2,410 research outputs found
An Overview of Signal Processing Techniques for Millimeter Wave MIMO Systems
Communication at millimeter wave (mmWave) frequencies is defining a new era
of wireless communication. The mmWave band offers higher bandwidth
communication channels versus those presently used in commercial wireless
systems. The applications of mmWave are immense: wireless local and personal
area networks in the unlicensed band, 5G cellular systems, not to mention
vehicular area networks, ad hoc networks, and wearables. Signal processing is
critical for enabling the next generation of mmWave communication. Due to the
use of large antenna arrays at the transmitter and receiver, combined with
radio frequency and mixed signal power constraints, new multiple-input
multiple-output (MIMO) communication signal processing techniques are needed.
Because of the wide bandwidths, low complexity transceiver algorithms become
important. There are opportunities to exploit techniques like compressed
sensing for channel estimation and beamforming. This article provides an
overview of signal processing challenges in mmWave wireless systems, with an
emphasis on those faced by using MIMO communication at higher carrier
frequencies.Comment: Submitted to IEEE Journal of Selected Topics in Signal Processin
A Survey of Millimeter Wave (mmWave) Communications for 5G: Opportunities and Challenges
With the explosive growth of mobile data demand, the fifth generation (5G)
mobile network would exploit the enormous amount of spectrum in the millimeter
wave (mmWave) bands to greatly increase communication capacity. There are
fundamental differences between mmWave communications and existing other
communication systems, in terms of high propagation loss, directivity, and
sensitivity to blockage. These characteristics of mmWave communications pose
several challenges to fully exploit the potential of mmWave communications,
including integrated circuits and system design, interference management,
spatial reuse, anti-blockage, and dynamics control. To address these
challenges, we carry out a survey of existing solutions and standards, and
propose design guidelines in architectures and protocols for mmWave
communications. We also discuss the potential applications of mmWave
communications in the 5G network, including the small cell access, the cellular
access, and the wireless backhaul. Finally, we discuss relevant open research
issues including the new physical layer technology, software-defined network
architecture, measurements of network state information, efficient control
mechanisms, and heterogeneous networking, which should be further investigated
to facilitate the deployment of mmWave communication systems in the future 5G
networks.Comment: 17 pages, 8 figures, 7 tables, Journal pape
A Survey on Non-Orthogonal Multiple Access for 5G Networks: Research Challenges and Future Trends
Non-orthogonal multiple access (NOMA) is an essential enabling technology for
the fifth generation (5G) wireless networks to meet the heterogeneous demands
on low latency, high reliability, massive connectivity, improved fairness, and
high throughput. The key idea behind NOMA is to serve multiple users in the
same resource block, such as a time slot, subcarrier, or spreading code. The
NOMA principle is a general framework, and several recently proposed 5G
multiple access schemes can be viewed as special cases. This survey provides an
overview of the latest NOMA research and innovations as well as their
applications. Thereby, the papers published in this special issue are put into
the content of the existing literature. Future research challenges regarding
NOMA in 5G and beyond are also discussed.Comment: to appear in IEEE JSAC, 201
Wireless Terahertz System Architectures for Networks Beyond 5G
The present white paper focuses on the system requirements of TERRANOVA.
Initially details the key use cases for the TERRANOVA technology and presents
the description of the network architecture. In more detail, the use cases are
classified into two categories, namely backhaul & fronthaul and access and
small cell backhaul. The first category refers to fibre extender,
point-to-point and redundancy applications, whereas the latter is designed to
support backup connection for small and medium-sized enterprises (SMEs),
internet of things (IoT) dense environments, data centres, indoor wireless
access, ad hoc networks, and last mile access. Then, it provides the networks
architecture for the TERRANOVA system as well as the network elements that need
to be deployed. The use cases are matched to specific technical scenarios,
namely outdoor fixed point-to-point (P2P), outdoor/indoor individual
point-to-multipoint (P2MP), and outdoor/indoor "quasi"-omnidirection, and the
key performance requirements of each scenario are identified. Likewise, we
present the breakthrough novel technology concepts, including the joint design
of baseband signal processing for the complete optical and wireless link, the
development of broadband and spectrally efficient RF-frontends for frequencies
>275 GHz, as well as channel modelling, waveforms, antenna array and
multiple-access schemes design, which we are going to use in order to satisfy
the presented requirements. Next, an overview of the required new
functionalities in both physical (PHY) layer and medium access control (MAC)
layers in the TERRANOVA system architecture will be given. Finally, the
individual enablers of the TERRANOVA system are combined to develop particular
candidate architectures for each of the three technical scenarios.Comment: 73 pages, 31 figures, 7 tables. arXiv admin note: text overlap with
arXiv:1503.00697 by other author
Five Disruptive Technology Directions for 5G
New research directions will lead to fundamental changes in the design of
future 5th generation (5G) cellular networks. This paper describes five
technologies that could lead to both architectural and component disruptive
design changes: device-centric architectures, millimeter Wave, Massive-MIMO,
smarter devices, and native support to machine-2-machine. The key ideas for
each technology are described, along with their potential impact on 5G and the
research challenges that remain
A Survey on Legacy and Emerging Technologies for Public Safety Communications
Effective emergency and natural disaster management depend on the efficient
mission-critical voice and data communication between first responders and
victims. Land Mobile Radio System (LMRS) is a legacy narrowband technology used
for critical voice communications with limited use for data applications.
