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Wi-Fi faces the new wireless ecosystem: a critical review
Abstract
Over the last three decades, we have become more dependent on wireless connectivity to access services and applications from nearly anywhere. The overstated emergence of the all-encompassing fifth generation (5G) of mobile systems begs the question of the future of the new generation of IEEE 802.11 (Wi-Fi) solutions. However, Wi-Fi has certain advantages compared to cellular systems in different ways: (i) a fast-paced standardization process; (ii) a diverse, agile, and highly competitive manufacturer base; and (iii) a broad base of early adopters for both office and house wireless networks. In addition, the rise of enabling technologies, such as software-defined wireless networks, may allow more robust and reliable Wi-Fi networks to bridge gaps in Wi-Fi technology to reach several vertical sectors. This review provides a technical analysis of the relationship between broadband wireless and Wi-Fi technologies. Wi-Fi has taken decisive steps with the evolution of several standards, and there is already evidence that Wi-Fi may partially (or completely) fulfill 5G’s strict service requirements. Next, we discussed the Wi-Fi and 5G convergence, which allow more control over user experiences and provide better service. This review concludes with an analysis of open challenges in the convergence of 5G and Wi-Fi systems. We conclude that Wi-Fi technology has and will continue to have a decisive role as an access technology in the new ecosystem of wireless networks.
... Considering 2030 as a landmark for sustainable mobility, B5G/6G networks need to pave the way for safe, affordable, accessible, and sustainable transport systems and improve road safety. Recently, the large volumes of data sensed in transportation scenarios, primarily driven by the use of computer vision applications for detection, classification, and tracking of transportation system agents, have established technical requirements for which two main solutions of radio access technology have been adopted: B5G communications and Wi-Fi [134]. ...
... On the other hand, Wi-Fi has been part of the planning in the automotive industry for some time [134]. Wireless Access in Vehicular Environments (WAVE) is defined in the IEEE 802.11p amendment to support Intelligent Transportation System (ITS) applications. ...
Intelligent transportation systems (ITS) have been attracting the attention of industry and academia alike for addressing issues raised by the 2030 agenda for sustainable development goals (SDG) approved by the United Nations. However, the diversity and dynamics of present-day transportation scenarios are already very complex, turning the management of ITS into a virtually impossible task for conventional traffic control centers. Recently, the digital twin (DT) paradigm has been presented as a modern architectural concept to tackle complex problems, such as the ones faced by ITS. This survey aims to provide a piece-wise approach to introducing DTs into sustainable ITS by addressing the following cornerstone aspects: i) Why should one consider DTs in ITS applications? ii) What can DTs represent from ITS’ new physical environments? And iii) How can one use DTs to address ITS SDG related to efficiency, safety, and ecology? Our methodological approach for surveying the literature addresses these questions by categorizing contributions and discriminating their ITS elements and agents against the SDG they addressed. Thus, this survey provides an in-depth and contextualized overview of the challenges when approaching ITS through DTs, including scenarios involving autonomous and connected vehicles, ITS infrastructure, and traffic agents’ behavior. Moreover, we propose a functional reference framework for developing DTs of ITS. Finally, we also offer research challenges regarding standardization, connectivity infrastructure, security and privacy aspects, and business management for properly developing DTs for sustainable ITS.
... The proliferation of smartphones, tablets, laptops, and IoT devices has further increased reliance on Wi-Fi networks. Wi-Fi provides a fast connection to the internet without the need for cables or wires [8], [9]. The technology is built on three fundamental components: radio waves, transceivers, and the data transfer path, with radio frequency (RF) signals playing a central role alongside intermediate network modules. ...
Public Wi-Fi networks are integral to modern connectivity, offering users convenient internet access in public spaces such as cafes, airports, and libraries. However, their open nature and lack of robust security mechanisms make them vulnerable to a myriad of cyber threats, posing significant risks to user data, privacy, and overall network integrity. This paper explores the key challenges in securing public Wi-Fi networks, including issues such as unencrypted communication, rogue access points, man-in-the-middle attacks, and user authentication vulnerabilities. Additionally, the impact of user behavior, the proliferation of insecure IoT devices, and the absence of standardized security practices are examined. While emerging technologies like WPA3, Opportunistic Wireless Encryption (OWE), and AI-driven threat detection offer promising solutions, their adoption faces barriers due to legacy systems, cost constraints, and lack of user awareness. By analyzing these challenges and evaluating current mitigation strategies, this paper aims to highlight the critical need for a multifaceted approach-encompassing advanced technology, policy enforcement, and user education-to enhance the security of public Wi-Fi networks and ensure safer connectivity in the digital age.
... As WiFi APs continue to be deployed in a wide range of applications, it is anticipated that an increasing number of NFV instances will run on these APs [41]- [44]. For example, implementing security functions like firewalls and intrusion detection directly on APs can provide faster threat responses, while deploying content caching applications at the edge can significantly reduce bandwidth consumption and improve user experience by delivering content more quickly. ...
As the number of WiFi devices and their traffic demands continue to rise, the need for a scalable and high-performance wireless infrastructure becomes increasingly essential. Central to this infrastructure are WiFi Access Points (APs), which facilitate packet switching between Ethernet and WiFi interfaces. Despite APs' reliance on the Linux kernel's data plane for packet switching, the detailed operations and complexities of switching packets between Ethernet and WiFi interfaces have not been investigated in existing works. This paper makes the following contributions towards filling this research gap. Through macro and micro-analysis of empirical experiments, our study reveals insights in two distinct categories. Firstly, while the kernel's statistics offer valuable insights into system operations, we identify and discuss potential pitfalls that can severely affect system analysis. For instance, we reveal the implications of device drivers on the meaning and accuracy of the statistics related to packet-switching tasks and processor utilization. Secondly, we analyze the impact of the packet switching path and core configuration on performance and power consumption. Specifically, we identify the differences in Ethernet-to-WiFi and WiFi-to-Ethernet data paths regarding processing components, multi-core utilization, and energy efficiency. We show that the WiFi-to-Ethernet data path leverages better multi-core processing and exhibits lower power consumption.
