25,078 research outputs found
FreeNet: Spectrum and Energy Harvesting Wireless Networks
The dramatic mobile data traffic growth is not only resulting in the spectrum
crunch but is also leading to exorbitant energy consumption. It is thus
desirable to liberate mobile and wireless networks from the constraint of the
spectrum scarcity and to rein in the growing energy consumption. This article
introduces FreeNet, figuratively synonymous to "Free Network", which engineers
the spectrum and energy harvesting techniques to alleviate the spectrum and
energy constraints by sensing and harvesting spare spectrum for data
communications and utilizing renewable energy as power supplies, respectively.
Hence, FreeNet increases the spectrum and energy efficiency of wireless
networks and enhances the network availability. As a result, FreeNet can be
deployed to alleviate network congestion in urban areas, provision broadband
services in rural areas, and upgrade emergency communication capacity. This
article provides a brief analysis of the design of FreeNet that accommodates
the dynamics of the spare spectrum and employs renewable energy
A study of research trends and issues in wireless ad hoc networks
Ad hoc network enables network creation on the fly without support of any
predefined infrastructure. The spontaneous erection of networks in anytime and
anywhere fashion enables development of various novel applications based on ad
hoc networks. However, at the same ad hoc network presents several new
challenges. Different research proposals have came forward to resolve these
challenges. This chapter provides a survey of current issues, solutions and
research trends in wireless ad hoc network. Even though various surveys are
already available on the topic, rapid developments in recent years call for an
updated account on this topic. The chapter has been organized as follows. In
the first part of the chapter, various ad hoc network's issues arising at
different layers of TCP/IP protocol stack are presented. An overview of
research proposals to address each of these issues is also provided. The second
part of the chapter investigates various emerging models of ad hoc networks,
discusses their distinctive properties and highlights various research issues
arising due to these properties. We specifically provide discussion on ad hoc
grids, ad hoc clouds, wireless mesh networks and cognitive radio ad hoc
networks. The chapter ends with presenting summary of the current research on
ad hoc network, ignored research areas and directions for further research
Exploiting the power of multiplicity: a holistic survey of network-layer multipath
The Internet is inherently a multipath network---for an underlying network
with only a single path connecting various nodes would have been debilitatingly
fragile. Unfortunately, traditional Internet technologies have been designed
around the restrictive assumption of a single working path between a source and
a destination. The lack of native multipath support constrains network
performance even as the underlying network is richly connected and has
redundant multiple paths. Computer networks can exploit the power of
multiplicity to unlock the inherent redundancy of the Internet. This opens up a
new vista of opportunities promising increased throughput (through concurrent
usage of multiple paths) and increased reliability and fault-tolerance (through
the use of multiple paths in backup/ redundant arrangements). There are many
emerging trends in networking that signify that the Internet's future will be
unmistakably multipath, including the use of multipath technology in datacenter
computing; multi-interface, multi-channel, and multi-antenna trends in
wireless; ubiquity of mobile devices that are multi-homed with heterogeneous
access networks; and the development and standardization of multipath transport
protocols such as MP-TCP.
The aim of this paper is to provide a comprehensive survey of the literature
on network-layer multipath solutions. We will present a detailed investigation
of two important design issues, namely the control plane problem of how to
compute and select the routes, and the data plane problem of how to split the
flow on the computed paths. The main contribution of this paper is a systematic
articulation of the main design issues in network-layer multipath routing along
with a broad-ranging survey of the vast literature on network-layer
multipathing. We also highlight open issues and identify directions for future
work
Survey of Important Issues in UAV Communication Networks
Unmanned Aerial Vehicles (UAVs) have enormous potential in the public and
civil domains. These are particularly useful in applications where human lives
would otherwise be endangered. Multi-UAV systems can collaboratively complete
missions more efficiently and economically as compared to single UAV systems.
