainability by reducing e-waste generated by traditional charging methods and supporting the development of energy-efficient and environmentally friendly wireless devices. In

Table 6. Wireless charging standards.

Wireless Charging Standard	Key Features	Charging Power	Supported Devices	Compatibility
Qi Wireless Charging	Widely adopted, inductive charging	Up to 15 W	Smartphones, wearables, IoT devices	Widely compatible
AirFuel Resonant	Longer distance charging, resonant technology	Up to 50 W	Various device types	Widely compatible
Power Matters Alliance (PMA)	Inductive charging, used in various industries	Up to 5 W	Smartphones, tablets, wearables	Limited compatibility
Wireless Power Consortium	Qi-based standard, interoperability	Up to 15 W	Smartphones, wearables, IoT devices	Widely compatible
Rezence (A4WP)	Resonant technology, multi-device charging	Up to 30 W	Laptops, tablets, wearables	Limited compatibility
USB Power Delivery (USB PD)	Universal standard, fast charging	Up to 100 W	Smartphones, laptops, tablets	Widely compatible
NFC-Based Wireless Charging	Near field communication for wireless charging	Up to 1 W	Smartphones, wearables, IoT devices	Limited compatibility
Cota Wireless Charging	Over-the-air charging, long-range	Up to 2 W	Various device types	Limited compatibility
PowerSpot Wireless Charging	Over-the-air charging, distance charging	Up to 10 W	Smartphones, wearables, IoT devices	Limited compatibility
Resonant Frequency Wireless	Resonant frequency technology, spatial freedom	Up to 20 W	Various device types	Limited compatibility

, each wireless charging standard is listed along with key features, charging power capabilities, supported devices, and compatibility. The “Key Features” column highlights notable characteristics or advantages of each standard, such as adoption rate or specific technology used. The “Charging Power” column specifies the maximum power that can be delivered by the standard. The “Supported Devices” column refers to the types of devices that are commonly compatible with the standard. The “Compatibility” column provides an indication of the overall compatibility of the standard with a range of devices, from widely compatible to limited compatibility.

3.1.3. Energy-Aware Network Design and Protocols

This pillar aims to address the increasing energy demands of 6G networks while ensuring optimal performance and sustainability. In the context of 6G, energy-aware network design [45] encompasses various considerations, such as the layout of network elements, deployment of low-power base stations, and the selection of energy-efficient hardware components. It involves optimizing network topology to minimize energy consumption, improve coverage, and reduce interference. Moreover, energy-aware design involves the strategic placement of relay nodes, intelligent antenna systems, and small-cell deployments to enhance network capacity and energy efficiency. Figure 5 shows the architecture of an energy-aware 6G network.

Energy-aware protocols in 6G networks [46] employ advanced techniques to optimize energy consumption without compromising performance. These protocols leverage dynamic power management mechanisms to dynamically adjust the power usage of network elements based on traffic demands. By intelligently powering down underutilized resources, the network can achieve significant energy savings. Additionally, adaptive modulation and coding techniques optimize the transmission parameters, such as modulation schemes and coding rates, based on channel conditions and traffic requirements. This enables efficient use of resources and minimizes energy expenditure during wireless data transmission. Traffic management in energy-aware 6G networks focuses on intelligent routing and scheduling algorithms that optimize the use of network resources while minimizing energy consumption. Advanced load balancing techniques distribute traffic efficiently across network nodes, avoiding congestion and ensuring optimal resource utilization. Additionally, energy-aware traffic management incorporates data compression and aggregation methods to reduce the amount of transmitted data, thereby lowering energy requirements for wireless communication.

By integrating energy-aware network design and protocols into 6G wireless communication systems, significant improvements in energy efficiency, network capacity, and sustainability can be achieved. These approaches ensure that 6G networks can meet the increasing demands of data-intensive applications while minimizing their environmental impact and maximizing resource utilization.

3.2. Sustainable Infrastructure and Green Networks

This pillar is a fundamental component of 6G, the next generation of wireless communication systems. It places a strong emphasis on creating an environmentally sustainable telecommunications industry that minimizes its carbon footprint and reduces the overall impact on the planet. The expansion of digital connectivity and the ever-increasing demand for data necessitates addressing the environmental challenges associated with the growth of telecommunications infrastructure. The goal of this pillar is to develop and implement sustainable practices and technologies that promote energy efficiency, reduce greenhouse gas emissions, and utilize eco-friendly materials throughout the network infrastructure [47]. The focus on sustainable infrastructure within 6G aims to optimize the use of resources and minimize waste. This includes designing energy-efficient base stations and antennas that consume less power and operate using renewable energy sources whenever possible. The deployment of green base stations and antennas plays a vital role in reducing the energy consumption and environmental impact of wireless networks. In addition, the pillar underscores the importance of energy-efficient data centers and cloud computing solutions. Data centers form the core of modern telecommunications infrastructure, and their energy consumption can be significant. By adopting energy-efficient practices, such as virtualization and efficient cooling systems, data centers can reduce their power requirements and minimize their environmental impact. Furthermore, the use of renewable energy sources for data centers can contribute to a more sustainable and greener network ecosystem.

3.2.1. Green Base Stations and Antennas

In the context of 6G wireless communication, “Green Base Stations and Antennas” refer to the development and implementation of energy-efficient and environmentally friendly infrastructure components. These components play a vital role in reducing energy consumption, minimizing carbon emissions, and promoting sustainability in the telecommunications industry. Traditional base stations and antennas used in wireless networks consume significant amounts of energy, resulting in substantial carbon emissions. With the advent of 6G, there is a growing focus on designing base stations and antennas that are more energy-efficient and utilize renewable energy sources whenever possible [48]. Green base stations are designed to optimize energy consumption without compromising network performance. They incorporate advanced technologies such as dynamic power management, intelligent power amplifiers, and energy-efficient radio frequency (RF) components. These innovations help reduce power consumption during periods of low network traffic and dynamically adjust power levels based on demand, leading to substantial energy savings. Figure 6 illustrates the overall architecture of green base stations.

The integration of green base stations and antennas into 6G wireless communication networks aligns with the industry’s commitment to environmental sustainability. By adopting energy-efficient technologies, optimizing power consumption, and utilizing renewable energy sources, these components contribute to a more sustainable and eco-friendly telecommunications ecosystem

3.2.2. Energy-Efficient Data Centers and Cloud Computing

Energy-efficient data centers and cloud computing are integral components of modern technology infrastructure and will play a crucial role as pillars of 6G networks. As the demand for higher data processing capabilities and increased connectivity continues to rise, there are significant challenges in terms of energy consumption and environmental impact that need to be addressed [49]. Traditional data centers consume substantial amounts of energy due to the requirements of cooling systems, power distribution, and server operation. This not only leads to higher operational costs but also contributes to carbon emissions and environmental degradation. To tackle these challenges, the concept of energy-efficient data centers has emerged. These data centers focus on minimizing energy usage and optimizing resource utilization without compromising performance.

Cloud computing, which relies on data centers, is a key component of 6G networks. It enables centralized storage, processing, and delivery of services and applications to a wide range of devices. As 6G networks will support more devices and enable real-time, data-intensive applications, cloud computing becomes increasingly vital. The advantages of cloud computing in the context of 6G include scalability, edge computing integration, service virtualization, and resource sharing [50]. Cloud computing allows for dynamic allocation of resources based on demand, enabling seamless scalability to accommodate the requirements of a vast number of connected devices. Integrating cloud computing with edge computing enables data processing and storage at the network edge, reducing latency and enhancing performance for time-critical applications. As depicted in Figure 7, the 6G cloud-native system aims to establish a wide-area cloud infrastructure that seamlessly integrates the computing capabilities of mobile devices, mobile networks (including radio access network (RAN) cloud and core network (CN) cloud), and data centers. This unified cloud environment facilitates the efficient sharing of computing resources and enables the provision of comprehensive computing services to user applications.

