178 research outputs found
Topology Construction in RPL Networks over Beacon-Enabled 802.15.4
In this paper, we propose a new scheme that allows coupling beacon-enabled
IEEE 802.15.4 with the RPL routing protocol while keeping full compliance with
both standards. We provide a means for RPL to pass the routing information to
Layer 2 before the 802.15.4 topology is created by encapsulating RPL DIO
messages in beacon frames. The scheme takes advantage of 802.15.4 command
frames to solicit RPL DIO messages. The effect of the command frames is to
reset the Trickle timer that governs sending DIO messages. We provide a
detailed analysis of the overhead incurred by the proposed scheme to understand
topology construction costs. We have evaluated the scheme using Contiki and the
instruction-level Cooja simulator and compared our results against the most
common scheme used for dissemination of the upper-layer information in
beacon-enabled PANs. The results show energy savings during the topology
construction phase and in the steady state
Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey
Wireless sensor networks (WSNs) consist of autonomous and resource-limited
devices. The devices cooperate to monitor one or more physical phenomena within
an area of interest. WSNs operate as stochastic systems because of randomness
in the monitored environments. For long service time and low maintenance cost,
WSNs require adaptive and robust methods to address data exchange, topology
formulation, resource and power optimization, sensing coverage and object
detection, and security challenges. In these problems, sensor nodes are to make
optimized decisions from a set of accessible strategies to achieve design
goals. This survey reviews numerous applications of the Markov decision process
(MDP) framework, a powerful decision-making tool to develop adaptive algorithms
and protocols for WSNs. Furthermore, various solution methods are discussed and
compared to serve as a guide for using MDPs in WSNs
The Beauty of the Commons: Optimal Load Sharing by Base Station Hopping in Wireless Sensor Networks
In wireless sensor networks (WSNs), the base station (BS) is a critical
sensor node whose failure causes severe data losses. Deploying multiple fixed
BSs improves the robustness, yet requires all BSs to be installed with large
batteries and large energy-harvesting devices due to the high energy
consumption of BSs. In this paper, we propose a scheme to coordinate the
multiple deployed BSs such that the energy supplies required by individual BSs
can be substantially reduced. In this scheme, only one BS is selected to be
active at a time and the other BSs act as regular sensor nodes. We first
present the basic architecture of our system, including how we keep the network
running with only one active BS and how we manage the handover of the role of
the active BS. Then, we propose an algorithm for adaptively selecting the
active BS under the spatial and temporal variations of energy resources. This
algorithm is simple to implement but is also asymptotically optimal under mild
conditions. Finally, by running simulations and real experiments on an outdoor
testbed, we verify that the proposed scheme is energy-efficient, has low
communication overhead and reacts rapidly to network changes
A Hybrid based Distributed Slot Scheduling Approach for WSN MAC
In Wireless Sensor Networks(WSNs), collision handling during transmission of data is an important challenge. MAC protocol plays a vital role in handling those collisions. Among different types of MAC protocols, schedule based MAC protocol is one where a valid schedule is prepared to handle the collision. The existing schedule based MAC protocols focus on preparing either a feasible schedule or an optimal schedule. In order to satisfy both feasibility as well as optimality feature, in this paper, we proposed a hybrid approach for slot scheduling that prepares a feasible schedule in a distributed manner and at the same time reduces the number of slots in the feasible schedule to achieve optimality. In this paper, we named this as Hybrid based Distributed Slot Scheduling (HDSS) approach. The proposed HDSS algorithm initially prepares a feasible schedule which is further tuned in quick time to prepare a valid schedule with a reduced number of slots. The reduction of the number of slots in the schedule improves the efficiency of data transmission in terms of latency. The simulation results show that the HDSS algorithm outperforms RD-TDMA with respect to both the number of slots allotted for a feasible schedule as well as the data transmission latency
Game theory framework for MAC parameter optimization in energy-delay constrained sensor networks
Optimizing energy consumption and end-to-end (e2e) packet delay in energy-constrained, delay-sensitive wireless sensor networks is a conflicting multiobjective optimization problem. We investigate the problem from a game theory perspective, where the two optimization objectives are considered as game players. The cost model of each player is mapped through a generalized optimization framework onto protocol-specific MAC parameters. From the optimization framework, a game is first defined by the Nash bargaining solution (NBS) to assure energy consumption and e2e delay balancing. Secondy, the Kalai-Smorodinsky bargaining solution (KSBS) is used to find an equal proportion of gain between players. Both methods offer a bargaining solution to the duty-cycle MAC protocol under different axioms. As a result, given the two performance requirements (i.e., the maximum latency tolerated by the application and the initial energy budget of nodes), the proposed framework allows to set tunable system parameters to reach a fair equilibrium point that dually minimizes the system latency and energy consumption. For illustration, this formulation is applied to six state-of-the-art wireless sensor network (WSN) MAC protocols: B-MAC, X-MAC, RI-MAC, SMAC, DMAC, and LMAC. The article shows the effectiveness and scalability of such a framework in optimizing protocol parameters that achieve a fair energy-delay performance trade-off under the application requirements
Reduce energy consumption in the wireless sensor network by using EEL-MAC protocol
Wireless Sensor Network (WSN) nodes are broadly used in various sectors. Over the years, WSN has emerged as an enabler to collect and process data from remote locations or disaster areas. WSNs rely on hardware simplicity to make sensor field deployments both affordable and long-lasting without maintenance support.
However, the WSN nodes experience a lot of problems such as, overhearing, collision, hidden terminal, idle listening and high latency, which resulted in high energy consumption, thus limiting the lifetime of the node. Moreover, WSN nodes are strongly dependent on their limited battery power, and replenishing them again is difficult. Therefore, this research investigates the energy-efficient Medium Access Control (MAC) protocols designed to extend both the lifetime by effective energy management through a reduction in idle time and increased sleep time for nodes to save energy. This study also aims to reduce the latency between nodes and sink
node. The EEL-MAC hybrid MAC protocol starts by a synchronization phase using TDMA to synchronize all nodes in the sensor field. In the second phase the scheme uses the CSMA mechanism for communication between nodes and the sink node. In this study makes two significant contributions to wireless sensor networks. First, the EEL-MAC protocol offers significant energy savings and prolongs network lifetime. The second contribution is the introduction of high response, by designing a one-hop communication to reduce both end-to-end delay and latency
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