Recently Long Term Evolution (LTE) emerged as a broadband communication
technology that has a potential to transform the capabilities of public safety
technologies by providing broadband, ubiquitous, and mission-critical voice and
data support. For example, in the United States, FirstNet is building a
nationwide coast-to-coast public safety network based of LTE broadband
technology. This paper presents a comparative survey of legacy and the
LTE-based public safety networks, and discusses the LMRS-LTE convergence as
well as mission-critical push-to-talk over LTE. A simulation study of LMRS and
LTE band class 14 technologies is provided using the NS-3 open source tool. An
experimental study of APCO-25 and LTE band class 14 is also conducted using
software-defined radio, to enhance the understanding of the public safety
systems. Finally, emerging technologies that may have strong potential for use
in public safety networks are reviewed.Comment: Accepted at IEEE Communications Surveys and Tutorial
Massive MIMO and Millimeter Wave for 5G Wireless HetNet: Potentials and Challenges
There have been active research activities worldwide in developing the
next-generation 5G wireless network. The 5G network is expected to support
significantly large amount of mobile data traffic and huge number of wireless
connections, achieve better cost- and energy-efficiency as well as quality of
service (QoS) in terms of communication delay, reliability and security. To
this end, the 5G wireless network should exploit potential gains in different
network dimensions including super dense and heterogeneous deployment of cells
and massive antenna arrays (i.e., massive multiple input multiple output (MIMO)
technologies) and utilization of higher frequencies, in particular millimeter
wave (mmWave) frequencies. This article discusses potentials and challenges of
the 5G heterogeneous wireless network (HetNet) which incorporates massive MIMO
and mmWave technologies. We will first provide the typical requirements of the
5G wireless network. Then, the significance of massive MIMO and mmWave in
engineering the future 5G HetNet is discussed in detail. Potential challenges
associated with the design of such 5G HetNet are discussed. Finally, we provide
some case studies, which illustrate the potential benefits of the considered
technologies.Comment: IEEE Vehicular Technology Magazine (To appear
Modeling and Analyzing Millimeter Wave Cellular Systems
We provide a comprehensive overview of mathematical models and analytical
techniques for millimeter wave (mmWave) cellular systems. The two fundamental
physical differences from conventional Sub-6GHz cellular systems are (i)
vulnerability to blocking, and (ii) the need for significant directionality at
the transmitter and/or receiver, which is achieved through the use of large
antenna arrays of small individual elements. We overview and compare models for
both of these factors, and present a baseline analytical approach based on
stochastic geometry that allows the computation of the statistical
distributions of the downlink signal-to-interference-plus-noise ratio (SINR)
and also the per link data rate, which depends on the SINR as well as the
average load. There are many implications of the models and analysis: (a)
mmWave systems are significantly more noise-limited than at Sub-6GHz for most
parameter configurations; (b) initial access is much more difficult in mmWave;
(c) self-backhauling is more viable than in Sub-6GHz systems which makes
ultra-dense deployments more viable, but this leads to increasingly
interference-limited behavior; and (d) in sharp contrast to Sub-6GHz systems
cellular operators can mutually benefit by sharing their spectrum licenses
despite the uncontrolled interference that results from doing so. We conclude
by outlining several important extensions of the baseline model, many of which
are promising avenues for future research.Comment: 50 pages, 10 figures, submitted to IEEE Trans. Communications,
invited pape
Millimeter Wave Cellular Wireless Networks: Potentials and Challenges
Millimeter wave (mmW) frequencies between 30 and 300 GHz are a new frontier
for cellular communication that offers the promise of orders of magnitude
greater bandwidths combined with further gains via beamforming and spatial
multiplexing from multi-element antenna arrays. This paper surveys measurements
and capacity studies to assess this technology with a focus on small cell
deployments in urban environments. The conclusions are extremely encouraging;
measurements in New York City at 28 and 73 GHz demonstrate that, even in an
urban canyon environment, significant non-line-of-sight (NLOS) outdoor,
street-level coverage is possible up to approximately 200 m from a potential
low power micro- or picocell base station. In addition, based on statistical
channel models from these measurements, it is shown that mmW systems can offer
more than an order of magnitude increase in capacity over current
state-of-the-art 4G cellular networks at current cell densities. Cellular
systems, however, will need to be significantly redesigned to fully achieve
these gains. Specifically, the requirement of highly directional and adaptive
transmissions, directional isolation between links and significant
possibilities of outage have strong implications on multiple access, channel
structure, synchronization and receiver design. To address these challenges,
the paper discusses how various technologies including adaptive beamforming,
multihop relaying, heterogeneous network architectures and carrier aggregation
can be leveraged in the mmW context.Comment: 17 pages, 15 figures. arXiv admin note: text overlap with
arXiv:1312.492
A Survey on High-Speed Railway Communications: A Radio Resource Management Perspective
High-speed railway (HSR) communications will become a key feature supported
by intelligent transportation communication systems. The increasing demand for
HSR communications leads to significant attention on the study of radio
resource management (RRM), which enables efficient resource utilization and
improved system performance. RRM design is a challenging problem due to
heterogenous quality of service (QoS) requirements and dynamic characteristics
of HSR wireless communications. The objective of this paper is to provide an
overview on the key issues that arise in the RRM design for HSR wireless
communications. A detailed description of HSR communication systems is first
presented, followed by an introduction on HSR channel models and
characteristics, which are vital to the cross-layer RRM design. Then we provide
a literature survey on state-of-the-art RRM schemes for HSR wireless
communications, with an in-depth discussion on various RRM aspects including
admission control, mobility management, power control and resource allocation.
Finally, this paper outlines the current challenges and open issues in the area
of RRM design for HSR wireless communications.Comment: 40 pages, 10 figures. Submitted to Computer Communication
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