The system architecture illustrates the integration of computing resources from mobile devices, RAN clouds, CN clouds, and data centers into a distributed cloud that spans a wide geographic area. This departure from existing technologies, where clouds are typically situated in the data network beyond the mobile core network, emphasizes the goal of creating a unified computing cloud that encompasses the diverse functionalities of data centers.

The 6G system is designed to be built upon cloud infrastructure, meticulously optimized to support ubiquitous computing, and inherently capable of delivering a range of computing services, including infrastructure services, platform services, and software services. Subscribers of these cloud computing services can encompass mobile devices, mobile device vendors, application developers, and cloud service providers (CSPs).

3.2.3. Eco-Friendly Materials for Network Components

The concept of “Eco-Friendly Materials for Network Components” focuses on the use of environmentally sustainable and low-impact materials in the design and manufacturing of various network components and infrastructure required for 6G networks. With increasing global concern about the environmental impact of technology and the urgent need to address climate change, industries, including telecommunications, are recognizing the importance of implementing sustainable practices. As 6G networks will require the deployment of a vast number of base stations, antennas, and other network infrastructure components, using eco-friendly materials in their construction can significantly reduce the environmental footprint. This involves considering the use of recycled or recyclable materials, such as sustainable plastics or metals, to minimize waste generation and promote a circular economy. Energy efficiency is another critical aspect of 6G networks. By employing eco-friendly materials in the design and manufacturing of network components, energy consumption during operation can be reduced, thereby contributing to the overall energy efficiency goals of 6G. Lightweight and energy-efficient materials can help achieve this objective, thereby minimizing the carbon footprint. Moreover, emphasizing sustainable manufacturing practices is crucial. This involves reducing waste, optimizing energy usage, and adopting cleaner production techniques during the manufacturing processes of network components. The many aspects of eco-friendly 6G network components are summarized in

Table 7. Eco-friendly network components.

Network Component	Eco-Friendly Materials	Benefits	Examples
Base Stations	Recycled plastics	Reduces waste generation and promotes circular economy	Base station housing made from recycled plastic
	Sustainable metals	Minimizes resource depletion	Antenna supports made from sustainably sourced metals
Antennas	Bio-based plastics	Lower environmental impact over the lifecycle	Antenna casings made from bio-based plastics
	Responsibly sourced materials	Supports sustainable material extraction	Antenna reflectors made from responsibly sourced materials
End-User Devices	Recyclable materials	Enables proper disposal and recycling	Smartphone cases made from recyclable materials
	Energy-efficient components	Reduces power consumption and carbon emissions	Energy-efficient processors and display panels
Network Cables	Sustainable insulation	Minimizes environmental impact during production and disposal	Cables with insulation made from sustainable materials
	Low-emission materials	Reduces carbon footprint	Cables with low-emission materials for reduced environmental impact
Network Infrastructure	Renewable energy sources	Promotes clean and sustainable power generation	Base stations powered by renewable energy sources
	Energy-efficient designs	Reduces overall energy consumption	Network equipment designed for energy efficiency
	Recyclable components	Facilitates proper disposal and recycling	Use of recyclable components in network infrastructure
Manufacturing Processes	Waste reduction measures	Minimizes waste generation and landfill usage	Implementation of lean manufacturing principles
	Energy optimization	Reduces energy consumption during production	Use of energy-efficient equipment and processes
	Cleaner production techniques	Minimizes environmental pollutants	Adoption of environmentally friendly production methods

. By doing so, the eco-friendliness of these components can be enhanced, aligning with the broader goal of creating a more sustainable and environmentally conscious telecommunications industry.

3.3. Circular Economy and E-Waste Management

The principles of the circular economy and effective e-waste management play crucial roles in the development and implementation of 6G networks. As technology evolves and the demand for electronic devices increases, it becomes imperative to adopt sustainable practices that minimize waste generation and maximize resource efficiency [51]. This section explores key aspects related to circular economy and e-waste management in the context of 6G, including end-of-life device recycling programs, reuse and refurbishment initiatives, and circular design principles for network equipment. These pillars contribute to reducing electronic waste, promoting resource conservation, and fostering a more sustainable and responsible approach to the lifecycle of network components and devices in the 6G ecosystem.

3.3.1. End-of-Life Device Recycling Programs

End-of-life device recycling programs hold significant importance in 6G networks. As the telecommunications industry moves towards the development and implementation of 6G technology, it is essential to address the environmental impact associated with the disposal of electronic devices specifically designed for 6G networks. 6G networks will involve the deployment of advanced devices, such as high-performance smartphones, IoT devices, and specialized network equipment. These devices will possess cutting-edge technologies and components, including advanced processors, high-resolution displays, and specialized antennas. As these devices reach their end-of-life stage, it becomes imperative to manage their disposal effectively to minimize environmental harm and promote sustainability.

3.3.2. Reuse and Refurbishment Initiatives

Reuse and refurbishment initiatives are vital components of sustainable practices in the context of 6G networks. These initiatives focus on extending the lifespan of electronic devices and network equipment by repairing, refurbishing, and redistributing them instead of disposing of them when they are no longer needed or functional. One of the key advantages of reuse and refurbishment initiatives is their ability to conserve valuable resources. By prolonging the use of electronic devices, the demand for raw materials and the associated environmental impact of resource extraction and manufacturing are significantly reduced. Reuse and refurbishment initiatives contribute to a circular economy approach where devices are kept in circulation for as long as possible, minimizing the need for new production and reducing the overall environmental footprint of the industry [52]. Furthermore, these initiatives play a crucial role in minimizing electronic waste. Discarded electronic devices, if not properly managed, can contribute to a significant amount of e-waste. By refurbishing and repairing devices, their useful life can be extended, reducing the amount of electronic waste generated. This is particularly important considering the rapid pace of technological advancements and the resulting high turnover rate of electronic devices. Reuse and refurbishment initiatives help mitigate the environmental and health hazards associated with improper e-waste disposal and the release of hazardous materials into the environment.

The global generation and recycling of electronic waste, or e-waste, in 2019 is shown in Figure 8. The majority of e-waste was generated in Asia, amounting to 24.9 million metric tons. On a per capita basis, however, Europe produced the highest amount of e-waste at 16.2 kg per person. Europe also boasted the highest documented rate of formally collecting and recycling e-waste, with a rate of 42.5%. In contrast, other continents had significantly lower rates of formally collected and recycled e-waste compared to their estimated e-waste generation. Presently, statistics indicate that in 2019, Asia ranked second in terms of e-waste generation, accounting for 11.7% of the global total. The Americas and Oceania followed closely at 9.4% and 8.8%, respectively, while Africa had the lowest contribution at 0.9%. It is important to note that these statistics can vary significantly across different regions due to various factors such as income levels, existing policies, and the structure of waste management systems. These factors play a significant role in shaping consumption and disposal behaviors. In the case of 6G devices, end-of-life recycling programs would involve the careful dismantling and disassembly of devices to separate various components and materials. The focus would be on recovering valuable resources such as precious metals, rare earth elements, and other critical materials used in the construction of these devices. Recycling technologies that maximize resource recovery and minimize environmental impact would be employed to extract these valuable materials efficiently. The procedure of device recycling is illustrated in Figure 9.

