Mobile Broadband Systems Research Articles

Mobile Broadband Adoption, Performance Measurements and Methodology: A Review

Mobile broadband (MBB) penetration has deepened globally over the last twenty years. This is largely due to the adoption of smart devices, improved mobile communications network coverage, and the perpetual drive to develop ever faster mobile and wireless communication technologies. However, information on the quality of service (QoS) delivered by MBB operators to the end users remains an issue of concern. This has driven independent researchers and mobile communication industry regulators to develop methodologies for independent and unbiased evaluation of the QoS offered by MBB networks. This paper provides a detailed review of MBB adoption and penetration across several regions of the world. It also includes the existing methodologies for evaluating the performance of MBB systems as experienced by the end user. Specifically, methodologies such as the drive and walk tests, crowd-sourced mobile device-based methods and the software applications they employ, and the dedicated measurement testbeds are reviewed. Based on this, the challenges of adopting each of the methods are discussed in order to make a case for the development of more robust, partially autonomous and scalable MBB measurement platforms for the future.

Ultra-Dense Networks: Taxonomy and Key Performance Indicators

One major influence on the future deployment of cellular networks will be a continuous increase in traffic inside mobile broadband systems. Moreover, traditional macrocell-based mobile communication networks will struggle to keep up with the enormous expansion in the demand for communications services in the future. Densification of networks is required if we are to meet the comprehensive needs for end terminals for a wide range of applications. One of the leading concepts in this competitive environment is the Ultra-Dense Network (UDN) where the access nodes and/or the communication links per unit area are densified, with the aim of improving overall network performance. The location of the UDN nodes meets the criteria for symmetry with a high probability. Ultra-dense cell deployment aims to reduce the physical distance between the transmitter and receiver in order to boost system performance and generally optimize the values of a wide variety of key performance indicators (KPIs). This paper aims to provide a taxonomy of UDNs and specifically of UDN-related KPIs. Initially, we address the complex questions “What is the current understanding of what ultra-dense networks are and what they should be, and how can we measure their performance?” by shedding light on the fundamental characteristics of UDNs.

A review on mmWave based energy efficient RoF system for next generation mobile communication and broadband systems

Abstract In today’s scenario, wireless communication is turning into a decisive and leading backbone to access the worldwide network. Therefore, the usage of mobile phones and broadband is rising staggeringly. To satisfy their expulsive needs, it demands increment in data rates while providing higher bandwidth and utilizing optical fiber in wireless communication, and this becomes a worldwide analysis area. Radio over fiber (RoF) system is taken into account as best solution to fulfill these needs. In RoF system, the radio frequency signal operated at millimeter wave (30–300 GHz) is centralized and processed at control station (CS) and also, the CS upconverts this electrical signal to optical domain. By employing optical fiber link, this signal reaches to base station (BS). Then, the received optical signal converts back to electrical domain at the respective BS. Now BS radiates the electrical signal to corresponding mobile station (MS) in commission with the millimeter wave frequency bands. This RoF system is providing massive bandwidth, facilitating large mobility for RF frequency signals, small loss, fast and cost effective setup, wonderful security, and unlicensed spectrum etc. The RoF system introduces microcells structure for BS cells to boost the frequency reuse and needed capacity. It has benefits in terms of ability to fulfill increasing bandwidth demands to cut back the power consumption and the dimensions of the handset devices. This paper firstly explains the overview of existing wireless mobile communication and broadband systems and then, targets the review of RoF system which will become energy efficient system for next generation mobile communication and future broadband systems. This paper also includes the performance degradation and evaluation parameters. Finally, this paper presents the various research opportunities for its implementation zone.

Radio-frequency chain selection for energy and spectral efficiency maximization in hybrid beamforming under hardware imperfections

The next-generation wireless communications require reduced energy consumption, increased data rates and better signal coverage. The millimetre-wave frequency spectrum above 30 GHz can help fulfil the performance requirements of the next-generation mobile broadband systems. Multiple-input multiple-output technology can provide performance gains to help mitigate the increased path loss experienced at millimetre-wave frequencies compared with microwave bands. Emerging hybrid beamforming architectures can reduce the energy consumption and hardware complexity with the use of fewer radio-frequency (RF) chains. Energy efficiency is identified as a key fifth-generation metric and will have a major impact on the hybrid beamforming system design. In terms of transceiver power consumption, deactivating parts of the beamformer structure to reduce power typically leads to significant loss of spectral efficiency. Our aim is to achieve the highest energy efficiency for the millimetre-wave communications system while mitigating the resulting loss in spectral efficiency. To achieve this, we propose an optimal selection framework which activates specific RF chains that amplify the digitally beamformed signals with the analogue beamforming network. Practical precoding is considered by including the effects of user interference, noise and hardware impairments in the system modelling.