However, there are many issues to be resolved before effective use of UAVs can
be made to provide stable and reliable context-specific networks. Much of the
work carried out in the areas of Mobile Ad Hoc Networks (MANETs), and Vehicular
Ad Hoc Networks (VANETs) does not address the unique characteristics of the UAV
networks. UAV networks may vary from slow dynamic to dynamic; have intermittent
links and fluid topology. While it is believed that ad hoc mesh network would
be most suitable for UAV networks yet the architecture of multi-UAV networks
has been an understudied area. Software Defined Networking (SDN) could
facilitate flexible deployment and management of new services and help reduce
cost, increase security and availability in networks. Routing demands of UAV
networks go beyond the needs of MANETS and VANETS. Protocols are required that
would adapt to high mobility, dynamic topology, intermittent links, power
constraints and changing link quality. UAVs may fail and the network may get
partitioned making delay and disruption tolerance an important design
consideration. Limited life of the node and dynamicity of the network leads to
the requirement of seamless handovers where researchers are looking at the work
done in the areas of MANETs and VANETs, but the jury is still out. As energy
supply on UAVs is limited, protocols in various layers should contribute
towards greening of the network. This article surveys the work done towards all
of these outstanding issues, relating to this new class of networks, so as to
spur further research in these areas.Comment: arXiv admin note: substantial text overlap with arXiv:1304.3904 by
other author
Joint Inter-flow Network Coding and Opportunistic Routing in Multi-hop Wireless Mesh Networks: A Comprehensive Survey
Network coding and opportunistic routing are two recognized innovative ideas
to improve the performance of wireless networks by utilizing the broadcast
nature of the wireless medium. In the last decade, there has been considerable
research on how to synergize inter-flow network coding and opportunistic
routing in a single joint protocol outperforming each in any scenario. This
paper explains the motivation behind the integration of these two techniques,
and highlights certain scenarios in which the joint approach may even degrade
the performance, emphasizing the fact that their synergistic effect cannot be
accomplished with a naive and perfunctory combination. This survey paper also
provides a comprehensive taxonomy of the joint protocols in terms of their
fundamental components and associated challenges, and compares existing joint
protocols. We also present concluding remarks along with an outline of future
research directions.Comment: 51 pages, 17 figure
Effective Capacity in Wireless Networks: A Comprehensive Survey
Low latency applications, such as multimedia communications, autonomous
vehicles, and Tactile Internet are the emerging applications for
next-generation wireless networks, such as 5th generation (5G) mobile networks.
Existing physical-layer channel models, however, do not explicitly consider
quality-of-service (QoS) aware related parameters under specific delay
constraints. To investigate the performance of low-latency applications in
future networks, a new mathematical framework is needed. Effective capacity
(EC), which is a link-layer channel model with QoS-awareness, can be used to
investigate the performance of wireless networks under certain statistical
delay constraints. In this paper, we provide a comprehensive survey on existing
works, that use the EC model in various wireless networks. We summarize the
work related to EC for different networks such as cognitive radio networks
(CRNs), cellular networks, relay networks, adhoc networks, and mesh networks.
We explore five case studies encompassing EC operation with different design
and architectural requirements. We survey various delay-sensitive applications
such as voice and video with their EC analysis under certain delay constraints.