3.3.3. Circular Design Principles for Network Equipment

Circular design principles for network equipment in 6G networks prioritize resource efficiency, waste reduction, and responsible end-of-life management. These principles aim to optimize the lifespan and environmental impact of network equipment. Modularity is a key aspect, enabling easy repair and component replacement, extending the equipment’s lifespan, and reducing the need for complete replacements. Recyclability is another focus, ensuring that equipment is designed with recyclable materials for efficient recovery and reuse of resources. Easy disassembly further facilitates recycling processes. Energy efficiency is emphasized to reduce the overall energy footprint of network equipment. This involves using energy-efficient components, implementing smart power management systems, and employing advanced cooling technologies. Furthermore, circular design principles promote the reduction of hazardous materials, ensuring the safety of workers and end-users, as well as facilitating proper recycling and disposal. To implement circular design principles effectively, collaboration among stakeholders is vital. Device manufacturers, network operators, policymakers, and standards organizations need to work together to establish guidelines, standards, and incentives. Innovation and research in sustainable materials and manufacturing processes also play a significant role.

3.4. AI/ML Integration for the Future

AI/ML integration in wireless communication, as we approach the 6G era, extends its significance beyond technological advancement to embrace sustainability. These integrations offer opportunities to optimize resource usage, curtail energy consumption, and reduce the carbon footprint. Through smart power management, AI/ML dynamically adjusts power consumption in response to real-time network demands, fostering energy efficiency and minimizing waste. This resource-aware approach resonates with sustainability objectives, promoting responsible energy consumption [53,54]. Predictive maintenance driven by AI can further extend the lifespan of network equipment, reducing electronic waste. By identifying issues in real time and enabling timely repairs, AI/ML mitigates the need for premature equipment replacements, aligning with circular economy principles. AI/ML integration enables the development of context-aware and personalized services. By leveraging AI algorithms, wireless communication systems can gather contextual information about users, such as their locations, preferences, and behavior, to deliver personalized experiences. This enables the creation of tailored services and applications that cater to individual needs and provide highly relevant content and recommendations. For instance, AI-powered virtual assistants can understand user preferences, anticipate their requirements, and proactively provide personalized suggestions or assistance.

3.4.1. Intelligent Network Optimization and Automation

Intelligent network optimization and automation refer to the application of artificial intelligence (AI) and machine learning (ML) techniques to optimize and automate the management and operation of networks [55]. This approach aims to enhance network performance, improve efficiency, and reduce manual intervention in network operations. AI/ML algorithms can analyze large volumes of network data, including performance metrics, traffic patterns, and user behavior, to identify patterns, correlations, and anomalies. By learning from historical data, these algorithms can make accurate predictions and recommendations to optimize network performance. They can dynamically adjust network parameters such as routing, bandwidth allocation, load balancing, and resource management to ensure optimal utilization and improve overall network efficiency. Moreover, intelligent network optimization can enhance the quality of service (QoS) for end-users. AI/ML algorithms can learn from user behavior, preferences, and feedback to provide personalized and context-aware services. By understanding user demands and adapting network resources accordingly, the algorithms can ensure a seamless and satisfactory user experience. automation is another crucial aspect of intelligent network optimization. AI/ML algorithms can automate routine network management tasks, such as configuration, provisioning, fault detection, and troubleshooting. In fact, the entire 6G communication and networking protocol stack can be enhanced by leveraging AI, as illustrated in Figure 10. This reduces the dependence on manual intervention and frees up network administrators to focus on more complex and strategic tasks.

3.4.2. Context-Aware and Personalized Services

Context-aware services refer to the ability of the system to understand and utilize information about the user’s environment, location, time, social interactions, and other relevant factors. This contextual information can be obtained from various sources, such as sensors, IoT devices, user profiles, and historical data. AI/ML algorithms are employed to analyze this rich set of data and derive meaningful insights about the user’s context. With the availability of context information, 6G systems can deliver personalized services that cater to the specific requirements and preferences of individual users. AI/ML techniques play a crucial role in analyzing user behavior, preferences, and historical data to understand their needs and interests. This information is then utilized to provide personalized recommendations, content, and services. The integration of AI/ML in context-aware and personalized services is crucial for enabling the system to continuously learn and adapt to the evolving needs and preferences of users. By analyzing user feedback, behavior patterns, and contextual changes, the system can refine its understanding and improve the accuracy of personalized recommendations and services over time.

3.4.3. Cognitive Radio and Spectrum Management

Cognitive radio refers to a wireless communication system that can intelligently perceive and adapt to its operating environment by dynamically sensing and accessing available spectrum bands opportunistically. It is equipped with cognitive capabilities that allow it to monitor spectrum occupancy, detect unused or underutilized frequency bands, and opportunistically utilize them without causing harmful interference to licensed users [56]. In 6G, cognitive radio becomes even more crucial as the demand for wireless communication services continues to increase. With the proliferation of Internet of Things (IoT) devices, autonomous vehicles, and advanced multimedia applications, the radio spectrum has become a scarce resource. cognitive radio techniques, empowered by AI and ML algorithms, can address the spectrum scarcity challenge effectively. One of the key objectives of cognitive radio in 6G is spectrum management. This involves intelligent and dynamic allocation of spectrum resources to different users, applications, and services based on their requirements and priorities. AI/ML algorithms can learn from historical spectrum usage patterns, predict future demands, and optimize spectrum allocation in real time. This allows for the efficient sharing of spectrum resources among multiple users and enables dynamic spectrum access, ensuring optimal utilization and minimizing spectrum wastage.

4. The Landscape of 6G Technology Applications

4.1. Societal Equity

6G technology represents an unprecedented opportunity to uplift the lives of economically disadvantaged individuals, addressing societal inequalities and fostering inclusive progress [57]. For individuals living in poverty or economically challenging circumstances, 6G’s transformative potential can significantly impact various aspects of their daily lives, from agriculture and household management to education, healthcare, and overall well-being.

4.1.1. Agricultural Empowerment

In many developing regions, agriculture remains a primary source of income for impoverished communities. Here, 6G can play a pivotal role in empowering small-scale farmers with the knowledge and tools they need to improve their yields and economic prospects [58]. Through ultra-fast connectivity and real-time data access, farmers can receive updates on weather patterns, market prices, and agronomic best practices. This information equips them to make informed decisions, mitigate risks, and optimize resource use, ultimately leading to higher crop yields and increased income. With 6G-enabled precision agriculture, even farmers with limited access to traditional resources can participate in sustainable farming practices, improving food security and reducing poverty.

4.1.2. Enhancing Household Management

Housewives and homemakers in economically disadvantaged households often grapple with the dual challenge of managing limited resources and ensuring their family’s well-being. 6G can come to their aid by enabling smart home automation that conserves resources and streamlines daily tasks. Energy-efficient smart appliances, remotely controllable through 6G networks, can help reduce utility bills, making a significant saving on strained budgets. Furthermore, access to real-time information and delivery services enables cost-effective household management. For instance, knowing the latest prices and discounts can help in optimizing grocery spending, while timely notifications and reminders can enhance daily routines. In essence, 6G can bring a degree of efficiency and cost-effectiveness to household management that can be particularly meaningful for economically disadvantaged families.

4.1.3. Empowering Education for Children

Access to quality education is often a key determinant in breaking the cycle of poverty. 6G’s potential in education is transformational, as it can democratize learning opportunities and bridge educational divides. Children in underserved communities can benefit immensely from ultra-fast internet, gaining access to online educational resources, virtual classrooms, and interactive learning experiences. Educational content can be tailored to the specific needs and pace of individual students, ensuring that no child is left behind. This technology can be particularly impactful in regions with limited access to traditional educational infrastructure. Moreover, 6G can facilitate remote tutoring and mentoring, connecting students with teachers and experts from around the world, expanding their horizons, and opening up new avenues for future success.

