The vision of next generation 5G wireless communications lies in providing very high data rates (typically of Gbps order), extremely low latency, manifold increase in base station capacity, and significant improvement in users’ perceived quality of service (QoS), compared to current 4G LTE networks. Ever increasing proliferation of smart devices, introduction of new emerging multimedia applications, together with an exponential rise in wireless data (multimedia) demand and usage is already creating a significant burden on existing cellular networks. 5G wireless systems, with improved data rates, capacity, latency, and QoS are expected to be the panacea of most of the current cellular networks’ problems. In this survey, we make an exhaustive review of wireless evolution toward 5G networks. We first discuss the new architectural changes associated with the radio access network (RAN) design, including air interfaces, smart antennas, cloud and heterogeneous RAN. Subsequently, we make an in-depth survey of underlying novel mm-wave physical layer technologies, encompassing new channel model estimation, directional antenna design, beamforming algorithms, and massive MIMO technologies. Next, the details of MAC layer protocols and multiplexing schemes needed to efficiently support this new physical layer are discussed. We also look into the killer applications, considered as the major driving force behind 5G. In order to understand the improved user experience, we provide highlights of new QoS, QoE, and SON features associated with the 5G evolution. For alleviating the increased network energy consumption and operating expenditure, we make a detail review on energy awareness and cost efficiency. As understanding the current status of 5G implementation is important for its eventual commercialization, we also discuss relevant field trials, drive tests, and simulation experiments. Finally, we point out major existing research issues and identify possible future research directions.

Next Generation 5G Wireless Networks: A Comprehensive Survey

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 orthogonal frequency-division multiple access-based random access approach as well as novel spatial frequency reuse techniques. In addition, this tutorial will highlight selected significant improvements (including physical layer enhancements, multi-user multiple input multiple output extensions, power saving advances, and so on) which make this standard a very significant step forward with respect to its predecessor 802.11ac.

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A Tutorial on IEEE 802.11ax High Efficiency WLANs

5G roadmap

To enable large-scale and ubiquitous automotive network access, traditional vehicle-to-everything (V2X) technologies are evolving to the Internet of Vehicles (IoV) for increasing demands on emerging advanced vehicular applications, such as intelligent transportation systems (ITS) and autonomous vehicles. In recent years, IoV technologies have been developed and achieved significant progress. However, it is still unclear what is the evolution path and what are the challenges and opportunities brought by IoV. For the aforementioned considerations, this article provides a thorough survey on the historical process and status quo of V2X technologies, as well as demonstration of emerging technology developing directions toward IoV. We first review the early stage when the dedicated short-range communications (DSRC) was issued as an important initial beginning and compared the cellular V2X with IEEE 802.11 V2X communications in terms of both the pros and cons. In addition, considering the advent of big data and cloud-edge regime, we highlight the key technical challenges and pinpoint the opportunities toward the big data-driven IoV and cloud-based IoV, respectively. We believe our comprehensive survey on evolutionary V2X technologies toward IoV can provide beneficial insights and inspirations for both academia and the IoV industry.

Evolutionary V2X Technologies Toward the Internet of Vehicles: Challenges and Opportunities

With the proliferation of connected devices and emerging data-hungry applications, the volume of mobile data traffic is predicted to have a 1000-fold growth by the year 2020. To address the challenge of this data explosion, industry and academia have initiated research and development of 5G wireless networks, which are envisaged to cater to the massive data traffic volume, while providing ubiquitous connectivity and supporting diverse applications with different quality of service (QoS) requirements. To support the expected massive growth of mobile data, a large number of small cells are expected to be deployed indoors and outdoors, giving rise to heterogeneous networks (HetNets), which are considered to be the key path toward 5G. With such large-scale HetNets, network operators face many serious challenges in terms of operation and management, costeffective small cell deployment, and intercell interference mitigation. To deal with those issues, a cloud based platform is introduced, aiming to simplify the deployment, operation and management, and facilitate round-the-clock optimization of the network, to pave the way for the development of 5G. Two case studies are provided to illustrate the benefits of the cloud based architecture. Finally, the related standardization activities are provided and some research topics essential for a successful development of 5G are discussed.