Public Safety Mobile Broadband System: From Shared Network to Logically Dedicated Approach Leveraging 5G Network Slicing

The fourth generation (4G) of the mobile broadband system has widely been considered as the basic technology for the evolution of public safety communications system from legacy narrowband technologies. While 4G provides the essential features for the realization of a public safety network, it has limited flexibility and scalability due to its reliance on hardware-based network functions and its lack of intelligent and automated control capabilities. The fifth-generation (5G) standard introduces the sophisticated concept of network slicing as one of its design principles. The concept enables the creation of logical networks on a common infrastructure with appropriate isolation, resources, and optimized topology to serve a particular use case. In this article, studies on network slicing conceptual framework are summarized. Moreover, the characteristics of a public safety network alongside the current solutions in the 4G system to realize such characteristics are discussed. Furthermore, recent literature that proposes enhancements to 5G system functionalities, which are essential for the efficient and agile management of diverse resources, is examined. In conclusion, substantial research efforts are necessary to improve these functionalities to meet the rigid requirements of public safety use cases in terms of network slice reliability, resiliency, and security.

Enabling Millimeter-Wave 5G Networks for Massive IoT Applications: A Closer Look at the Issues Impacting Millimeter-Waves in Consumer Devices Under the 5G Framework

The Internet of Things (IoT) is one of the most promising technologies of the fifth-generation (5G) mobile broadband system. Data-driven wireless services of 5G systems require unprecedented capacity and availability. In this article, we introduce the potential issues of consumer devices under a unifying 5G framework. We provide a state-of-theart overview with an emphasis on the technical challenges of applying millimeter-wave (mm-wave) technology to support massive IoT applications. Our discussion highlights the challenges and solutions, particularly for communication/computation requirements in consumer devices under the mmwave 5G framework.

A New Centralized Access Control Scheme for D2D-Enabled mmWave Networks

In high-density indoor environments (e.g., airports or malls), it is expected an increase in data demand, in the number of applications having stringent Quality-of-Service requirements, and in the number of services among nearby users, such as video sharing or gaming. In order to satisfy these requirements, we adopt D2D communications, 60 GHz band transmissions, and adaptive beamforming techniques. The symbiosis of these technologies provides notable energy saving, high data rate, and strong interference reduction. Despite these benefits, a major issue is the limited communication range, due to the high path loss. To overcome this issue, we consider a Millimeter-Wave Mobile Broadband (MMB) system, consisting of several Access Points interconnected among themselves through a wireless backhaul network. Based on the specific features of the technologies adopted for the considered MMB system, we aim to improve the transmission efficiency, by exploiting concurrent transmissions. Therefore, we propose a new centralized access control scheme which jointly manages D2D communications and transmissions in the access and the backhaul network. Our control strategy aims to maximize the system throughput, to minimize the end-to-end delay, and to improve the fairness among users, while taking into account to keep the computational load as low as possible. To meet these goals, our proposed access control scheme is composed of a data flow management strategy and a multi-criteria scheduling algorithm based on greedy graph vertex-coloring techniques.

Learning Radio Resource Management in RANs: Framework, Opportunities, and Challenges

In the fifth generation (5G) of mobile broadband systems, radio resource management (RRM) will reach unprecedented levels of complexity. To cope with the ever more sophisticated RRM functionalities and the growing variety of scenarios, while carrying out the prompt decisions required in 5G, this manuscript presents a lean RRM architecture that capitalizes on recent advances in the field of machine learning in combination with the large amount of data readily available in the network from measurements and system observations. The architecture consists of a learner (or a few), which learns RRM policies directly from the data gathered in the network using a single general-purpose learning framework, and a set of distributed actors, which execute RRM policies issued by the learner and repeatedly generate samples of experience. Thus, the complexity of RRM is shifted to the design of the learning framework, while the RRM algorithms derived from this framework are executed in a computationally efficient distributed manner at the radio access nodes. The potential of this approach is verified in a pair of pertinent scenarios, and future directions on applications of machine learning to RRM are discussed. Although we focus on a mobile broadband context, the concepts proposed hereafter extend to any radio access network technology where one can conceive the idea of a central learning unit gathering data from distributed actors.