4.1.4. Affordable Healthcare Access

For economically disadvantaged individuals, access to healthcare is often a pressing concern. 6G can be a lifeline, enabling affordable and accessible healthcare services. Telemedicine, powered by 6G’s high-speed connectivity and low latency, can bring medical consultations, diagnoses, and treatment recommendations to remote and underserved areas [59]. This means that even those living in poverty-stricken rural regions can receive timely medical attention, reducing the burden of healthcare costs and improving overall health outcomes. Moreover, telehealth services can provide preventative care and health education, empowering individuals and families to take charge of their well-being. This holistic approach to healthcare can have profound implications for poverty alleviation by reducing the financial burden associated with illness and increasing overall productivity.

4.1.5. Economic Empowerment of the Elderly

The elderly population in economically disadvantaged communities often faces limited access to healthcare and social services. 6G can change this reality by facilitating remote monitoring and care. Elderly individuals can receive regular health check-ups without leaving their homes, and caregivers can access real-time health data to provide personalized support. Furthermore, 6G’s connectivity can alleviate social isolation by enabling video calls and virtual gatherings with loved ones. For elderly individuals living in poverty or isolation, these services can improve mental and emotional well-being, enhancing their overall quality of life.

In the context of 6G, social sustainability takes on a new dimension, promising to bridge societal gaps and foster inclusive progress. With its transformative capabilities, 6G can act as a catalyst for social development by ensuring that the benefits of advanced technology reach all segments of society. By providing ultra-fast connectivity and real-time access to essential services like education and healthcare, 6G has the potential to democratize opportunities, empowering marginalized communities and reducing disparities. Furthermore, the technology’s capacity to facilitate virtual interactions and immersive experiences can strengthen social bonds, especially for those who may be geographically isolated or face mobility challenges. This inclusivity extends to employment opportunities as well, as 6G-enabled technologies can create new avenues for remote work, particularly benefiting individuals in regions with limited access to traditional job markets. In essence, 6G’s emphasis on social sustainability goes beyond technological advancement; it seeks to create a more equitable and connected society where the benefits of innovation are shared by all, regardless of their socioeconomic background or geographical location.

4.2. Holographic Communication

Holographic communication is an emerging technology that aims to revolutionize how we communicate and interact with others. It involves the transmission and display of three-dimensional holographic images, providing a more immersive and realistic experience compared to traditional two-dimensional communication methods. In holographic communication, advanced cameras and sensors capture the 3D information of a person or object from multiple viewpoints. This data is then processed, encoded, and transmitted to the receiving end using high-speed networks [60]. At the receiving end, specialized holographic displays render the transmitted information as dynamic and interactive holographic images. The goal of holographic communication is to create a sense of presence and enable remote participants to interact as if they were physically together. Imagine a scenario where individuals from different locations can engage in a teleconference and see each other as life-sized, realistic 3D holograms. This technology has the potential to transform industries such as teleconferencing, telemedicine, education, entertainment, and more. In teleconferencing, holographic communication can enhance collaboration by enabling participants to have face-to-face interactions with lifelike representations, improving non-verbal cues and overall communication effectiveness [61]. In telemedicine, doctors can examine patients remotely with the help of holographic displays that provide detailed 3D visualizations, enhancing diagnostic accuracy and enabling better patient care. Holographic communication also has exciting applications in education. Virtual classrooms can become more immersive and engaging as teachers and students interact as 3D holograms, making learning more interactive and personalized. Similarly, in the entertainment industry, holographic communication can bring virtual characters and objects to life, creating captivating and realistic experiences for the audience. To fully realize the potential of holographic communication, advancements are required in various areas. This includes the development of more efficient holographic capture and transmission technologies, advancements in holographic displays to improve image quality and realism, and the establishment of robust networks to handle the substantial data requirements of real-time holographic communication.

4.3. Autonomous Driving

6G aims to take it further by enabling even more advanced applications and capabilities. One area where 6G could have a significant impact is autonomous driving. Autonomous vehicles rely on fast and reliable communication networks to process vast amounts of data and make real-time decisions. With 6G, it is anticipated that autonomous driving will benefit from ultra-low latency, ultra-high reliability, and significantly increased data transmission rates. These advancements will enable vehicles to communicate with each other and with various elements of the transportation infrastructure, such as traffic lights, road sensors, and smart intersections, in a seamless and instantaneous manner. This enhanced connectivity will result in improved situational awareness, faster response times, and better overall safety on the roads [62,63]. Moreover, 6G could facilitate the exchange of rich sensor data, including high-resolution images and video, among autonomous vehicles, allowing them to create more detailed and accurate maps of the surroundings. Additionally, the increased capacity of 6G networks could support the deployment of edge computing and AI algorithms, enabling vehicles to process data locally and make intelligent decisions without relying heavily on cloud infrastructure. Overall, 6G has the potential to revolutionize the autonomous driving landscape by providing the necessary communication infrastructure to enhance safety, efficiency, and intelligence in self-driving vehicles. The crucial role of 6G in facilitating autonomous driving is illustrated in Figure 11.

4.4. Haptic Interaction with Machines

6G aims to provide even faster data transmission rates, lower latency, and enhanced connectivity compared to its predecessor, 5G. With theoretical speeds reaching terabits per second, 6G is envisioned to enable transformative applications and services. One significant aspect of 6G is its emphasis on haptic interaction with machines. Haptic interaction refers to the use of touch and force feedback to engage with and manipulate digital content or physical objects in a virtual or augmented reality environment. In the context of 6G, haptic interaction with machines envisions advanced interfaces that allow users to physically interact with remote systems, robots, or virtual objects. As shown in Figure 12, this technology involves the use of specialized devices such as haptic gloves or exoskeletons that provide tactile feedback, allowing users to feel and manipulate virtual objects as if they were physically present [64]. Haptic interaction can revolutionize various fields, including teleoperation, healthcare, gaming, and education. For example, in remote surgery, haptic feedback can provide surgeons with a realistic sense of touch, enabling precise and delicate procedures. In gaming, haptic interfaces can enhance immersion by allowing players to feel the impact of in-game actions. As 6G continues to evolve, haptic interaction with machines is expected to play a vital role in creating more realistic and interactive experiences, bridging the gap between the physical and virtual worlds.

4.5. Internet of Bio-Nano Things (IoBNT)

The Internet of Bio-Nano Things (IoBNT) is a concept that envisions the integration of nanotechnology, biotechnology, and the Internet of Things (IoT) to create a network of interconnected devices at the nano-bio scale. It represents a significant advancement in communication and computing, particularly when considering its potential implications in the context of 6G technology. IoBNT involves the development of nanoscale devices, such as sensors, actuators, and communication modules, that are capable of interacting with biological systems and the surrounding environment. These devices can be embedded in living organisms and human bodies or deployed in various environmental settings to collect and process data at the molecular level. The data generated by these devices can then be transmitted, analyzed, and utilized in real-time to enable a wide range of applications. In the context of 6G technology, IoBNT holds the promise of transforming various industries and sectors [65]. It could enable advanced healthcare systems, where nanoscale sensors integrated within the human body monitor vital signs, detect diseases at an early stage, and provide personalized treatment options. Additionally, IoBNT can facilitate environmental monitoring by deploying nanosensors in ecosystems to gather data on pollution levels, climate change, and biodiversity. The integration of IoBNT with 6G technology would also open up new possibilities in areas such as agriculture, manufacturing, and energy. For instance, nanoscale devices can monitor crop health, optimize resource utilization, and enhance agricultural productivity. In manufacturing, IoBNT can enable real-time monitoring and control of production processes at the molecular level, leading to improved efficiency and quality. Furthermore, by integrating nanogenerators and energy harvesting technologies, IoBNT can contribute to the development of self-powered and sustainable systems. However, it is essential to consider the challenges and ethical implications associated with IoBNT and 6G. Ensuring privacy, security, and the responsible use of this technology are critical aspects that need to be addressed. Additionally, the development of IoBNT requires interdisciplinary collaboration among experts in nanotechnology, biology, telecommunications, and ethics to ensure its safe and beneficial deployment. In summary, the integration of IoBNT with 6G technology holds tremendous potential to revolutionize various industries and domains by enabling precise monitoring, control, and communication at the molecular level. It represents a convergence of cutting-edge technologies that can pave the way for a more connected, efficient, and personalized future.