... Artetxe et al. pointed that even for time-critical activities, such as in closed-loop control systems with sluggish dynamic processes, it's currently that the models are getting scope of use [7]. Nevertheless, with the availability of multiple pertinent technologies, wireless technologies have been undergoing rapid evolution in recent years. ...
URLLC, Ultra-Reliable and Low-Latency Communications, is the most customer-beneficial 5G feature. These technologies will be used in urgent communication, such as mobility coordination and remote robot control. Many networking protocols now use time synchronization to improve communication efficiency, adaptability, and dependability. Automation systems, real-time healthcare, autonomous driving, and networked arts-based professional film use physical networks. Applications are one of the most amazing and unimaginable capabilities of high-reliable communication. IEEE 802. TSN technology and standards provide strong, reliable, real-time, deterministic communications with low latency and no bottlenecks. IEEE 802. The best and most adaptable Wi-Fi is 11ax. IEEE 802. The 11ax focuses on smooth wireless provision for regular devices, unlike Wi-Fi, which handles data transfer rates. The research focuses on and defends URLLC and Wi-Fi 6 parts where IEEE 802. 11ax can be most effectively incorporated. Then, the communication channel's effectiveness and relevance for future hardware use are assessed (IEEE 802). Wi-Fi 6 and 802. 11ac, its predecessor, complete the next dimension. This aim shows the growing importance of communication-based technologies in the information system. We try to make the system more helpful, effective, and fast. This research aims to determine if modern models' emergent technologies fill a big and stable gap. The report clearly reveals that funds were wisely spent and capital was used efficiently, demonstrating the wisdom of these measures.
... However, currently exists an ecosystem of 5G networks based on an expensive infrastructure that limits the introduction of 5G and its related use cases. This limitation is produced by the excessive cost of the current 5G components comparing to its performance which may be faced with other technologies such as WiFi-6 mainly in terms of speed and latency [1]. ...
Li-Fi technology uses visible light communication for data transmission and has the potential to transform wireless communication. The benefits offered by this technology have the potential to transform wireless communication, many industries, and improve communication in both indoor and outdoor environment. It provides significantly faster speeds and has better security standards compared to Wi-Fi. In this chapter, the authors discuss significant developments in Li-Fi, such as compatibility with 5G networks, support of IoT, security and privacy concerns. They have also presented an in-depth analysis of Li-Fi, including its potential benefits and drawbacks, as well as its range limitations, interoperability issues, and cost implications. This study aims to provide a comprehensive overview and contribute to the understanding and advancement of the technology by examining the basic ideas, technological advances, and issues of Li-Fi. The goal of this chapter is to improve the understanding and ability to use Li-Fi as a next generation technology in wireless communications.
Vehicular Ad-Hoc Networks (VANETs) is a type of mobile ad hoc network (MANET) specifically designed for communication among vehicles on the road. VANETs enable vehicles to communicate with each other and with roadside infrastructure, forming a dynamic and self-organizing network without the need for a fixed communication infrastructure. Security concerns in VANETs encompass a range of threats, including Authentication and Authorization attacks, Sybil attacks, Denial-of-Service incidents, Location spoofing, and Eavesdropping. Privacy, on the other hand, is a paramount concern in VANETs due to the sensitive nature of location-based data, Identity Disclosure, and user consent Control. The paper emphasizes the necessity for robust security mechanisms and outlines specific requirements for safeguarding VANETs. Proposed mitigation measures, including cryptographic techniques and authentication mechanisms, are critically assessed for their effectiveness and feasibility. The findings provide a comprehensive understanding of the complexities surrounding privacy and security in VANETs, contributing valuable insights for the development of resilient and privacy-preserving vehicular communication systems.
Many emerging applications require a higher level of flexibility, modularity, and efficiency but are dependent on advancements in communication infrastructure and distributed computing. Time-sensitive networking (TSN) standards aim at providing vendor agnostic, reliable, and deterministic communications over the Ethernet, but lack in flexibility and modularity provisions. In this context wireless communication systems are preferred given the obvious benefits in terms of increased flexibility, reduced deployment & maintenance costs, and inherent mobility support. However, the stochastic nature of the wireless medium poses several challenges in achieving these benefits. In this paper we comprehensively analyze the recent standardization efforts and developments in IEEE 802.11 and 5G to enable low-latency, deterministic communications and present the current status of their integration with wired TSN. Then, we present a set of use cases that may be enabled by wireless TSN including industrial automation, automotive, or audiovisual applications.
A short time after the official launch of WiFi 6, IEEE 802.11 working groups along with the WiFi Alliance are already designing its successor in the wireless local area network (WLAN) ecosystem: WiFi 7. With the IEEE 802.11be amendment as one of its main constituent parts, future WiFi 7 aims to include time-sensitive networking (TSN) capabilities to support low latency and ultra-reliability in license-exempt spectrum bands, enabling many new Internet of Things scenarios. This article first introduces the key features of IEEE 802.11be, which are then used as the basis to discuss how TSN functionalities could be implemented in WiFi 7. Finally, the benefits and requirements of the most representative Internet of Things low-latency use cases for WiFi 7 are reviewed: multimedia, healthcare, industrial, and transport.