Key technology and application of millimeter wave communications for 5G: a survey

As mobile communication technology continues to develop, millimeter-wave communication for 5G mobile networks is attracting widespread public attention. Many studies have appeared in the literatures related to millimeter wave mobile broadband communication systems. This paper briefly introduces the development of 5G and millimeter wave communications, analyses several practical designs and implementations of millimeter wave communications for 5G, and proposes some future applications and challenges for 5G.

Analysis and optimization of beamforming methods for high frequency mobile broadband communication system

The explosive growth of wireless data services demands higher capacity of future wireless communication systems to meet this trend. One efficient solution to this problem is to look for more spectral resource. To fully exploit the high potential rates of high frequency in mobile networks, in this paper, we propose a novel beamforming method based on iterative adaptive method, pre-defined selection and compressed sensing, effectively reducing the pilot and feedback overhead of mobile broadband communication with high-frequency band, and suppressing inter-cell interference and extending system coverage.

Performance analysis of cognitive AF relay networks with multiuser switched diversity in Rayleigh fading channels

The multiuser switched diversity (MUSwiD) selection schemes are useful in reducing the required channel estimation load in wireless networks. In this paper, we propose and evaluate the performance of cognitive amplify-and-forward (AF) MUSwiD relay networks where a cognitive user is selected among a set of users for data reception. The selection process is performed such that the end-to-end (e2e) signal-to-noise ratio (SNR) of the selected user satisfies a predetermined switching threshold. Such a user that satisfies this threshold is scheduled instead of the best user to receive its message from the secondary source. In the proposed system, we consider a cognitive source, a cognitive relay, a set of cognitive users, and a primary user. In this paper, an upper bound on the e2e SNR of a user is used in deriving of closed-form approximations for the outage probability and average symbol error probability (ASEP) of the studied system in addition to deriving the ergodic channel capacity. To get more about system insights, the performance is studied at the high SNR regime where approximate expressions for the outage probability, SEP, diversity order, and coding gain are derived. The derived analytical and asymptotic expressions are verified by Monte-Carlo simulations, and some numerical examples are provided to illustrate the effect of some parameters such as number of users and switching threshold on the system performance. Findings illustrate that the diversity order of the studied cognitive AF multiuser switched diversity relaying network is the same as its non-cognitive counterpart. Also, results show that the asymptotic results tightly converge to the exact ones, and the analytical bounds are indeed very tight, validating the accuracy of our approach of analysis. Furthermore, findings illustrate that the proposed MUSwiD user selection schemes are efficient in the range of low SNR values, which makes them attractive options for practical implementation in emerging mobile broadband communication systems. In contrast, these selection schemes are shown to be inefficient in the range of high SNR values where the multiuser diversity gain is noticeably degraded when they are implemented.

Spectrum sharing between communications and ATC radar systems

Increasing demand for wireless communications services within the spectrum bands that are most conducive to operating cellular and mobile broadband systems is aggravating frequency congestion within the electromagnetic spectrum. Primary–secondary spectrum sharing can be exploited to alleviate spectrum congestion by allowing secondary systems to access opportunistically the allotted frequency band of a primary system. In this study, the feasibility of spectrum sharing between air traffic control (ATC) radar and long-term evolution (LTE) wireless communications systems is investigated through waveform-level simulations and link budget analyses. Numerical results show that with moderate frequency and range separation, spectrum sharing between a scanning ATC radar and a single LTE cell in L-band is possible, though both systems are ultimately subject to quantified performance degradations due to the impact each has on the other.