We finally present the future research directions with open issues covering EC
maximization
Resource Management of energy-aware Cognitive Radio Networks and cloud-based Infrastructures
The field of wireless networks has been rapidly developed during the past
decade due to the increasing popularity of the mobile devices. The great demand
for mobility and connectivity makes wireless networking a field whose
continuous technological development is very important as new challenges and
issues are arising. Many scientists and researchers are currently engaged in
developing new approaches and optimization methods in several topics of
wireless networking. This survey paper study works from the following topics:
Cognitive Radio Networks, Interactive Broadcasting, Energy Efficient Networks,
Cloud Computing and Resource Management, Interactive Marketing and
Optimization
Learning-based Application-Agnostic 3D NoC Design for Heterogeneous Manycore Systems
The rising use of deep learning and other big-data algorithms has led to an
increasing demand for hardware platforms that are computationally powerful, yet
energy-efficient. Due to the amount of data parallelism in these algorithms,
high-performance 3D manycore platforms that incorporate both CPUs and GPUs
present a promising direction. However, as systems use heterogeneity (e.g., a
combination of CPUs, GPUs, and accelerators) to improve performance and
efficiency, it becomes more pertinent to address the distinct and likely
conflicting communication requirements (e.g., CPU memory access latency or GPU
network throughput) that arise from such heterogeneity. Unfortunately, it is
difficult to quickly explore the hardware design space and choose appropriate
tradeoffs between these heterogeneous requirements. To address these
challenges, we propose the design of a 3D Network-on-Chip (NoC) for
heterogeneous manycore platforms that considers the appropriate design
objectives for a 3D heterogeneous system and explores various tradeoffs using
an efficient ML-based multi-objective optimization technique. The proposed
design space exploration considers the various requirements of its
heterogeneous components and generates a set of 3D NoC architectures that
efficiently trades off these design objectives. Our findings show that by
jointly considering these requirements (latency, throughput, temperature, and
energy), we can achieve 9.6% better Energy-Delay Product on average at nearly
iso-temperature conditions when compared to a thermally-optimized design for 3D
heterogeneous NoCs. More importantly, our results suggest that our 3D NoCs
optimized for a few applications can be generalized for unknown applications as
well. Our results show that these generalized 3D NoCs only incur a 1.8%
(36-tile system) and 1.1% (64-tile system) average performance loss compared to
application-specific NoCs.Comment: Published in IEEE Transactions on Computer
Wireless Network Design for Control Systems: A Survey
Wireless networked control systems (WNCS) are composed of spatially
distributed sensors, actuators, and con- trollers communicating through
wireless networks instead of conventional point-to-point wired connections. Due
to their main benefits in the reduction of deployment and maintenance costs,
large flexibility and possible enhancement of safety, WNCS are becoming a
fundamental infrastructure technology for critical control systems in
automotive electrical systems, avionics control systems, building management
systems, and industrial automation systems. The main challenge in WNCS is to
jointly design the communication and control systems considering their tight
interaction to improve the control performance and the network lifetime. In
this survey, we make an exhaustive review of the literature on wireless network
design and optimization for WNCS. First, we discuss what we call the critical
interactive variables including sampling period, message delay, message
dropout, and network energy consumption. The mutual effects of these
communication and control variables motivate their joint tuning. We discuss the
effect of controllable wireless network parameters at all layers of the
communication protocols on the probability distribution of these interactive
variables. We also review the current wireless network standardization for WNCS
and their corresponding methodology for adapting the network parameters.
Moreover, we discuss the analysis and design of control systems taking into
account the effect of the interactive variables on the control system
performance. Finally, we present the state-of-the-art wireless network design
and optimization for WNCS, while highlighting the tradeoff between the
achievable performance and complexity of various approaches. We conclude the
survey by highlighting major research issues and identifying future research
directions.Comment: 37 pages, 17 figures, 4 table
Opportunistic Spectrum Sharing in Dynamic Access Networks: Deployment Challenges, Optimizations, Solutions, and Open Issues
In this paper, we investigate the issue of spectrum assignment in CRNs and
examine various opportunistic spectrum access approaches proposed in the
literature. We provide insight into the efficiency of such approaches and their
ability to attain their design objectives. We discuss the factors that impact
the selection of the appropriate operating channel(s), including the important
interaction between the cognitive linkquality conditions and the time-varying
nature of PRNs. Protocols that consider such interaction are described. We
argue that using best quality channels does not achieve the maximum possible
throughput in CRNs (does not provide the best spectrum utilization). The impact
of guard bands on the design of opportunistic spectrum access protocols is also
investigated. Various complementary techniques and optimization methods are
underlined and discussed, including the utilization of variablewidth spectrum
assignment, resource virtualization, full-duplex capability, cross-layer
design, beamforming and MIMO technology, cooperative communication, network
coding, discontinuousOFDM technology, and software defined radios. Finally, we
highlight several directions for future research in this field
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