In recent years, significant attention has been directed toward the fifth generation of wireless broadband connectivity known as ‘5G’, currently being deployed by Mobile Network Operators. Surprisingly, there has been considerably less attention paid to ‘Wi-Fi 6’, the new IEEE 802.1ax standard in the family of Wireless Local Area Network technologies with features targeting private, edge-networks. This paper revisits the suitability of cellular and Wi-Fi in delivering high-speed wireless Internet connectivity. Both technologies aspire to deliver significantly enhanced performance, enabling each to deliver much faster wireless broadband connectivity, and provide further support for the Internet of Things and Machine-to-Machine communications, positioning the two technologies as technical substitutes in many usage scenarios. We conclude that both are likely to play important roles in the future, and simultaneously serve as competitors and complements. We anticipate that 5G will remain the preferred technology for wide-area coverage, while Wi-Fi 6 will remain the preferred technology for indoor use, thanks to its much lower deployment costs. However, the traditional boundaries that differentiated earlier generations of cellular and Wi-Fi are blurring. Proponents of one technology may argue for the benefits of their chosen technology displacing the other, requesting regulatory policies that would serve to tilt the marketplace in their favour. We believe such efforts need to be resisted, and that both technologies have important roles to play in the marketplace, based on the needs of heterogeneous use cases. Both technologies should contribute to achieving the goal of providing affordable, reliable, and ubiquitously available high-capacity wireless broadband connectivity.
The rapid proliferation of user devices with access to mobile broadband has been a challenge from both the operation and deployment points of view. With the incorporation of new services with high demand for bandwidth such as video in 4K, it has been deemed necessary to expand the existing capacity by including new bands, among which the unlicensed 5-GHz band is a very promising candidate. The operation of future 3GPP (Third Generation Partnership Project) mobile network standards deployments in this band implies the coexistence with other technologies such as WiFi, which is widespread. In this context, the provision of Quality of Service (QoS) or Quality of Experience (QoE) becomes an essential asset and is a challenge that has yet to be overcome. In this sense, 3GPP has proposed a traffic prioritization method based on the Listen Before Talk access parameters, defining a series of priorities. However, it does not specify how to make use of them, and even less so in potentially conflicting situations. This paper assesses the end-to-end performance of downlink unlicensed channel priorities in dense scenarios via implementing a novel simulation setup in terms of both multi-service performance and coexistence.
The ever-increasing demand for unlicensed spectrum has prompted regulators in the US and Europe to consider opening up the 6 GHz bands for unlicensed access. These bands will open up 1.2 GHz of additional spectrum for unlicensed radio access technologies (RATs), such as Wi-Fi and 5G New Radio Unlicensed (NR-U), in the US and if permitted, 500 MHz of additional spectrum in Europe. The abundance of spectrum in these bands creates new opportunities for the design of mechanisms and features that can support the emerging bandwidth-intensive and latency-sensitive applications. However, coexistence of unlicensed devices both with the bands’ incumbent users and across different unlicensed RATs present significant challenges. In this paper, we provide a comprehensive survey of the existing literature on various issues surrounding the operations of unlicensed RATs in the 6 GHz bands. In particular, we discuss how key features in next-generation Wi-Fi are being designed to leverage these additional unlicensed bands. We also shed light on the foreseeable challenges that designers of unlicensed RATs might face in the near future. Our survey encompasses key research papers, contributions submitted to standardization bodies and regulatory agencies, and documents presented at various other venues. Finally, we highlight a few key research problems that are likely to arise due to unlicensed operations in the 6 GHz bands. Tackling these research challenges effectively will be critical in ensuring that the new unlicensed bands are efficiently utilized while guaranteeing the interference-free operation of the bands’ incumbent users.
Featuring a long operation time to avoid frequent battery replacements, highly energy-efficient radios have shown their pivotal functions for low-power and battery-driven devices in supporting manifold Internet-of-Things (IoT) services. To this end, prolific systems for highly energy-efficient radios have been widely deployed, but they impose a critical challenge of sacrificed data rates to preclude the applications that both require high energy efficiency and high data rates. Recently, this challenge has driven the concept of equipping two radio-chains on a low-power device, known as the
primary connectivity radio
(PCR) and
companion connectivity radio
(CCR). The PCR supports high data rate transmissions, and switches to the sleeping mode when no data should be received. In this case, the CCR stays awake to monitor traffic, and wakes up the PCR when data requiring to be received arrives. However, to practice such a concept, sophisticated operations in the physical (PHY) layer and medium access control (MAC) layers are required. Consequently, the IEEE 802.11 Task Group “ba” (TGba) has been formed to launch the normative works since 2017. In the normative development, the most challenging issue lies in the design of a new frame structure especially the preamble sequence, by which the CCR in a station (STA) can efficiently synchronize with an access point (AP) and the PCR can be promptly waken up when an AP wishes to transmit data to an STA. To comprehend such a crucial foundation for the next generation low-power IoT devices, this paper provides comprehensive knowledge of state-of-the-art PHY/MAC operations of IEEE 802.11ba. Most importantly, a preamble sequence design for synchronization is further proposed for the new frames supported in IEEE 802.11ba. Through comprehensively evaluating the performance of different designs (in terms of data rate configuration and synchronization sequences), we justify the outstanding performance of the proposed design in terms of the synchronization error rate and packet error rate, to satisfy the urgent demands in the normative works of IEEE 802.11ba.
While customers rivet their eyes on Wi-Fi 6, in the bowels of the IEEE 802.11 Working Group that creates Wi-Fi standards, the next generationWi-Fi is being developed. At the very first sight, the new IEEE 802.11be amendment to the Wi-Fi standard is nothing but scaled 11ax with doubled bandwidth and the increased number of spatial streams, which together provide data rates as high as 40 Gbps. A bit deeper dive into the 802.11 activities reveals that 11be will support real-time applications. In reality, 11be introduces many more revolutionary changes to Wi-Fi, which will form a basement for further Wi-Fi evolution. Although by now (May 2020), the development process is at the very early phase without any draft specification, the analysis of the discussion in the 802.11 Working Group gives insights into the main innovations of 11be. In addition to the ones above, they include native multi-link operation, channel sounding optimization that opens the door for massive MIMO, advanced PHY and MAC techniques, the cooperation of various access points. The paper analyzes hundreds of features proposed for the new technology, focusing on the open problems that can be solved by the researchers who want to contribute to the development of 802.11be.
