The fifth generation (5G) wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability, and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation (6G) wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle (UAV) communication networks, thus achieving a space-air-ground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6 GHz, millimeter wave (mmWave), terahertz (THz), and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence (AI) and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.

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Towards 6G wireless communication networks: vision, enabling technologies, and new paradigm shifts

Emerging applications such as Internet of Everything, Holographic Telepresence, collaborative robots, and space and deep-sea tourism are already highlighting the limitations of existing fifth-generation (5G) mobile networks. These limitations are in terms of data-rate, latency, reliability, availability, processing, connection density and global coverage, spanning over ground, underwater and space. The sixth-generation (6G) of mobile networks are expected to burgeon in the coming decade to address these limitations. The development of 6G vision, applications, technologies and standards has already become a popular research theme in academia and the industry. In this paper, we provide a comprehensive survey of the current developments towards 6G. We highlight the societal and technological trends that initiate the drive towards 6G. Emerging applications to realize the demands raised by 6G driving trends are discussed subsequently. We also elaborate the requirements that are necessary to realize the 6G applications. Then we present the key enabling technologies in detail. We also outline current research projects and activities including standardization efforts towards the development of 6G. Finally, we summarize lessons learned from state-of-the-art research and discuss technical challenges that would shed a new light on future research directions towards 6G.

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Survey on 6G Frontiers: Trends, Applications, Requirements, Technologies and Future Research

Blockchain for 5G and beyond networks: A state of the art survey

The sixth-generation (6G) wireless communication network is expected to integrate the terrestrial, aerial, and maritime communications into a robust network which would be more reliable, fast, and can support a massive number of devices with ultra-low latency requirements. The researchers around the globe are proposing cutting edge technologies such as artificial intelligence (AI)/machine learning (ML), quantum communication/quantum machine learning (QML), blockchain, tera-Hertz and millimeter waves communication, tactile Internet, non-orthogonal multiple access (NOMA), small cells communication, fog/edge computing, etc., as the key technologies in the realization of beyond 5G (B5G) and 6G communications. In this article, we provide a detailed overview of the 6G network dimensions with air interface and associated potential technologies. More specifically, we highlight the use cases and applications of the proposed 6G networks in various dimensions. Furthermore, we also discuss the key performance indicators (KPI) for the B5G/6G network, challenges, and future research opportunities in this domain.

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The shift to 6G communications: vision and requirements

The Shift to 6G Communications: Vision and Requirements

With the deployment of fifth-generation (5G) wireless networks worldwide, research on sixth-generation (6G) wireless communications has commenced. It is expected that 6G networks can accommodate numerous heterogeneous devices and infrastructures with enhanced efficiency and security over diverse, e.g. spectrum, computing and storage, resources. However, this goal is impeded by a number of trust-related issues that are often neglected in network designs. Blockchain, as an innovative and revolutionary technology that has arisen in the recent decade, provides a promising solution. Building on its nature of decentralization, transparency, anonymity, immutability, traceability and resiliency, blockchain can establish cooperative trust among separate network entities and facilitate, e.g. efficient resource sharing, trusted data interaction, secure access control, privacy protection, and tracing, certification and supervision functionalities for wireless networks, thus presenting a new paradigm towards 6G. This paper is dedicated to blockchain-enabled wireless communication technologies. We first provide a brief introduction to the fundamentals of blockchain, and then we conduct a comprehensive investigation of the most recent efforts in incorporating blockchain into wireless communications from several aspects. Importantly, we further propose a unified framework of the blockchain radio access network (B-RAN) as a trustworthy and secure paradigm for 6G networking by utilizing blockchain technologies with enhanced efficiency and security. The critical elements of B-RAN, such as consensus mechanisms, smart contract, trustworthy access, mathematical modeling, cross-network sharing, data tracking and auditing and intelligent networking, are elaborated. We also provide the prototype design of B-RAN along with the latest experimental results.

