42,915 research outputs found
Data Transmission with Reduced Delay for Distributed Acoustic Sensors
This paper proposes a channel access control scheme fit to dense acoustic
sensor nodes in a sensor network. In the considered scenario, multiple acoustic
sensor nodes within communication range of a cluster head are grouped into
clusters. Acoustic sensor nodes in a cluster detect acoustic signals and
convert them into electric signals (packets). Detection by acoustic sensors can
be executed periodically or randomly and random detection by acoustic sensors
is event driven. As a result, each acoustic sensor generates their packets
(50bytes each) periodically or randomly over short time intervals
(400ms~4seconds) and transmits directly to a cluster head (coordinator node).
Our approach proposes to use a slotted carrier sense multiple access. All
acoustic sensor nodes in a cluster are allocated to time slots and the number
of allocated sensor nodes to each time slot is uniform. All sensor nodes
allocated to a time slot listen for packet transmission from the beginning of
the time slot for a duration proportional to their priority. The first node
that detect the channel to be free for its whole window is allowed to transmit.
The order of packet transmissions with the acoustic sensor nodes in the time
slot is autonomously adjusted according to the history of packet transmissions
in the time slot. In simulations, performances of the proposed scheme are
demonstrated by the comparisons with other low rate wireless channel access
schemes.Comment: Accepted to IJDSN, final preprinted versio
Boltzmann meets Nash: Energy-efficient routing in optical networks under uncertainty
Motivated by the massive deployment of power-hungry data centers for service
provisioning, we examine the problem of routing in optical networks with the
aim of minimizing traffic-driven power consumption. To tackle this issue,
routing must take into account energy efficiency as well as capacity
considerations; moreover, in rapidly-varying network environments, this must be
accomplished in a real-time, distributed manner that remains robust in the
presence of random disturbances and noise. In view of this, we derive a pricing
scheme whose Nash equilibria coincide with the network's socially optimum
states, and we propose a distributed learning method based on the Boltzmann
distribution of statistical mechanics. Using tools from stochastic calculus, we
show that the resulting Boltzmann routing scheme exhibits remarkable
convergence properties under uncertainty: specifically, the long-term average
of the network's power consumption converges within of its
minimum value in time which is at most ,
irrespective of the fluctuations' magnitude; additionally, if the network
admits a strict, non-mixing optimum state, the algorithm converges to it -
again, no matter the noise level. Our analysis is supplemented by extensive
numerical simulations which show that Boltzmann routing can lead to a
significant decrease in power consumption over basic, shortest-path routing
schemes in realistic network conditions.Comment: 24 pages, 4 figure
Energy-aware peering routing protocol for indoor hospital body area network communication
The recent research in Body Area Networks (BAN) is focused on making its communication more reliable, energy efficient, secure, and to better utilize system resources. In this paper we propose a novel BAN network architecture for indoor hospital environments, and a new mechanism of peer discovery with routing table construction that helps to reduce network traffic load, energy consumption, and improves BAN reliability. We have performed extensive simulations in the Castalia simulation environment to show that our proposed protocol has better performance in terms of reduced BAN traffic load, increased number of successful packets received by nodes, reduced number of packets forwarded by intermediate nodes, and overall lower energy consumption compared to other protocols
Adaptive Duty Cycling MAC Protocols Using Closed-Loop Control for Wireless Sensor Networks
The fundamental design goal of wireless sensor MAC protocols is to minimize unnecessary power consumption of the sensor nodes, because of its stringent resource constraints and ultra-power limitation. In existing MAC protocols in wireless sensor networks (WSNs), duty cycling, in which each node periodically cycles between the active and sleep states, has been introduced to reduce unnecessary energy consumption. Existing MAC schemes, however, use a fixed duty cycling regardless of multi-hop communication and traffic fluctuations. On the other hand, there is a tradeoff between energy efficiency and delay caused by duty cycling mechanism in multi-hop communication and existing MAC approaches only tend to improve energy efficiency with sacrificing data delivery delay. In this paper, we propose two different MAC schemes (ADS-MAC and ELA-MAC) using closed-loop control in order to achieve both energy savings and minimal delay in wireless sensor networks. The two proposed MAC schemes, which are synchronous and asynchronous approaches, respectively, utilize an adaptive timer and a successive preload frame with closed-loop control for adaptive duty cycling. As a result, the analysis and the simulation results show that our schemes outperform existing schemes in terms of energy efficiency and delivery delay
Predictive Duty Cycle Adaptation for Wireless Camera Networks
Wireless sensor networks (WSN) typically employ dynamic duty cycle schemes to efficiently handle different patterns of communication traffic in the network. However, existing duty cycling approaches are not suitable for event-driven WSN, in particular, camera-based networks designed to track humans and objects. A characteristic feature of such networks is the spatially-correlated bursty traffic that occurs in the vicinity of potentially highly mobile objects. In this paper, we propose a concept of indirect sensing in the MAC layer of a wireless camera network and an active duty cycle adaptation scheme based on Kalman filter that continuously predicts and updates the location of the object that triggers bursty communication traffic in the network. This prediction allows the camera nodes to alter their communication protocol parameters prior to the actual increase in the communication traffic. Our simulations demonstrate that our active adaptation strategy outperforms TMAC not only in terms of energy efficiency and communication latency, but also in terms of TIBPEA, a QoS metric for event-driven WSN
How to Choose the Relevant MAC Protocol for Wireless Smart Parking Urban Networks?