A software-defined networking (SDN) architecture is capable of integrating all radio frequency and optical wireless small cell networks (e.g. fifth generation (5G) , long-term evolution (LTE) femtocell, wireless fidelity (WiFi), light fidelity (LiFi)) in one network domain. This paper considers an SDN-enabled heterogeneous network (HetNet) comprised of LiFi, LTE femtocell and WiFi access points (APs). The states of this HetNet topology and wireless resources are maintained in the network control plane, which can support the development of intelligent service provisioning and efficient data communications in x generation (x G) wireless networks. The SDN applications use the network state to provide services in the data plane. However, when the state of network and wireless resources constantly changes, the SDN applications cannot provide reliable and guaranteed services to the wireless user equipments. This paper develops a queuing theoretic framework, which provides a performance evaluation for the SDN-enabled HetNet and applications convergence. A traffic engineering (TE) scheme is developed to support dynamic agnostic downlink flows routing to APs and differentiated granular services across the HetNet. Network and user centric policies are developed to make applications aware of network resource availability on the northbound and southbound interfaces of an SDN controller. Numerical models are introduced to study the impact of the computation and communication resources of northbound and southbound interfaces on the SDN-enabled HetNet scalability and the quality-of-service (QoS) guarantee of applications. Also, simulation scenarios are conducted to evaluate the performance of the TE scheme in provisioning effective and reliable services for subscribers.
Fifth-generation (5G) and beyond networks are envisioned to provide multi-services with diverse specifications. Network slicing is identified as a key enabling technology to enable 5G networks with multi-services. Network slicing allows a transition from a network-as-an-infrastructure setup to a network-as-a-service to enable numerous 5G smart services with diverse requirements. Although several surveys and tutorials have discussed network slicing in detail, there is no comprehensive study discussing the taxonomy and requirements of network slicing. In this paper, we present and investigate key recent advances of network slicing towards enabling several Internet of Things (IoT) smart applications. A taxonomy is devised for network slicing using different parameters: key design principles, enablers, slicing resources levels, service function chaining schemes, physical infrastructures, and security. Furthermore, we discuss key requirements for network slicing to enable smart services. Finally, we present several open research challenges along with possible guidelines for network slicing.
Wireless Networks have become ubiquitous to support the growing demand from mobile users, and other devices, like in the Internet of Things (IoT). This article proposes a Software-Defined Wireless Networking architecture specialized in 802.11 Wireless LANs, called Ethanol, which provides a more fine-grained control. Ethanol is the first wireless SDN architecture that extends the control to the user devices. Further, Ethanol allows intelligent white-box control with finer grain than the state of the art, since it is optimized for WiFi. The proposed architecture is evaluated on a prototype over three use cases. Ethanol can be deployed in any Access Point (AP) running embedded Linux, since it has a negligible overhead — up to 1% in memory and 0.1% in CPU usage. Our results show that Ethanol dynamically alter the throughput of an application up to 3x during a prioritization period, returning bandwidth to other applications outside this period. Only by controlling the best time to perform the handover, our results show about 45% improvement over the traditional signal-based handover process.
Ultra-reliable communication enables various advance use cases such as autonomous driving and safety critical applications. However, state of the art vehicular communication technologies such as IEEE 802.11p and LTE-V2V cannot meet the requirements. Therefore, the next generation of these technologies are being developed to enhance vehicular support for ultra-reliable use cases. In this paper, the reliability of these upcoming vehicular communication technologies i.e.IEEE 802.11bd and NR-V2X is analyzed. Even though physical layer standardizations are not yet available, candidate settings are used for investigations. We use Monte Carlo based simulations to analyze the physical layer performance of these technologies in multiple V2V scenarios. High Doppler shift in V2V scenarios, is one of the main challenge to realize ultra-reliable communication. It is shown that NR-V2X can be expected to outperform IEEE 802.11bd in terms of reliability due to better handling of Doppler shifts.In case of IEEE 802.11bd, high Doppler shifts cause packet errors even at high signal-to-noise ratio (SNR). Therefore,different measures to improve the performance of IEEE 802.11bd under high Doppler are discussed and evaluated.
With the rising interest in autonomous vehicles, developing radio access technologies (RATs) that enable reliable and low latency vehicular communications has become of paramount importance. Dedicated Short Range Communications (DSRC) and Cellular V2X (C-V2X) are two present-day technologies that are capable of supporting day-1 vehicular applications. However, these RATs fall short of supporting communication requirements of many advanced vehicular applications, which are believed to be critical in enabling fully autonomous vehicles. Both DSRC and C-V2X are undergoing extensive enhancements in order to support advanced vehicular applications that are characterized by high reliability, low latency, and high throughput requirements. These RAT evolutions—IEEE 802.11bd for DSRC and NR V2X for C-V2X—can supplement today’s vehicular sensors in enabling autonomous driving. In this paper, we survey the latest developments in the standardization of 802.11bd and NR V2X. We begin with a brief description of the two presentday vehicular RATs. In doing so, we highlight their inability to guarantee the quality of service requirements of many advanced vehicular applications. We then look at the two RAT evolutions, i.e., IEEE 802.11bd and NR V2X and outline their objectives, describe their salient features and provide an in-depth description of key mechanisms that enable these features. While both, IEEE 802.11bd and NR V2X, are in their initial stages of development, we shed light on their preliminary performance projections and compare and contrast the two evolutionary RATs with their respective predecessors.