Beyond the Ultra-Dense Barrier: Paradigm Shifts on the Road Beyond 1000x Wireless Capacity

It has become increasingly clear that the current design paradigm for mobile broadband systems is not a scalable and economically feasible way to solve the expected future crunch, in particular in indoor locations with large user densities. Moore's law, for example, state-of-the art signal processing and advanced antenna techniques now being researched, as well as more millimeter wave spectrum, indeed provide more capacity, but are not the answer to the three to four orders of magnitude more capacity at today's cost, that is needed. We argue that solving the engineering problem of providing high data rates alone is not sufficient. Instead, we need to solve the techno-economic problem to find both business models and scalable technical solutions that provide extreme area capacity for a given cost and energy consumption. In this article we will show that achieving very high capacities is indeed feasible in indoor environments. However, to become economically viable, approaches with radically different fundamental cost factors compared to those used in today's cellular systems are needed. To reach very high capacity we must venture beyond the ultra-dense barrier, that is, networks where the number of access points in an area is (considerably) larger than the active number of mobile terminals. In such networks area capacities of more than 1 Gb/s/m2 are perfectly feasible. The problem set encountered in such UDN is very different from conventional cellular systems and their solution requires conceptually new tools. We will address some of the fundamental aspects and performance limits, modeling of propagation, deployment and user traffic, and discuss the techno-economics of various network architectures. Finally we will summarize some of the most significant unsolved research questions in the field.

Spectrum Considerations for 5G Mobile Communication Systems

Increased demand of consumers on services in the mobile environment with high data rate and technologically developed mobile broadband communication systems will require more spectrum to be available in the future. The new technologies require frequencies for their development and usage. One of the main objectives of fifth generation (5G) mobile communication systems, known also as IMT-2020, is to increase the current data rates up to several gigabits per second (Gbit/s) with even more than 10 Gbit/s. One possibility is to consider the use of higher frequencies in order to increase the available bandwidth, which is necessary to achieve such data rates. Main idea of the research is to investigate the available International Mobile Telecommunications (IMT) frequency bands and possible new one – above 6GHz for possible identification worldwide and in Europe for IMT by the 2019 World Radiocommunication Conference (WRC-19). Main characteristics and requirements of IMT-2020 are also provided in this paper.

Coexistence of DTT and Mobile Broadband: A Survey and Guidelines for Field Measurements

This article provides a survey and a general methodology for coexistence studies between digital terrestrial television (DTT) and mobile broadband (MBB) systems in the ultra high frequency (UHF) broadcasting band. The methodology includes characterization of relevant field measurement scenarios and gives a step-by-step guideline on how to obtain reliable field measurement results to be used in conjunction with link budget analyses, laboratory measurements, and simulations. A survey of potential European coexistence scenarios and regulatory status is given to determine feasible future use scenarios for the UHF television (TV) broadcasting band. The DTT reception system behavior and performance are also described as they greatly affect the amount of spectrum potentially available for MBB use and determine the relevant coexistence field measurement scenarios. Simulation methods used in determining broadcast protection criteria and in coexistence studies are briefly described to demonstrate how the information obtained from field measurements can be used to improve their accuracy. The presented field measurement guidelines can be applied to any DTT-MBB coexistence scenarios and to a wide range of spectrum sharing and cognitive radio system coexistence measurements.

Joint Timing Synchronization and Channel Estimation Using Perfect Sequence in Uplink Time Domain Synchronous OFDMA

AbstractTime Domain Synchronous Orthogonal Frequency Division Multiple Access (TDS-OFDMA) is used in mobile broadband wireless access scheme in uplink transmission. This leads to multiple user interference due to timing offset and frequency offset. In this paper, the effect of timing offset and channel estimation in mobile broadband system is analysed. Time-space two dimensional structure is used in TDS-OFDMA and perfect sequence is used for guard interval to achieve perfect timing synchronization and channel estimation for each user. Simulations are performed for timing synchronization and channel estimation using perfect sequence under Urban channel, Indoor Office B channel and HIPER LAN-A channel. Simulation results show that the timing synchronization is achieved and channel estimation performance using perfect sequence is better than CAZAC and PN Sequences.

