651 research outputs found
Opportunistic Networking for Improving the Energy Efficiency of Multi-Hop Cellular Networks
Relaying technologies can help address the capacity
and energy-efficiency challenges faced by cellular networks as a
result of the rapid increase in mobile data consumption. A nonnegligible
portion of such consumption corresponds to delay
tolerant services. This delay tolerance offers the possibility for
opportunistic networking to exploit contact opportunities
between mobile devices in order to reduce the impact of data
traffic on the cellular capacity and energy-efficiency without
sacrificing the end-user quality of service. In this context, this
paper investigates the use of opportunistic forwarding in MCNMR
(Multi-hop Cellular Networks with Mobile Relays) to reduce
energy consumption in the case of delay tolerant services. The
study proposes to exploit context information provided at a low
cost by the cellular infrastructure to efficiently select the
forwarding node in a two-hop MCN-MR scenario. The proposed
solution results in significant energy savings compared to
traditional single-hop cellular communications and other
forwarding solutions reported in the literatureThis work is supported in part by the Spanish Ministry of
Economy and Competitiveness and FEDER funds (TEC201126109),and the Local Government of Valencia with reference
ACIF/2010/161 and BEFPI/2012/06
Store, carry and forward for energy efficiency in multi-hop cellular networks with mobile relays
Abstract The wide scale adoption of smartphones is
boosting cellular data traffic with the consequent capacity
constraints of cellular systems and increase in energy
consumption. A significant portion of cellular data traffic can be
deemed as delay tolerant. Such tolerance offers possibilities for
designing novel communications and networking solutions that
can accommodate the delay tolerant cellular data traffic while
reducing their impact on the overall cellular capacity and energy
consumption. In this context, this work studies the use of
opportunistic store, carry and forward techniques in Multi-Hop
Cellular Networks (MCN) to reduce energy consumption for
delay tolerant traffic. The study focuses on two-hop MCN
networks using mobile relays (MCN-MR), and identifies the
optimum mobile relay location and the location from which the
relay should start forwarding the information to the cellular base
station in order to minimize the overall energy consumption. The
study shows that the use of opportunistic store, carry and
forward techniques in MCN-MR can significantly reduce energy
consumption compared to other solutions, including traditional
single-hop cellular systems or direct contact store, carry and
forward solutions.This work is supported in part by the Spanish Ministry of Economy and Competitiveness and FEDER funds (TEC2011–26109)and the Local Government of Valencia with reference ACIF/2010/161 and BEFPI/2012/06
Socio-economic aware data forwarding in mobile sensing networks and systems
The vision for smart sustainable cities is one whereby urban sensing is core to optimising city
operation which in turn improves citizen contentment. Wireless Sensor Networks are envisioned
to become pervasive form of data collection and analysis for smart cities but deployment of
millions of inter-connected sensors in a city can be cost-prohibitive. Given the ubiquity and
ever-increasing capabilities of sensor-rich mobile devices, Wireless Sensor Networks with Mobile
Phones (WSN-MP) provide a highly flexible and ready-made wireless infrastructure for future
smart cities. In a WSN-MP, mobile phones not only generate the sensing data but also relay the
data using cellular communication or short range opportunistic communication. The largest
challenge here is the efficient transmission of potentially huge volumes of sensor data over
sometimes meagre or faulty communications networks in a cost-effective way.
This thesis investigates distributed data forwarding schemes in three types of WSN-MP: WSN
with mobile sinks (WSN-MS), WSN with mobile relays (WSN-HR) and Mobile Phone Sensing
Systems (MPSS). For these dynamic WSN-MP, realistic models are established and distributed
algorithms are developed for efficient network performance including data routing and forwarding,
sensing rate control and and pricing. This thesis also considered realistic urban sensing
issues such as economic incentivisation and demonstrates how social network and mobility
awareness improves data transmission. Through simulations and real testbed experiments, it
is shown that proposed algorithms perform better than state-of-the-art schemes.Open Acces
Outage Performance of Two-Hop OFDM Systems with Spatially Random Decode-and-Forward Relays
In this paper, we analyze the outage performance of different multicarrier
relay selection schemes for two-hop orthogonal frequency-division multiplexing
(OFDM) systems in a Poisson field of relays. In particular, special emphasis is
placed on decode-and-forward (DF) relay systems, equipped with bulk and
per-subcarrier selection schemes, respectively. The exact expressions for
outage probability are derived in integrals for general cases. In addition,
asymptotic expressions for outage probability in the high signal-to-noise ratio
(SNR) region in the finite circle relay distribution region are determined in
closed forms for both relay selection schemes. Also, the outage probabilities
for free space in the infinite relay distribution region are derived in closed
forms. Meanwhile, a series of important properties related to cooperative
systems in random networks are investigated, including diversity, outage
probability ratio of two selection schemes and optimization of the number of
subcarriers in terms of system throughput. All analysis is numerically verified
by simulations. Finally, a framework for analyzing the outage performance of
OFDM systems with spatially random relays is constructed, which can be easily
modified to analyze other similar cases with different forwarding protocols,
location distributions and/or channel conditions
Next Generation Opportunistic Networking in Beyond 5G Networks
Beyond 5G networks are expected to support massive traffic through decentralized solutions and advanced networking mechanisms. This paper aims at contributing towards this vision through the integration of device-centric wireless networks, including Device-to-Device (D2D) communications, and the Next Generation of Opportunistic networking (NGO). This integration offers multiple communication modes such as opportunistic cellular and opportunistic D2D-aided communications. Previous studies have demonstrated the potential and benefits of this integration in terms of energy efficiency, spectral efficiency and traffic offloading. We propose an integration of device-centric wireless networks and NGO that is not driven by a precise knowledge of the presence of the links. The proposed technique utilizes a novel concept of graph to model the evolution of the networking conditions and network connectivity. Uncertainties and future conditions are included in the proposed graph model through anticipatory mobile networking to estimate the transmission energy cost of the different communication modes. Based on these estimates, the devices schedule their transmissions using the most efficient communication mode. These decisions are later revisited in real-time using more precise knowledge about the network state. The conducted evaluation shows that the proposed technique significantly reduces the energy consumption (from 60% to 90% depending on the scenario) compared to traditional single-hop cellular communications and performs closely to an ideal “oracle based” system with full knowledge of present and future events. The transmission and computational overheads of the proposed technique show small impact on such energy gains.This work has been partially funded by the Spanish Ministry of Science, Innovation and Universities, AEI, and FEDER funds (TEC2017-88612-R)the Ministry of Science, Innovation and Universities (IJC2018-036862-I)the UMH (‘Ayudas a la Investigación e Innovación de la Universidad Miguel Hernández de Elche 2018’)and by the European Commission under the H2020 REPLICATE (691735), SoBigData (654024) and AUTOWARE (723909) project
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