4.6. Industry 4.0 and Beyond

Industry 4.0, also known as the Fourth Industrial Revolution, is a term used to describe the ongoing transformation of traditional industries through the integration of digital technologies and automation. Industry 4.0 involves the convergence of myriad technologies such as sensor networks, Internet of Things (IoT), AI, big data analytics, cloud computing, and robotics to create smart, interconnected systems that can operate autonomously and optimize production processes. Industry 4.0 brings significant advancements in manufacturing, supply chain management, and other sectors, leading to increased productivity, efficiency, and customization. It enables the collection and analysis of vast amounts of data from sensors and connected devices, facilitating real-time decision-making and predictive maintenance. Smart factories equipped with intelligent systems can streamline operations, minimize downtime, and enhance product quality. However, as technology continues to advance, there is growing anticipation for the next phase beyond Industry 4.0. This is where 6G enters the picture, as depicted in Figure 13. While 6G is still being deployed globally, researchers and experts are already exploring the possibilities and potential capabilities of 6G. 6G is envisioned as a transformative technology that will enable even faster and more reliable wireless communication. It aims to provide unprecedented data speeds, ultra-low latency, massive connectivity, and enhanced network intelligence. With 6G, it is anticipated that data rates could reach terabits per second, enabling near-instantaneous transmission and processing of vast amounts of data [66]. In the context of Industry 4.0 and beyond, 6G could unlock new opportunities and enable a range of applications that were previously unimaginable. It could support the seamless integration of IoT devices, robotics, and AI systems in various industries, facilitating real-time data sharing, intelligent decision-making, and autonomous operations on a much larger scale. 6G’s low latency and high reliability could be crucial in critical applications such as remote surgery, autonomous vehicles, and advanced industrial automation. It could enable precise control and communication between machines, leading to more efficient and synchronized production processes. 6G stands to unlock a new frontier of possibilities, particularly in terms of sustainability. Its low latency and high reliability are poised to underpin critical applications like remote surgery, autonomous vehicles, and advanced industrial automation, ensuring safety and precision. Moreover, 6G’s extensive connectivity potential could facilitate the widespread deployment of sensor networks, revolutionizing monitoring and optimization practices across diverse sectors, thereby reinforcing the sustainable evolution of industries.

4.7. Extended Reality (XR)

Extended reality (XR) is an umbrella term that encompasses various immersive technologies, including virtual reality (VR), augmented reality (AR), and mixed reality (MR). It combines the physical and virtual worlds to create a rich, interactive experience beyond what is possible with traditional displays. XR has the potential to revolutionize many industries and domains, from entertainment and gaming to healthcare, education, and enterprise applications [67]. As for the connection between XR and 6G, 6G is expected to succeed 5G in the future. While specific details about 6G are still being researched and defined, it is anticipated that it will bring unprecedented capabilities in terms of speed, latency, capacity, and connectivity. This enhanced wireless infrastructure will significantly benefit XR applications, enabling even more immersive and seamless experiences. With the integration of XR and 6G, we can envision several advancements and possibilities:

• Enhanced Immersion: XR experiences will become even more realistic and immersive with 6G. Faster and more stable wireless connections will enable higher resolution, smoother graphics, and reduced latency, resulting in a heightened sense of presence and interactivity.
• Mobile XR: 6G is expected to provide ubiquitous and ultra-fast connectivity, allowing users to experience XR applications seamlessly on their mobile devices. This means that users will have the freedom to engage with XR content wherever they are without relying on wired connections or specific hardware.
• Massive Connectivity: XR experiences often require multiple devices and users to interact in real time. 6G’s ability to support massive device connectivity will enable XR applications to seamlessly connect a large number of users and devices simultaneously, leading to collaborative and social XR experiences on a much larger scale.
• Cloud-based XR: With the high bandwidth and low latency offered by 6G, more processing and rendering tasks can be offloaded to cloud servers. This cloud-based approach to XR can reduce the computational requirements on end-user devices, making XR experiences more accessible to a wider range of devices and potentially lowering costs.
• Edge Computing: 6G’s emphasis on edge computing can bring XR closer to users by leveraging edge nodes and edge servers. This enables faster processing and response times, reducing latency and enhancing the overall XR experience, particularly in scenarios where real-time interaction and data processing are critical.
• Ubiquitous Spatial Computing: XR applications rely on spatial computing to understand and interact with the physical environment. With 6G’s advancements, spatial computing capabilities can extend beyond localized areas to cover larger regions, facilitating seamless transitions between physical and virtual spaces and enabling XR applications to have a deeper understanding of the user’s surroundings.

4.8. Wireless Brain–Computer Interaction

Wireless brain-computer interaction (BCI) refers to the seamless integration of brain-computer interfaces with wireless communication technologies, enabling direct and wireless communication between the human brain and external devices or networks. As we look ahead to the future of wireless communication with the advent of 6G, there are exciting possibilities for the advancement of BCI technology. 6G is expected to offer unprecedented speed, capacity, and low-latency connectivity. These advancements can greatly enhance BCI applications by enabling real-time, high-bandwidth, and reliable wireless transmission of brain signals [68,69]. With wireless BCI and 6G, we can envision a wide range of innovative applications. For instance, individuals with motor disabilities could control prosthetic limbs or robotic devices wirelessly, with seamless communication between their brain signals and external devices. This could lead to improved mobility and independence for those with physical limitations. Moreover, wireless BCI combined with 6G can revolutionize healthcare. Brain signals could be wirelessly transmitted to medical professionals or AI systems, allowing for remote diagnosis, monitoring, and treatment of neurological conditions. This could be particularly beneficial in remote or underserved areas where access to specialized healthcare is limited. Additionally, the integration of wireless BCI and 6G can bring about advancements in virtual and augmented reality experiences. Users could interact with virtual environments or control augmented reality devices directly through their brain signals without the need for cumbersome physical interfaces. This could create immersive and natural user interfaces, enhancing the way we interact with digital content. However, it is essential to consider the ethical and privacy implications of wireless BCI in the 6G era. As brain signals are transmitted wirelessly, ensuring the security and privacy of such sensitive data becomes paramount. Robust encryption and authentication mechanisms will need to be implemented to protect user privacy and prevent unauthorized access to neural information. Figure 14 shows a scenario of brain–computer interaction enabled by 6G. In conclusion, wireless brain–computer interaction combined with the capabilities of 6G wireless communication opens up tremendous opportunities for transformative applications. From healthcare to assistive technologies and immersive experiences, this integration holds the potential to enhance our lives and push the boundaries of human–machine interaction. However, careful consideration of ethical and privacy concerns is crucial as we navigate this exciting frontier.

5. Materials and Methods

5.1. The Quintuple Helix Model Whitepaper

The quintuple helix model, as described by Carayannis et al. [70], provides a framework for understanding the interplay between various subsystems in society to support sustainable development. This model categorizes the subsystems into five helices: the political system, the education system, the economic system, the natural environment, and the media- and culture-based public society (civil society). Each helix possesses its own assets or capital, which are formed within the helix itself and influenced by the actions within that subsystem. Knowledge is seen as a resource that circulates between the subsystems, transforming into innovation and know-how for society and the economy. The quintuple helix model recognizes the interconnectedness of these subsystems, where knowledge acts as both an input and output, fostering the creation of new knowledge and inventions. The education system encompasses all levels of education, with its assets embodied in individuals who undergo education as students or work within the system as teachers, researchers, and more. The economic system consists of various elements that form the economic structure, including institutions, industries, companies, services, and banks. Its asset is economic capital, encompassing machinery, production processes, resources, and money. The natural environment’s asset is natural capital, which encompasses nature itself and its resources, such as soil, water, air, living organisms, minerals, and metals. The media- and culture-based public society subsystem combines civil society and media assets, incorporating information, social capital, television, newspapers, information-sharing networks, art, traditions, values, and lifestyles. The political system’s assets comprise political and legal capital. Political capital refers to the accumulation of resources and power by politicians, parties, and stakeholders, while legal capital represents the legal system, laws, and regulations.