Parking sensor network is rapidly deploying around the world and is regarded
as one of the first implemented urban services in smart cities. To provide the
best network performance, the MAC protocol shall be adaptive enough in order to
satisfy the traffic intensity and variation of parking sensors. In this paper,
we study the heavy-tailed parking and vacant time models from SmartSantander,
and then we apply the traffic model in the simulation with four different kinds
of MAC protocols, that is, contention-based, schedule-based and two hybrid
versions of them. The result shows that the packet interarrival time is no
longer heavy-tailed while collecting a group of parking sensors, and then
choosing an appropriate MAC protocol highly depends on the network
configuration. Also, the information delay is bounded by traffic and MAC
parameters which are important criteria while the timely message is required.Comment: The 11th ACM International Symposium on Performance Evaluation of
Wireless Ad Hoc, Sensor, and Ubiquitous Networks (2014
Design and analysis of a beacon-less routing protocol for large volume content dissemination in vehicular ad hoc networks
Largevolumecontentdisseminationispursuedbythegrowingnumberofhighquality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authorsâ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well
Performance Comparison of Contention- and Schedule-based MAC Protocols in Urban Parking Sensor Networks
Network traffic model is a critical problem for urban applications, mainly
because of its diversity and node density. As wireless sensor network is highly
concerned with the development of smart cities, careful consideration to
traffic model helps choose appropriate protocols and adapt network parameters
to reach best performances on energy-latency tradeoffs. In this paper, we
compare the performance of two off-the-shelf medium access control protocols on
two different kinds of traffic models, and then evaluate their application-end
information delay and energy consumption while varying traffic parameters and
network density. From the simulation results, we highlight some limits induced
by network density and occurrence frequency of event-driven applications. When
it comes to realtime urban services, a protocol selection shall be taken into
account - even dynamically - with a special attention to energy-delay tradeoff.
To this end, we provide several insights on parking sensor networks.Comment: ACM International Workshop on Wireless and Mobile Technologies for
Smart Cities (WiMobCity) (2014
Mobile Edge Computing Empowers Internet of Things
In this paper, we propose a Mobile Edge Internet of Things (MEIoT)
architecture by leveraging the fiber-wireless access technology, the cloudlet
concept, and the software defined networking framework. The MEIoT architecture
brings computing and storage resources close to Internet of Things (IoT)
devices in order to speed up IoT data sharing and analytics. Specifically, the
IoT devices (belonging to the same user) are associated to a specific proxy
Virtual Machine (VM) in the nearby cloudlet. The proxy VM stores and analyzes
the IoT data (generated by its IoT devices) in real-time. Moreover, we
introduce the semantic and social IoT technology in the context of MEIoT to
solve the interoperability and inefficient access control problem in the IoT
system. In addition, we propose two dynamic proxy VM migration methods to
minimize the end-to-end delay between proxy VMs and their IoT devices and to
minimize the total on-grid energy consumption of the cloudlets, respectively.
Performance of the proposed methods are validated via extensive simulations
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