Fifth generation (5G) cellular systems are expected to orchestrate a variety of air interfaces. In this heterogenous setting 4G LTE systems will remain of special importance providing service over relatively large area not covered with 3GPP New Radio technology. However, the scarcity of radio resources below 6 GHz as well as constantly increasing user traffic demands call for efficient offloading strategy from LTE network. In this paper, we consider and compare two LTE session offloading strategies including LAA and WiFi offloading. Although by design, the LAA system supports quality-of-service (QoS) guarantees in terms of minimum throughput, the assured performance might still be violated by resource reallocations when satisfying the compulsory fairness criteria. To assess and compare performance of these schemes we develop an analytical framework that takes into account specifics of duty-cycle schedule-based LAA system with CAC, resource reallocation mechanism and realistic elastic traffic nature. As a special case of the developed framework we also address offloading of QoS-aware LTE sessions into conventional WiFi. Our numerical results indicate that WiFi offloading is characterized by a significantly greater number of offloaded sessions. However, this advantage comes at the expense of severe performance degradation in terms of minimum throughput guarantees. Implementing connection admission control procedures, LAA efficiently addresses this problem. We conclude that WiFi offloading of QoS-aware LTE sessions can be used in light traffic conditions only. On the other hand, offloading to the schedule-based LAA system allows to preserve QoS over a wide range of arrival traffic statistics.
We are on the brink of a new era for the wireless telecommunications, an era that will change the way that business is done. The fifth generation (5G) systems will be the first realization in this new digital era where various networks will be interconnected forming a unified system. With support for higher capacity as well as low-delay and machine-type communication services, the 5G networks will significantly improve performance over the current fourth generation (4G) systems and will also offer seamless connectivity to numerous devices by integrating different technologies, intelligence, and flexibility. In addition to ongoing 5G standardization activities and technologies under consideration in the Third Generation Partnership Project (3GPP), the Institute of Electrical and Electronic Engineers (IEEE) based technologies operating on unlicensed bands, will also be an integral part of a 5G eco-system. Along with the 3GPP-based cellular technology, IEEE standards and technologies are also evolving to keep pace with the user demands and new 5G services. In this article, we provide an overview of the evolution of the cellular and Wi-Fi standards over the last decade with particular focus on Medium Access Control (MAC) and Physical (PHY) layers, and highlight the ongoing activities in both camps driven by the 5G requirements and use-cases.
While celebrating the 21st year since the very first IEEE 802.11 “legacy” 2 Mbit/s wireless Local Area Network standard, the latest Wi-Fi newborn is today reaching the finish line, topping the remarkable speed of 10 Gbit/s. IEEE 802.11ax was launched in May 2014 with the goal of enhancing throughput-per-area in high-density scenarios. The first 802.11ax draft versions, namely D1.0 and D2.0, were released at the end of 2016 and 2017. Focusing on a more mature version D3.0, in this tutorial paper, we help the reader to smoothly enter into the several major 802.11ax breakthroughs, including a brand new OFDMA-based random access approach as well as novel spatial frequency reuse techniques. In addition, this tutorial will highlight selected significant improvements (including PHY enhancements, MU-MIMO extensions, power saving advances, and so on) which make this standard a very significant step forward with respect to its predecessor 802.11ac.
The significant growth in the number of WiFi-enabled devices as well as the increase in the traffic conveyed through wireless local area networks (WLANs) necessitate the adoption of new network control mechanisms. Specifically, dense deployment of access points, client mobility, and emerging QoS demands bring about challenges that cannot be effectively addressed by distributed mechanisms. Recent studies show that software-defined WLANs (SDWLANs) simplify network control, improve QoS provisioning, and lower the deployment cost of new network control mechanisms. In this paper, we present an overview of SDWLAN architectures and provide a qualitative comparison in terms of features such as programmability and virtualization. In addition, we classify and investigate the two important classes of centralized network control mechanisms: (i) association control (AsC) and (ii) channel assignment (ChA). We study the basic ideas employed by these mechanisms, and in particular, we focus on the metrics utilized and the problem formulation techniques proposed. We present a comparison of these mechanisms and identify open research problems.
5G has to fulfill the requirements of ultra-dense, scalable, and customizable networks such as IoT while increasing spectrum and energy efficiency. Given the diversity of envisaged applications and scenarios, one crucial property for 5G New Radio (NR) is flexibility: flexible UL/DL allocation, bandwidths, or scalable transmission time interval, and most importantly operation at different frequency bands. In particular, 5G should exploit the spectral opportunities in the unlicensed spectrum for expanding network capacity when and where needed. However, unlicensed bands pose the challenge of "coexisting networks", which mostly lack the means of communication for negotiation and coordination. This deficiency is further exacerbated by the heterogeneity, massive connectivity, and ubiquity of IoT systems and applications. Therefore, 5G needs to provide mechanisms to coexist and even converge in the unlicensed bands. In that regard, WiFi, as the most prominent wireless technology in the unlicensed bands, is both a key enabler for boosting 5G capacity and competitor of 5G cellular networks for the shared unlicensed spectrum. In this work, we describe spectrum sharing in 5G and present key coexistence solutions, mostly in the context of WiFi. We also highlight the role of machine learning which is envisaged to be critical for reaching coexistence and convergence goals by providing the necessary intelligence and adaptation mechanisms.
The IEEE 802.11ad amendment to the 802.11 standard ratified in 2012 created the first multi-Gb/s Wi-Fi technology by using the large swath of unlicensed spectrum at the mm-Wave band. While enabling multi-Gb/s wireless local communications was a significant achievement, throughput and reliability requirements of new applications, such as augmented reality (AR)/virtual reality (VR) and wireless backhauling, exceed what 802.11ad can offer. For this reason, building upon IEEE 802.11ad, the IEEE 802.11 Task Group ay has recently defined new PHY and MAC specifications that enable 100 Gb/s communications through a number of technical advancements. In this article, we identify and describe the main design elements of IEEE 802.11ay, including MIMO, channel bonding, improved channel access, and enhanced beamforming training. For each of these elements, we discuss how their design is impacted by mm-Wave radio propagation characteristics and present enabling mechanisms defined in IEEE 802.11ay.