According to the quintuple helix model, knowledge circulation occurs not only within a nation state but also between states. This model recognizes the interconnectedness and circulation of knowledge on different levels, crossing national boundaries. When examining the sustainable development of 6G, the quintuple helix model helps identify relevant megatrends that extend beyond nation states. This is illustrated in Figure 15. Therefore, understanding the quintuple helix model is crucial at both the national level and when considering the cross-boundary implications.

5.2. 6G End-to-End Architecture

The proposed system-level end-to-end (E2E) architecture for 6G is designed to revolutionize wireless communications by incorporating key enablers across various domains [71]. Building upon the advancements of previous generations, 6G aims to provide extremely high data rates, distributed massive MIMO systems, enhanced localization and sensing capabilities, intelligent network management, flexibility, efficiency, and effective service orchestration. To support the exponential growth of data-intensive applications, 6G emphasizes extremely high data rate radio links, enabling multi-gigabit per second data rates for seamless user experiences. Distributed massive MIMO systems leverage large-scale antenna arrays to improve spectral efficiency and system capacity, facilitating higher data rates and better performance. Localization and sensing play a crucial role in 6G, enabling precise positioning and context-aware services. With highly accurate and low-latency localization, users can benefit from applications such as accurate navigation and location-based augmented reality. Sensing capabilities allow for environmental data collection, facilitating intelligent decision-making and network resource optimization. The burgeoning quantum computing is expected to contribute in many ways, particularly in the security area.

Programmability is a key enabler for efficient and intelligent network management in 6G. Network programmability enables dynamic configuration and optimization based on diverse use cases and their key value indicators (KVIs) or key performance indicators (KPIs). User equipment (UE) programmability empowers users to customize their devices, fostering faster innovation and time to market. Automation reduces human errors in network management and operations, while AI and AI as a Service enhance intelligence throughout the network. The AI-enabled architecture supports distributed AI services, bringing AI closer to the applications and reducing latency. Cloudification trends enable novel network designs, allowing 6G to fully utilize and interact with the cloud platform. This interaction allows for intelligent resource allocation, further reducing the environmental footprint. Sustainability is at the core of these innovations, contributing to more eco-conscious, resource-efficient, and responsible network operations. Flexibility is ensured through the deployment of campus networks, non-terrestrial networks (NTNs), and mesh networks. Campus networks cater to specific education environments. Non-terrestrial networks comprise satellites, high-altitude platform stations (HAPSs), air-to-ground stations, and unmanned aerial vehicles (UAVs). NTNs complement terrestrial networks and allow access to remote sites and above oceans. However, they pose particular challenges, as revealed in [72]. Mesh networks coupled with cloudification offer decentralized and distributed topologies. Efficient network design is achieved through cloudification, facilitating resource optimization, virtualization, network slicing, and dynamic service deployment. Service management and orchestration are crucial, employing the concept of “Device-Edge-Cloud Continuum Orchestration” to ensure seamless integration of devices, edge computing, and cloud infrastructure. Figure 16 shows the overall end-to-end architecture of 6G and the key components.

5.3. Enhanced Blend of Massive Machine-Type Communication (mMTC) and URLLC

In the context of 6G networks, an enhanced blend of massive machine-type communication (mMTC) and ultra-reliable low-latency communication (URLLC) is expected to play a crucial role in shaping the future of wireless communication systems. mMTC focuses on supporting a massive number of connected devices and sensors, enabling the Internet of Things (IoT) to unleash its full potential [73]. On the other hand, URLLC aims to provide ultra-reliable and low-latency communication links critical for applications such as autonomous vehicles [74], remote surgery, and industrial automation. The integration of mMTC and URLLC in 6G networks will involve creating a highly efficient and flexible communication infrastructure capable of handling diverse requirements. One aspect involves optimizing the allocation of network resources to support the massive connectivity demanded by mMTC. This may involve advanced techniques such as dynamic spectrum access, improved interference management, and efficient scheduling algorithms to ensure efficient utilization of available resources. Moreover, to achieve ultra-reliable and low-latency communications, URLLC requirements need to be met. This entails minimizing communication latency, enhancing reliability, and reducing packet loss rates. Techniques like advanced coding and modulation schemes, ultra-dense small-cell networks, and multi-access edge computing (MEC) can be employed to improve latency, reliability, and overall network performance. Additionally, with 6G, it is expected that advanced technologies like AI and ML will be further integrated into mMTC and URLLC systems.

AI and ML algorithms can enable intelligent resource allocation, adaptive beamforming, and proactive network management, optimizing the performance of both mMTC and URLLC communications. This integration can also enhance the network’s ability to handle diverse applications, adapt to dynamic conditions, and provide real-time optimization for latency-sensitive tasks. Overall, the enhanced blend of mMTC and URLLC in 6G networks promises to deliver a highly connected, reliable, and responsive communication infrastructure capable of supporting a wide range of applications, as illustrated in Figure 17. From smart cities and autonomous transportation to advanced industrial automation and immersive virtual reality experiences, this integration will enable transformative advancements in various sectors, ultimately shaping the future of communication and technology.

6. Future Research Challenges and Opportunities

6G features a highly heterogeneous network structure. Diverse access techniques such as OFDMA and NOMA support the network structure and facilitate the integration of diverse networks, including terrestrial, non-terrestrial, and underwater networks, into a three-dimensional network [75]. Conventional cloud radio access network (C-RAN) is insufficiently scalable for 6G networks. Hence, new architectures and technologies are needed for the integration of a variety of networks and to allow proper and scalable management of such networks. Figure 18 shows the breakdown of the section. A rich suite of learning-driven optimization techniques such as multi-objective machine learning, deep reinforcement learning, federated learning, transfer learning, metaheuristics, multi-task learning, and multiple gradient descent design can simplify the formidable task. These techniques are used to optimize various components of 6G networks, such as bandwidth efficiency, power efficiency, and delay optimization, and there is a paradigm shift towards multi-component Pareto optimization in 6G networks.

The comparative

Table 8. Comparison of the current paper with previous works.