Cloud assisted HetNets toward 5G wireless networks

The emerging paradigm of the Internet of Everything, along with the increasing demand of Internet services everywhere, results in a remarkable and continuous growth of the global Internet traffic. As a cost-effective Internet access solution, WiFi networks currently generate a major portion of the global Internet traffic. Furthermore, the number of WiFi public hotspots worldwide is expected to increase by more than sevenfold by 2018. To face this huge increase in the number of densely deployed WiFi networks, and the massive amount of data to be supported by these networks in indoor and outdoor environments, it is necessary to improve the current WiFi standard and define specifications for high efficiency wireless local area networks (HEWs). This paper presents potential techniques that can be applied for HEWs, in order to achieve the required performance in dense HEW deployment scenarios, as expected in the near future. The HEW solutions under consideration includes physical layer techniques, medium access control layer strategies, spatial frequency reuse schemes, and power saving mechanisms. To accurately assess a newly proposed HEW scheme, we discuss suitable evaluation methodologies, by defining simulation scenarios that represent future HEW usage models, performance metrics that reflect HEW user experience, traffic models for dominant HEW applications, and channel models for indoor and outdoor HEW deployments. Finally, we highlight open issues for future HEW research and development.

A Survey on High Efficiency Wireless Local Area Networks: Next Generation WiFi

In this paper, energy efficient uplink communications are investigated for battery-constrained mobile terminals (MTs) with service quality requirements and multi-homing capabilities. A heterogeneous wireless medium is considered, where MTs communicate with base stations (BSs) and access points (APs) of different networks with overlapped coverage. Different from the existing works, we develop a quality of service (QoS)-based optimization framework for joint uplink bandwidth and power allocation to maximize energy efficiency for a set of MTs with multi-homing capabilities. The proposed framework is implemented in a decentralized architecture, through coordination among BSs/APs of different networks and MTs, which is a desirable feature when different networks are operated by different service providers. A suboptimal framework is presented with a reduced computational complexity as compared with the optimal framework. Simulation results demonstrate the improved performance of both the optimal and suboptimal frameworks over a state-of-the-art benchmark.

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Uplink Decentralized Joint Bandwidth and Power Allocation for Energy-Efficient Operation in a Heterogeneous Wireless Medium

To satisfy the ever increasing wireless service demand, it is effective to form a converged network by utilizing interworking mechanisms, such that the resources of heterogeneous wireless networks can be allocated in a coordinated and efficient manner. Despite the potential advantages of a converged network, its performance needs further improvement, especially at cell edges and rural areas where only one network is available. In this article, we investigate how to leverage device-to-device, D2D, communication to further improve the performance of a converged network which consists of an LTE-A cellular network and IEEE 802.11n WLANs. Three main technical challenges that complicate resource allocation are identified: allocation of resources capturing diverse radio access technologies of the networks, selection of users’ communication modes for multiple networks to maximize hop and reuse gains, and interference management. To address these challenges, we propose a resource allocation scheme that performs mode selection, allocation of WLAN resources, and allocation of LTE-A network resources in three different timescales. The resource allocation scheme is semi-distributedly implemented in the underlying converged D2D communication network, and the achievable performance improvements are demonstrated via simulation results.

Device-to-device communication underlaying converged heterogeneous networks

This paper investigates energy efficient uplink communications for battery-constrained mobile terminals (MTs). We consider a heterogeneous wireless medium where MTs communicate with base stations (BSs) and access points (APs) of different networks with overlapped coverage. Unlike the existing research, we develop a joint bandwidth and power allocation framework that maximizes energy efficiency for a set of MTs, in different service areas, with best effort service and multi-homing capabilities. The problem formulation captures the heterogeneity of the medium, in terms of different service areas, channel conditions, available resources at BSs/APs of different networks, and different available maximum power at the MTs. In addition, the framework is implemented in a decentralized manner which is desirable in a case that different networks are operated by different service providers. Simulation results are presented to demonstrate the performance of the proposed framework.

Amila Tharaperiya Gamage

Papers

Cloud assisted HetNets toward 5G wireless networks

A Survey on High Efficiency Wireless Local Area Networks: Next Generation WiFi

Uplink Decentralized Joint Bandwidth and Power Allocation for Energy-Efficient Operation in a Heterogeneous Wireless Medium

Device-to-device communication underlaying converged heterogeneous networks

Energy efficient uplink resource allocation in a heterogeneous wireless medium