IEEE 802.11 wireless LAN is proliferating since the increased trend in the wireless network utilization on mobile devices. Accuracy, fast content delivery, and reliable mobility support are essential features of any network to support the changing trend in a wireless network. However, traditional architectures in wireless LAN (WLANs or WiFi) always endured from challenges such as the provision of consistent mobility, real-time packet flow, and seamless handoff. Generally, most of the WLAN only relies on signal strength for handoff which is not sufficient enough for fair selection of an access point (AP) and therefore causes imperfect performance of the network. We present a novel mobility management scheme for WLANs to deal with the mobility management issues, and load balancing by software-defined network (SDN) and network function virtualization (NFV) technologies. The proposed scheme is based on logical AP (LAP) that keeps a connection with the user/mobile terminal (MT) during handoff triggered by either the user or the SDN controller for seamless mobility. It also involves the current state of each AP in addition to traditional parameters of WLAN. We implemented the proposed scheme on a real testbed in a WLAN environment. The evaluation results authenticate that our proposed scheme provides robust handover without throughput degradation and load imbalance among adjacent APs, and allocates the best AP in the neighboring region. Moreover, our proposed scheme is feasible to implement since it did not require any modification at the mobile terminal.
The trend for dense deployment in future 5G mobile communication networks makes current wired backhaul infeasible owing to the high cost. Millimetre-wave (mm-wave) communication, a promising technique with the capability of providing a multi-gigabit transmission rate, offers a flexible and cost-effective candidate for 5G backhauling. By exploiting highly directional antennas, it becomes practical to cope with explosive traffic demands and to deal with interference problems. Several advancements in physical layer technology, such as hybrid beamforming and full duplexing, bring new challenges and opportunities for mm-wave backhaul. This article introduces a design framework for 5G mm-wave backhaul, including routing, spatial reuse scheduling and physical layer techniques. The associated optimization model, open problems and potential solutions are discussed to fully exploit the throughput gain of the backhaul network. Extensive simulations are conducted to verify the potential benefits of the proposed method for the 5G mm-wave backhaul design.
An unprecedented increase in the mobile data traffic volume has been recently reported due to the extensive use of smartphones, tablets, and laptops. This is a major concern for mobile network operators, who are forced to often operate very close to their capacity limits. Recently, different solutions have been proposed to overcome this problem. The deployment of additional infrastructure, the use of more advanced technologies (LTE), or offloading some traffic through Femtocells and WiFi are some of the solutions. Out of these, WiFi presents some key advantages such as its already widespread deployment and low cost. While benefits to operators have already been documented, it is less clear how much and under what conditions the user gains as well. Additionally, the increasingly heterogeneous deployment of cellular networks (partial 4G coverage, small cells, etc.) further complicates the picture regarding both operator-and user-related performance of data offloading. To this end, in this paper we propose a queueing analytic model that can be used to understand the performance improvements achievable by Wi-Fi-based data offloading, as a function of Wi-Fi availability and performance, user mobility and traffic load, and the coverage ratio and respective rates of different cellular technologies available. We validate our theory against simulations for realistic scenarios and parameters, and provide some initial insights as to the offloading gains expected in practice.
New applications are emerging that bring new and stricter requirements for WiFi. Smart factories, mobile and collaborative robots, and Extended Reality (XR) demand deterministic wireless connectivity with ultra-low latency. This article focuses on the challenges and enhancements supporting Time-Sensitive Networking (TSN) that enable WiFi to support usages that require deterministic operation. The article reviews existing and future time-sensitive applications and their connectivity requirements. It discusses the evolution of the TSN capabilities supported by various WiFi generations, from legacy standards to the latest 802.11ax specification and the ongoing progress in the 802.11be Task Group specific to deterministic operation. The article also discusses the open challenges for next generation WiFi, including ultra-low latency (sub-millisecond) with higher efficiency. The article concludes with a review of the TSN ecosystem activities toward interoperability testing and certification of WiFi TSN and discusses testbed results demonstrating the 802.11ax and 802.11be tools to achieve deterministic operation.
The safety-critical applications of Vehicular Ad Hoc Networks (VANETs) call for wireless communication systems with high reliability and low transmission latency. Recently, a very promising communication system standardized as IEEE 802.11bd was proposed and studied to address the reliability deficiency of IEEE 802.11p based Dedicated Short Range Communications (DSRC) system in the adverse vehicular situations. Seamless evolution of radio access technology from IEEE 802.11p to IEEE 802.11bd have undergone performance improvement evaluations in the physical layer. However, the impact of the enhancements on the network layer and safety services in VANETs remain unknown. In this paper, we conduct analysis of IEEE 802.11bd beyond the physical layer. First, the performance gains of IEEE 802.11bd comparing to IEEE 802.11p in the physical layer are summarized. Then, packet loss rate (PLR) curves as a function of signal-to-noise ratio (SNR) in the physical layer are quantified and connected to the quality of service (QoS) metrics in the MAC layer, while considering the effect of channel access and interference among network nodes. Furthermore, application-level analysis is conducted to identify if the proposed IEEE 802.11bd can meet the QoS requirements of the selected safety applications where IEEE 802.11p previously failed. Finally, constructive conclusions are presented on IEEE 802.11bd’s suitability for VANET critical safety services and future developments.
The increasing number of heterogeneous devices connected to the Internet, together with tight 5G requirements have generated new challenges for designing network infrastructures. Industrial verticals such as automotive, smart city and eHealthcare (among others) need secure, low latency and reliable communications. To meet these stringent requirements, computing resources have to be moved closer to the user, from the core to the edge of the network. In this context, ETSI standardized Multi-Access Edge Computing (MEC). However, due to the cost of resources, MEC provisioning has to be carefully designed and evaluated. This survey firstly overviews standards, with particular emphasis on 5G and virtualization of network functions, then it addresses flexibility of MEC smart resource deployment and its migration capabilities. This survey explores how the MEC is used and how it will enable industrial verticals.