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Blockchain-enabled wireless communications: a new paradigm towards 6G.

The continually rising demand for wireless services and applications in the era of Internet of things (IoT) and artificial intelligence (AI) presents a significant number of unprecedented challenges to existing network structures. To meet the rapid growth need of mobile data services, blockchain radio access network (B-RAN) has emerged as a decentralized, trustworthy radio access paradigm spurred by blockchain technologies. However, many characteristics of B-RAN remain unclear and hard to characterize. In this study, we develop an analytical framework to model B-RAN and provide some basic fundamental analysis. Starting from block generation, we establish a queuing model based on a time-homogeneous Markov chain. From the queuing model, we evaluate the performance of B-RAN with respect to latency and security considerations. We uncover a more comprehensive picture of the achievable performance of B-RAN by connecting latency and security. At last, we present experimental results via an innovative prototype and validate the proposed model.

Practical Modeling and Analysis of Blockchain Radio Access Network

We present a blockchain radio access network (B-RAN) as an advanced wireless access paradigm. The proposed B-RAN unites massive trustless subnetworks to form a large-scale trustworthy cooperative network by leveraging the blockchain principle. We introduce the economic concept of network effects with respect to the benefit of a growing B-RAN. We show that B-RAN can create and capture values by connecting multilateral groups and constructing a multi-sided platform (MSP). To establish multi-fold trust among distinct groups for deep integrations and healthy interactions, we divide functions of B-RAN into six layers within a hierarchical architecture to build trust from the ground up, and provide a number of key enabling technologies to overcome major obstacles in B-RAN. More importantly, we assess the performance of B-RAN using our unique in-house prototype through three representative case studies.

Blockchain Radio Access Network Beyond 5G

The explosion of Internet of Things (IoT) applications makes the existing network structure insufficient because it is split by multiple non-cooperative operators, does not scale with the future development of IoT, and calls for novel networking concepts and protocols. The need for multi-operator IoT paradigms poses some unprecedented challenges, including trust considerations. To enable a multi-operator network without shared authentication, we propose a trustworthy grant-free IoT access protocol named Hash Access by leveraging a blockchain radio access network (B-RAN) architecture. B-RAN re-organizes multiple individual radio access networks into a joint multi-operator network based on a blockchain. B-RAN can establish trust among initially trustless operators and efficiently utilize resources across networks, matching and creating values for multiple participants. Furthermore, to mitigate the loss of network efficiency caused by selfish behavior among untrustworthy IoT devices, the proposed protocol can induce IoT devices to follow an access rule and control their data traffic. The proposed framework unifies the IoT access and the underlying B-RAN to reduce confirmation delays in traditional blockchains significantly. Numerical experiments illustrate the performance edge for the B-RAN-enabled Hash Access.

Hash Access: Trustworthy Grant-Free IoT Access Enabled by Blockchain Radio Access Networks

The concept of blockchain radio access network (B-RAN) was proposed to integrate cross-network resources including spectra and infrastructures to meet the explosive growth of diverse connectivity needs. In this work, we consider the prototype design of B-RAN and address the issues arising in its implementation. To reduce the access delay, we develop a fast smart contract deployment (FSCD) for B-RAN. Also, we propose the concept of digitized spectrum assets (DSA) in B-RAN for efficient spectrum sharing and management. We further summarize and demonstrate the B-RAN prototype enhanced by the newly introduced FSCD and DSA, along with the overall workflow. We apply comprehensive simulations based on an inhouse experimental platform to illustrate the effectiveness of the proposed B-RAN prototype.

Yuwei Le

Papers

Blockchain-enabled wireless communications: a new paradigm towards 6G.

Practical Modeling and Analysis of Blockchain Radio Access Network

Blockchain Radio Access Network Beyond 5G

Hash Access: Trustworthy Grant-Free IoT Access Enabled by Blockchain Radio Access Networks

Prototype Design and Test of Blockchain Radio Access Network