Multilayered Cavity Material Radial Line Slot Array Antenna with Improved Bandwidth for 5G Communication Application

Mobile broadband communication systems like the fifth generation (5G) will require large bandwidth allocation. Currently, the sweet spot is congested with no enough spectrum to support higher bandwidth allocation. The millimeter wave band is being explored to provide the needed spectrum with 28 GHz so far identified as a potential carrier frequency. Development of complimentary antennas for transmission and reception on the band therefore become necessary. This paper present the design of linearly polarized radial line slot array antenna at 28 GHz for mobile broadband communication system application. The antenna consists of radiating surface with radius ρ sitting on squared cavity and ground of side 2ρ. It is excited via a rear center mounted modified straight dielectric coated 50 Ω SSMA connector. The cavity is filled with layers of air space, low dielectric constant syntactic foam and high frequency laminate RT/duroid 5880. With ρ = 50 mm and a maximum total cavity height of 3.0 mm, the antenna was simulated using Computer Simulation Technology Microwave Studio 2014 software. A gain of 18.13 dB, directivity of 18.4 dBi, efficiency of 96 % and impedance bandwidth of up to 2.34 GHz were realized.

A cross-layer design for a software-defined millimeter-wave mobile broadband system

Heterogeneous networks, which deploy small cells in the mmWave band underlying the macrocell network, have attracted intense interest from both academia and industry. Different from the communication systems using lower carrier frequencies, mmWave communications have unique features, such as high propagation loss, directional communications, and sensitivity to blockage. Aiming to overcome the challenging problems in mmWave networks, such as interference management, spatial reuse, anti-blockage, QoS guarantee, and load balancing, we architecturally borrow the ideas of heterogeneous cloud radio access networks and software-defined networking to propose a software-defined mmWave mobile broadband system via a cross-layer design approach. In this architecture, a centralized controller is introduced by abstracting the control functions from the network layer to the physical layer. Through quantitative simulations in a realistic indoor scenario, we demonstrate the performance advantages of our system in terms of network throughput and flow throughput. This work is the first cross-layer and software-defined design for mmWave communications, which opens up an opportunity for mmWave communications to make a significant impact on future 5G networks.

Officer perceptions of the impact of mobile broadband technology on police operations

ABSTRACTResearch examining police departments' use of technology is underdeveloped relative to other areas of policing. This gap in the literature is troubling as policing models are becoming more data-driven and thus, relying more heavily on information technologies. Arguably, the most commonly utilised technology in policing practice, and examined in policing research, has been mobile computers. However, there has been little insight into the technological advancement in data communications that directly influence the functionality of mobile computers. This research seeks to inform this shortcoming by examining a police department that implemented a dedicated wireless mobile broadband system. A mixed-methods approach is employed within a medium-sized department in the northeast region of the USA. Survey data were gathered from 76 uniformed police personnel. Semi-structured interviews were conducted with key personnel to further contextualise survey results. Survey results suggest tentative support for improved time savings and execution of job tasks after the implementation of wireless broadband. Perceptions of mobile broadband impacts on information flow, quality, and accessibility appear positive. Considerations for future research and study limitations are discussed.

CogCell: cognitive interplay between 60 GHz picocells and 2.4/5 GHz hotspots in the 5G era

The rapid proliferation of wireless communication devices and the emergence of a variety of new applications have triggered investigations into next-generation mobile broadband systems, i.e. 5G. Legacy 2G-4G systems covering large areas were envisioned to serve both indoor and outdoor environments. However, in the 5G era, 80 percent of all traffic is expected to be generated indoors. Hence, the current approach of macrocell mobile networks, where there is no differentiation between indoors and outdoors, needs to be reconsidered. We envision 60 GHz mmWave picocell architecture to support highspeed indoor and hotspot communications. We envisage the 5G indoor network as a combination of, and interplay between, 2.4/5 GHz having robust coverage and 60 GHz links offering a high data rate. This requires intelligent coordination and cooperation. We propose a 60 GHz picocellular network architecture, called CogCell, leveraging ubiquitous WiFi. We propose to use 60 GHz for the data plane and 2.4/5GHz for the control plane. The hybrid network architecture considers an opportunistic fall-back to 2.4/5 GHz in case of poor connectivity in the 60 GHz domain. Further, to avoid the frequent re-beamforming in 60 GHz directional links due to mobility, we propose a cognitive module, a sensor- assisted intelligent beam switching procedure, that reduces communication overhead. We believe that the CogCell concept will help future indoor communications and possibly outdoor hotspots, where mobile stations and access points collaborate with each other to improve the user experience.