Multi-Access Edge Computing (MEC) will allow implementing low-latency services that have been unfeasible so far. The European Telecommunications Standards Institute (ETSI) and the 3rd Generation Partnership Project (3GPP) are working towards the standardization of MEC in 5G networks and the corresponding solutions for routing user traffic to applications in local area networks. Nevertheless, there are neither practical implementations for dynamically relocating applications from the core to a MEC host nor from one MEC host to another ensuring service continuity. In this paper we propose a solution based on Software-Defined Networking (SDN) to create a new instance of the IP anchor point to dynamically redirect User Equipment (UE) traffic to a new physical location (e.g. an edge infrastructure). We also present a novel approach that leverages SDN to replicate the previous context of the connection in the new instance of the IP anchor point, thus guaranteeing Session and Service Continuity (SSC), and compare it with alternative state replication strategies. This approach can be used to implement edge services in 4G or 5G networks.
This chapter discusses the ongoing work around hybrid access and network convergence, with particular emphasis on recent works on ATSSS in 3GPP. Three main aspects are analyzed: policy enforcement, integration with 5G QoS framework, interaction with underlying multi-path transport protocol. The chapter also provides some preliminary testbed results showing the benefits of ATSSS in the management of multiple accesses analyzing some primary performance indicators such as achievable data rates, link utilization for aggregated traffic, and session setup latency. The chapter also provides some results by considering two examples of realization of ATSSS policies to avoid inefficiency in link utilization and to allow the fulfillment of data rate requirements.
With network slicing, physical networks are partitioned into multiple virtual networks tailored to serve different types of service with their specific requirements. In order to optimize the utilization of network resources for delay-critical applications, we propose a new multi-domain network virtualization framework based on a novel multipath multihop delay model. This framework encompasses a novel hierarchical orchestration mechanism for mapping network slices onto physical resources and a mechanism for dynamic slice resizing. The main idea is to locally redefine the delay requirements on each network domain depending on the conditions in the rest of the network. Delays larger than threshold (debt) are allowed in certain domains if there is a possibility to compensate such excessive delays in other segments of the network that can transmit the messages with less latency (credit). This tradeoff or delay threshold redefinition on different segments of the route is referred to as network latency equalization. For performance comparison, minimum cost routing with latency constraints is used as a baseline. We show that our approach enables significantly better utilization of the network resources measured in the number of slices with the same latency requirements that can be accommodated in the network.
Due to its ubiquitous use, WiFi may play an essentialrole in providing indoor connectivity for the new real-timeservices in several 5G verticals. However, there are still pressingissues to be addressed, requiring new mobility managementschemes to guarantee reliable and low latency communications.In this paper, we propose a novel SDN-NFV based architec-ture with a low cost off-the-shelf WiFi that explores a multi-connectivity scheme at the user devices. In order to demonstratethe feasibility of our approach, we developed a prototype andperformed experiments on seamless handover using: i) an SDN-NFV based packet duplication solution; and ii) a source-routingsolution for end-to-end communication. Results show that theproposed architecture can provide an efficient seamless handover,increasing the likelihood of delivering packets with minimaleffects on latency.
The ever-increasing deployment of new wireless technologies and the demand for mobile services delivery has hampered the efficient and reliable wireless communication. While traditional IEEE 802.11 Wireless Local Area Networks (WLANs) suffer interference from other wireless technologies, their manageability is currently limited. In this context, the overall performance in terms of bitrate, latency, and reliability depends on a number and often dynamically changing aspects where the Medium Access Control (MAC) layer plays a crucial role. Current IEEE 802.11 MAC protocols cannot be programmed fine-grained enough and they cannot manage multiple networks at runtime. In this paper, we propose an approach and an algorithm for on-the-fly End-to-End (E2E) Quality of Service (QoS) slice orchestration and IEEE 802.11 MAC management based on Software-Defined Networking (SDN) principles. We argue that, by performing slice orchestration and IEEE 802.11 MAC management at runtime, it is possible to deliver improved and reliable E2E QoS. To demonstrate the feasibility of our approach, we developed a prototype where our hands-on experiments show that we can reduce the average latency in half while compromising only less than 8% of the average throughput.
Networks are a core element of many industrial and automation systems at present. Often these networks transport time- and safety-critical messages that control physical processes. Thus, timely and guaranteed delivery is an essential property of networks for such critical systems. Over the past decade, a variety of network solutions have evolved to satisfy said properties. However, these solutions are largely incompatible with each other and many system architects are forced to deploy different solutions in parallel due to their different capabilities. IEEE 802.1 Time-Sensitive Networking (TSN) is a standardization group that enhances IEEE networking standards, most prominently Ethernet-based networks, with said properties and has the unique potential to evolve as a cross-industry mainstream networking technology. In this survey paper, we give an overview of TSN in industrial communication and automation systems and discuss specific TSN standards and projects in detail as well as their applicability to various industries.
Wireless networks have become in the last years a key enabling technology for cloud-enabled robots. Among those, the usage of WiFi is a first choice due to its almost ubiquitous use nowadays. However, WiFi suffers from crucial issues like spectrum interference, connectivity losses, long delay for client association and high latency handover. This work proposes a novel architectural split of the WiFi functionalities based on an enhanced software-defined wireless architecture. Cloud-enabled robots scenarios are addressed to derive results showing that the proposed architecture allows uninterrupted communication during handovers, and a quicker failover management.
Upcoming 5G mobile networks are addressing ambitious KPIs not just in terms of capacity and latency, but also in terms of network control and management. In this direction, network management schemes need to evolve to provide the required flexibility, and automated and integrated management of 5G networks. This also applies to the 5G-Crosshaul transport network, which provides an integrated fronthaul and backhaul. Software defined networking and NFV are seen as key enablers for that. This article validates the flexibility, scalability, and recovery capabilities of the 5G-Crosshaul architecture in a testbed distributed geographically. More specifically, the central component of the validation is the hierarchical 5G-XCI, conceived to handle multi-domain multi-technology transport network resources. Its performance is characterized through two experimental case studies. The first one illustrates the automated provisioning of all network resources required to deploy a complete LTE virtual mobile network featuring fronthaul and backhaul configurations. This takes 10.467 s on average for the network under test. The second one exploits the flexibility of the hierarchical XCI to apply local or centralized service recovery in the event of link failure depending on the desired path optimality vs. recovery time trade-off. On average, recovery takes 0.299 s and 6.652 s, respectively. Overall, the proposed solution contributes to attaining the target set for 5G networks of reducing service setup from hours to minutes.