Paper Title	Objective	Method	Research Gap	ESG/SDG * Alignment
Edge Artificial Intelligence for 6G: Vision, Enabling Technologies, and Applications [19]	Provide a comprehensive understanding of edge AI for 6G networks.	Given	Need for scalable and trustworthy edge AI systems in 6G networks.	Did not mention ESG and SDG.
Sixth-Generation (6G) Wireless Networks: Vision, Research Activities, Challenges, and Potential Solutions [10]	Examine the vision, research activities, challenges, and potential solutions for 6G wireless networks.	Given	Lack of architectural diagrams for the proposed methodology.	Did not mention ESG; Explicitly aligned with SDG
Sustainability as a Challenge and Driver for Novel Ecosystemic 6G Business Scenarios [22]	Develop future scenarios for sustainable 6G business strategies and analyze them from a business model perspective.	Given	Need for more foresight research on ecosystemic business models in 6G context.	Aligned with both ESG and SDG.
Survey on 6G Frontiers: Trends, Applications, Requirements, Technologies, and Future Research [13]	Comprehensively survey the path towards 6G networks, covering trends, applications, requirements, technologies, projects, research work, standardization, and future research directions.	Not given	Lack of comprehensive survey on the overall development of 6G networks.	Did not mention ESG; Explicitly aligned with SDG.
6G Enabled Smart Infrastructure for Sustainable Society: Opportunities, Challenges, and Research Roadmap [18]	Provide an overview of opportunities, challenges, and research roadmap for implementing 6G-enabled smart infrastructure for a sustainable society.	Not given	Lack of comprehensive analysis of social, psychological, and health challenges in 6G.	Aligned with both ESG and SDG.
White Paper on Broadband Connectivity in 6G [21]	Explore the implementation of broadband connectivity in future 6G wireless systems.	Given	Need for full-coverage broadband connectivity in rural areas.	Did not mention ESG and SDG.
A Vision of 6G Wireless Systems: Applications, Trends, Technologies, and Open Research Problems [14]	Present a holistic vision for 6G wireless systems, including drivers, service classes, enabling technologies, and research agenda.	Not given	Undefined fundamental architectural and performance components of 6G wireless systems.	Did not mention ESG and SDG.
Towards 6G Internet of Things: Recent advances, use cases, and open challenges [17]	Provide a comprehensive survey of the state-of-the-art 6G wireless communication, recent advances, use cases, and open challenges.	Not given	Need for a dynamic architecture in 6G.	Did not mention ESG and SDG.
6G Wireless Communication Systems: Applications, Requirements, Technologies, Challenges, and Research Directions [9]	Explore the vision, technologies, challenges, and research directions for 6G wireless communication with AI integration.	Not given	Need for higher system capacity, data rate, lower latency, and improved QoS compared to 5G.	Did not mention ESG and SDG.
Connecting the Remaining 4 Billion: A Survey on Rural Connectivity [1]	Explore technologies and strategies for providing connectivity to rural areas and addressing the challenge of connecting the remaining four billion people.	Given	Lack of a detailed survey dedicated to the latest solutions for rural connectivity.	Did not mention ESG; Explicitly aligned with SDG.
From Efficiency to Sustainability: Exploring the Potential of 6G for a Greener Future	Explore sustainable solutions for 6G wireless communication systems, focusing on energy-efficient approaches and environmental sustainability for a smooth transition from 5G to 6G	Given	–	Aligns with both ESG and SDG.

* ESG stands for Environmental, social and governance; SGD stands for Sustainable Development Goal.

serves as a valuable reference point for assessing and comparing a diverse collection of research papers in the field of next-generation wireless communication, particularly focusing on 6G networks and related technologies. The table encompasses essential aspects of each research paper, including objective, methodology, research gap, and alignment with ESG/SDG. The last row highlights the novelty of this work.

6.1. Sustainablity Challenges and Solutions

The rapid proliferation of wireless communication technologies, coupled with the exponential growth in data consumption, has raised significant concerns about their environmental impact [76]. As the world transitions towards a more sustainable future, it is crucial to address the challenges posed by energy consumption and environmental degradation. In the context of 6G wireless communication, several sustainability challenges emerge, accompanied by innovative solutions that hold the potential to mitigate their effects [77,78].

6.1.1. Energy-Efficient Scalability

Challenge—One of the primary concerns with the evolution of wireless communication is the energy efficiency of networks as they scale to accommodate a massive number of devices and higher data rates. As 6G networks continue to expand to serve an increasingly interconnected world, there is a risk of energy consumption spiraling out of control.

Opportunity—To address this challenge, research must focus on developing energy-efficient technologies that can seamlessly scale with the network’s growth. Techniques such as dynamic power allocation, intelligent sleep modes, and adaptive modulation can help optimize energy consumption based on network load and device requirements. Moreover, the integration of renewable energy sources, such as solar and wind, into network infrastructure could contribute to sustainable scalability.

6.1.2. Green Network Slicing

Challenge—Network slicing, a key feature of 6G, allows multiple virtual networks to coexist on a shared physical infrastructure. However, the challenge lies in dynamically allocating resources while minimizing energy consumption and carbon emissions across different slices.

Opportunity—Researchers can explore AI-driven algorithms that intelligently allocate resources to different slices based on real-time demand and energy efficiency criteria. By optimizing the allocation of radio resources, computing power, and energy consumption, green network slicing can ensure that resources are used effectively, reducing energy waste and promoting sustainability.

6.1.3. Dynamic Spectrum Management

Challenge—Optimizing spectrum utilization is essential for reducing energy consumption and ensuring efficient communication. Traditional static spectrum allocation methods can lead to inefficient usage and unnecessary energy consumption.

Opportunity—Dynamic spectrum management techniques, such as spectrum sharing and cognitive radio, can dynamically allocate spectrum based on real-time demand. Cognitive radio systems, for instance, enable devices to intelligently select and utilize available spectrum, thereby reducing interference and energy consumption. Exploring advanced spectrum access protocols and policies can lead to more sustainable spectrum usage.

6.1.4. Lifecycle Carbon Footprint

Challenge—Assessing the overall environmental impact of 6G technology requires considering the entire lifecycle of devices and infrastructure components, from raw material extraction to manufacturing, usage, and disposal.

Opportunity—Researchers can conduct comprehensive lifecycle assessments to quantify the carbon footprint of 6G networks and devices. This analysis can guide decisions in design, manufacturing, and disposal processes, aiming to minimize environmental impact. Collaborative efforts between manufacturers, policymakers, and environmental experts can lead to the development of eco-friendly materials, efficient recycling practices, and responsible disposal methods.

6.2. Technological Hurdles and Innovations

As the evolution of wireless communication technologies progresses towards 6G, addressing technological challenges and fostering innovations becomes paramount. The fusion of technological advancements with sustainability principles can lead to the development of environmentally friendly and energy-efficient 6G systems [79,80].

6.2.1. Ultra-Low-Power Components

Challenge—The demand for higher data rates and ultra-low latency in 6G systems can lead to increased power consumption, offsetting potential gains in energy efficiency.

Opportunity—Researchers and engineers can focus on developing ultra-low-power hardware components, including transceivers, processors, and sensors. This involves optimizing the design and fabrication of microchips to reduce power consumption while maintaining performance. Techniques like voltage scaling, power gating, and energy-efficient architectures can contribute to minimizing the energy footprint of 6G devices.

6.2.2. Novel Materials for Sustainability

Challenge—The manufacturing and deployment of wireless communication infrastructure can have a significant environmental impact due to the use of resource-intensive materials.

Opportunity—Investigating novel, eco-friendly materials for manufacturing 6G components can lead to reduced environmental impact. Researchers can explore materials with lower energy requirements for extraction and production, as well as materials that are biodegradable or recyclable. By integrating sustainable materials into antenna design, circuit boards, and device housings, the overall environmental footprint can be lowered.

6.2.3. Self-Powered Networks

Challenge—The energy consumption of wireless networks remains a critical concern. Traditional energy sources may not suffice for providing continuous power to 6G infrastructure and devices.

Opportunity—Research efforts can focus on energy harvesting techniques that convert ambient energy sources, such as solar radiation, radio frequency signals, and vibrations, into usable power. Wireless charging technologies can be integrated into the network to enable devices to harvest energy from the environment. This approach reduces the reliance on conventional energy sources and enhances the sustainability of 6G networks.

6.2.4. Green Computing Techniques

Challenge—As 6G systems enable complex applications and services, the data processing demands increase, leading to higher energy consumption in data centers and edge devices.

Opportunity—Green computing approaches, including energy-efficient algorithms, data compression, and edge computing, can mitigate energy consumption in data processing. Algorithms that optimize data transmission reduce redundancy, and minimize computation complexity can lower energy requirements. Edge computing, where data is processed closer to the source, reduces the need for centralized data centers and can lead to more energy-efficient operations.

6.3. Application-Specific Research Directions

The transformative potential of 6G extends beyond enhanced communication capabilities; it opens doors to novel applications that can drive sustainability across various sectors. By aligning 6G technology with specific application domains, researchers can explore innovative solutions that contribute to a greener and more sustainable future [81,82].

6.3.1. Sustainable IoT Ecosystems

Opportunity—6G’s ultra-low latency and massive connectivity capabilities offer an unprecedented opportunity to create sustainable Internet of Things (IoT) ecosystems. These ecosystems can drive efficiency in industries such as agriculture, environmental monitoring, and supply chain management.

Research Direction—Researchers can investigate the design of resource-efficient IoT solutions that minimize energy consumption while maximizing data collection accuracy. By optimizing communication protocols, data aggregation, and sensor networks, 6G-enabled IoT systems can enable precise monitoring and effective resource management, thereby contributing to sustainable practices.

6.3.2. Green Autonomous Systems

Opportunity—Autonomous systems, including drones, robots, and autonomous vehicles, have the potential to revolutionize industries, but their energy demands pose challenges to sustainability.

Research Direction—Explore how 6G technology can enable efficient and intelligent communication between autonomous systems and their control centers. Investigate energy-efficient communication protocols, decentralized decision-making algorithms, and collaborative behavior strategies to enhance the overall energy efficiency of autonomous systems. Additionally, integrating renewable energy sources into autonomous systems can contribute to their sustainability.

6.3.3. Energy-Aware XR Experiences

Opportunity—Extended reality (XR) technologies, such as virtual reality (VR) and augmented reality (AR), offer immersive experiences but often require high computational resources and energy consumption.

Research Direction—Examine how 6G’s ultra-low latency and high data rates can enhance XR experiences while minimizing energy usage. Develop XR rendering techniques that dynamically adjust visual fidelity based on available resources and user preferences. Moreover, investigate collaborative XR environments where users share experiences in real time, reducing the need for individual high-end devices and lowering energy consumption.

6.3.4. Health and Environmental Monitoring

Opportunity—6G’s connectivity and data capabilities enable real-time health and environmental monitoring, fostering sustainable living and early detection of issues.

Research Direction—Explore the integration of wearable devices and sensors with 6G networks to enable continuous health monitoring and environmental sensing. It is important to develop predictive models that utilize real-time data to identify patterns and anomalies, allowing for timely interventions and sustainable decision-making. Collaboration with healthcare and environmental experts facilitates the design of integrated systems that promote wellness and resource conservation.

6.4. Ethical, Social, and Policy Considerations

While the development of 6G technology holds immense promise for a greener future, it also brings forth ethical, social, and policy challenges that require careful consideration to ensure equitable and sustainable deployment [18,83].

6.4.1. Digital Divide Mitigation

Challenge—The rapid adoption of new technologies can exacerbate existing digital divides, leaving marginalized communities with limited access to the benefits of 6G.

Opportunity—Policymakers, industry stakeholders, and researchers must collaborate to ensure that 6G infrastructure is deployed inclusively, bridging the digital divide. Initiatives such as subsidized access, community networks, and educational programs can promote equitable access to 6G’s benefits and prevent social disparities from widening.

6.4.2. Privacy and Data Security

Challenge—The proliferation of connected devices and data-intensive applications in the 6G era raises concerns about data privacy and security breaches.

Opportunity—Ethical design and robust security mechanisms are essential. Researchers should explore encryption techniques, secure authentication methods, and decentralized data storage to safeguard user information. Additionally, regulations and policies should be established to protect users’ privacy rights, including consent mechanisms and data ownership frameworks.

6.4.3. E-Waste Management Strategies

Challenge—The rapid pace of technological advancement may lead to a surge in electronic waste (e-waste) as outdated 6G devices and infrastructure become obsolete.

Opportunity—To address this challenge, governments and industries must implement comprehensive e-waste management strategies. These may include mandatory recycling programs, extended producer responsibility, and incentivizing the design of modular and upgradable devices. Collaboration between technology manufacturers, recycling facilities, and policymakers can ensure responsible disposal and recycling practices.

6.5. Collaborative Initiatives and International Cooperation

The successful integration of 6G technology for sustainability requires a global effort involving collaboration between stakeholders across various sectors and geographical boundaries. By fostering international cooperation and establishing collaborative initiatives, the potential of 6G can be harnessed to drive positive environmental and societal outcomes [84,85].

6.5.1. Global Standards and Regulations

Opportunity—The development of global standards and regulations for 6G is crucial to ensure interoperability, fair competition, and environmentally responsible deployment.

Initiative—International bodies, governments, and industry associations should collaborate to establish unified standards and regulations for 6G technology. These standards can encompass energy efficiency benchmarks, spectrum allocation guidelines, and environmental impact assessments. By setting clear guidelines, the global 6G ecosystem can operate cohesively and in line with sustainability objectives.

6.5.2. Cross-Sector Partnerships

Opportunity—The convergence of 6G with various sectors, such as energy, transportation, and healthcare, offers unique opportunities for cross-sector partnerships.

Initiative—Encourage collaboration between industries, academia, and governments to explore interdisciplinary solutions. For example, partnerships between telecommunications companies and renewable energy providers can lead to the development of sustainable, off-grid communication infrastructure. Cross-sector collaborations can result in innovative applications that benefit both technology advancement and sustainability goals.

6.5.3. Knowledge Sharing and Capacity Building

Opportunity—Promoting knowledge sharing and capacity building can empower individuals, organizations, and governments to harness 6G’s potential for sustainability.

Initiative—Establish training programs, workshops, and knowledge-sharing platforms to educate stakeholders about 6G’s capabilities and its role in addressing sustainability challenges. Collaborate with educational institutions and non-governmental organizations to disseminate information and build expertise. By fostering a deeper understanding of 6G’s potential, society can collectively work towards responsible and sustainable 6G deployment.

These research challenges and opportunities require interdisciplinary collaborations among researchers/experts from different fields, such as wireless communications, networking, computing, environment, and artificial intelligence.

7. Conclusions

This paper has explored the evolution of wireless communication technologies from 5G to the prospective 6G, with a specific focus on its potential to drive sustainability and usher in a greener future. Through an examination of key drivers shaping the 6G landscape, ranging from energy efficiency and sustainable infrastructure to circular economy principles and AI/ML integration, the paper underscores the transformative potential of 6G in addressing the environmental challenges posed by modern telecommunications. The paper also delves into diverse applications that stand to benefit from the advent of 6G technology, including holographic communication, autonomous driving, haptic interaction with machines, Internet of Bio-Nano Things (IoBNT), Industry 4.0, extended reality (XR), and wireless brain–computer interaction. These applications not only signify technological advancements but also hold promise in contributing to sustainable development across various sectors. By examining the quintuple helix model whitepaper, the 6G end-to-end architecture, and the blending of mMTC and URLLC, the paper provides a methodological underpinning for understanding the intricate fabric of 6G research and development.

As the journey toward 6G unfolds, it is important to acknowledge the multitude of challenges and opportunities that lie ahead. The path to a greener and more sustainable future through 6G technology demands continued interdisciplinary collaboration, innovative research, and responsible implementation. Stakeholders, including researchers, policymakers, and industry leaders, must collectively address challenges related to energy consumption, infrastructure deployment, e-waste management, and ethical considerations surrounding AI integration. In the years to come, further exploration of these themes, coupled with continued dedication to environmentally conscious innovation, will be essential in harnessing the full potential of 6G technology for a harmonious coexistence between advanced connectivity and ecological preservation. The strides made in the realm of 6G have the power to redefine the landscape of sustainable development, serving as a testament to human ingenuity and a commitment to a greener, more interconnected, and sustainable future.