The use of license-exempt bands offers a promising opportunity to additionally enhance operator networks to meet the future traffic demand. The recent specification efforts in 3GPP have resulted in two major aggregation features that enable LTE networks to benefit from unlicensed spectrum via WLAN. In this article, we provide a thorough overview of these features known as, LTE-WLAN aggregation (LWA) and LTE-WLAN radio level integration with IP security tunnel (LWIP). The article presents and motivates the design choices of protocol architectures, procedures, mobility, and security. It also proposes flow control algorithms suitable for both technologies, which aim at the best usage of licensed and unlicensed spectrum. Simulation results show the performance unveiling the potential gains of these features in different load conditions, also in a comparative manner, showing that LWA substantially outperforms LWIP.
Communication networks are undergoing their next evolutionary step towards 5G. The 5G networks are envisioned to provide a flexible, scalable, agile and programmable network platform over which different services with varying requirements can be deployed and managed within strict performance bounds. In order to address these challenges a paradigm shift is taking place in the technologies that drive the networks, and thus their architecture. Innovative concepts and techniques are being developed to power the next generation mobile networks. At the heart of this development lie Network Function Virtualization and Software Defined Networking technologies, which are now recognized as being two of the key technology enablers for realizing 5G networks, and which have introduced a major change in the way network services are deployed and operated. For interested readers that are new to the field of SDN and NFV this paper provides an overview of both these technologies with reference to the 5G networks. Most importantly it describes how the two technologies complement each other and how they are expected to drive the networks of near future.
In order to efficiently support the Machine-to-Machine (M2M) and Internet of Things (IoT) applications, a new amendment for the Wi-Fi standard known as IEEE 802.11ah is introduced. In 802.11ah (or Wi-Fi HaLow), several enhanced MAC features are added in order to provide scalability for a large number of stations, increase the range of operation, while at the same time reduce the energy consumption compared to the existing Wi-Fi standards. In this paper, a Verilog RTL implementation of the new standard is presented. It is suitable for IoT, M2M, V2V (Vehicle-to-Vehicle) applications, and smart grids that require long battery life and long range reliability. Software simulations using Xilinx Vivado are also provided to verify the design. The design is then synthesized using the same tool, and performance, power, and area are reported.
The proliferation of public Wi-Fi hotspots has brought new business potentials for Wi-Fi networks, which carry a significant amount of global mobile data traffic today. In this paper, we propose a novel
Wi-Fi monetization
model for venue owners (VOs) deploying public Wi-Fi hotspots, where the VOs can generate revenue by providing two different Wi-Fi access schemes for mobile users (MUs): 1) the
premium access
, in which MUs directly pay VOs for their Wi-Fi usage, and 2) the
advertising sponsored access
, in which MUs watch advertisements in exchange of the free usage of Wi-Fi. VOs sell their ad spaces to advertisers (ADs) via an ad platform, and share the ADs’ payments with the ad platform. We formulate the economic interactions among the ad platform, VOs, MUs, and ADs as a three-stage Stackelberg game. In Stage I, the ad platform announces its advertising revenue sharing policy. In Stage II, VOs determine the Wi-Fi prices (for MUs) and advertising prices (for ADs). In Stage III, MUs make access choices and ADs purchase advertising spaces. We analyze the sub-game perfect equilibrium (SPE) of the proposed game systematically, and our analysis shows the following useful observations. First, the ad platform’s advertising revenue sharing policy in Stage I will affect only the VOs’ Wi-Fi prices but not the VOs’ advertising prices in Stage II. Second, both the VOs’ Wi-Fi prices and advertising prices are non-decreasing in the advertising concentration level and non-increasing in the MU visiting frequency. Numerical results further show that the VOs are capable of generating large revenues through mainly providing one type of Wi-Fi access (the premium access or advertising sponsored access), depending on their advertising concentration levels and MU visiting frequencies.
Due to the rapid development of wireless access technologies and smart terminals, mobile data traffic is continuously increasing, which is expected to lead to an explosive growth of data in heterogeneous networks especially cellular networks. It is significant for network operators to expand the capacity of cellular networks to avoid congestion and overload so as to guarantee users' satisfaction. Given that contemporary terminals are capable of both WiFi and cellular networks, WiFi offloading is envisioned as a promising solution to utilize the various benefits of WiFi and cellular networks to migrate traffic from cellular networks to WiFi networks. This paper surveys the state-of-the-art progress in the field of WiFi offloading. After discussing the requirements from the emerging 5G technology regarding the coexistence of WiFi and cellular networks, selecting and switching schemes are presented. The bandwidth and capacity of WiFi networks are usually excellent, whereas the coverage and energy efficiency may be unacceptable. We elaborate on several existing solutions of WiFi offloading schemes and discuss how the parameters of several kinds of heterogeneous networks affect the offloading decision. We also illustrate how multiple networks cooperate in heterogeneous networks in order to balance the offloading performance. We classify current various incentives of WiFi offloading into five categories: 1) capacity; 2) cost; 3) energy; 4) rate; and 5) continuity. Improving the capacity is the basic incentive, which can be further classified in terms of delay techniques. From operators' and users' perspectives, we also investigate various state-of-the-art incentives of WiFi offloading such as minimizing cost, saving energy consumption, and improving rate. Furthermore, WiFi offloading schemes that attempt to enhance continuity to deal with frequent disruption problems are further investigated, especially for vehicular scenarios. Finally, future research directions and challenges for WiFi offloading strategies are presented in various incentives of WiFi offloading.
The components of data architecture include the transactional environment and other operational systems, the ETL function, the data warehouse, an ODS, data marts, and Big Data. Big Data is divided into unstructured repetitive data and unstructured nonrepetitive data. At the heart of data architecture is the notion of the system of record.