4 research outputs found

    Modular Energy Efficient Protocols for Lower Layers of Wireless Sensor Networks

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    Wireless sensor networks (WSNs) emerged as one of the compelling research areas in recent years. It has produced promising solutions for several potential applications such as intrusion detection, target detection, industrial automation, environmental monitoring, surveillance and military systems, medical diagnosing systems, tactical systems, etc. WSNs consist of small size of sensor nodes that are disseminated in a targeted area to monitor the events for collecting the data of interest. Meanwhile, WSNs face many challenging problems such as high energy consumption, network scalability and mobility. These problems profoundly affect the lifetime of the network, limit the access to several WSN application areas, and the Quality of Service (QoS) provision parameters including throughput, latency, bandwidth, data buffering, resource constraints, data redundancy, and medium reliability. Although, there has been significant research conducted in WSNs over the last few years to maintain a high standard of communication, especially coverage, challenges of high power consumption, mobility and scalability to name a few. The major problem with WSNs at the low layers are the excessive energy consumption by the sensor’s transceiver. Other related challenges are mobility and scalability that limit the QoS provision. To handle these issues, novel modular energy efficient protocols are proposed for lower layers of WSNs. These modular based protocols improve the energy consumption, providing cross-layering support to handle mobility, scalability and data redundancy. In addition, there is a protocol that automates handling the idle listening process. Other protocols optimize data frame format for faster channel access, data frame transfer, managing acknowledgement time and retry transmission, check the capability of sensing the nature of environment to decide to use either active or passive mode that help save energy, determine shortest efficient path, packet generation rate, automatic active and sleep mode, smart queuing, data aggregation and dynamically selection of the cluster head node. All these features ensure the QoS provision and resolve many problems introduced by mobility and scalability for multiple application areas especially disaster recovery, hospital monitoring system, remotely handling the static and mobile objects and battlefield surveillance systems. Finally, modular energy efficient protocols are simulated, and results demonstrate the validity and compatibility of the proposed approaches for multiple WSNs application areas

    Supporting bursty traffic in wireless sensor networks through a distributed advertisement-based TDMA protocol (ATMA)

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    Nodes in wireless sensor networks (WSNs) are battery powered and oftentimes deployed in remote and hostile locations. Energy conservation is, therefore, one of the primary goals of MAC protocols designed for these networks. Contention-based protocols employ static or variable duty cycles to minimize energy dissipated in idle listening. TDMA-based protocols, on the other hand, use reservation and scheduling to minimize energy loss. Further energy savings may be obtained by taking the nature of the network traffic into consideration. Several WSN applications such as surveillance applications and habitat monitoring applications generate bursty traffic. In this paper, we combine the advantages of contention-based and TDMA-based protocols to form Advertisement-based Time-division Multiple Access (ATMA), a distributed TDMA-based MAC protocol for WSNs, that utilizes the bursty nature of the traffic to prevent energy waste through advertisements and reservations for data slots. We provide detailed comparisons of the ATMA protocol with contention-based protocols (S-MAC, T-MAC and ADV-MAC), a TDMA-based protocol (TRAMA) and hybrid protocols (Z-MAC and IEEE 802.15.4) through extensive simulations and qualitative analysis. The simulation results show that with bursty traffic, ATMA outperforms these existing protocols in terms of energy consumption with reductions of up to 80%, while providing the best packet delivery ratio (close to 100%) and latency among all the investigated protocols for several simulation scenarios studied.Peer ReviewedPostprint (published version

    Advertisement-based energy efficient medium access protocols for wireless sensor networks

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    Thesis (Ph. D.)--University of Rochester. Dept. of Electrical and Computer Engineering, 2013One of the main challenges that prevents the large-scale deployment of Wireless Sensor Networks (WSNs) is providing the applications with the required quality of service (QoS) given the sensor nodes' limited energy supplies. WSNs are an important tool in supporting applications ranging from environmental and industrial monitoring, to battlefield surveillance and traffic control, among others. Most of these applications require sensors to function for long periods of time without human intervention and without battery replacement. Therefore, energy conservation is one of the main goals for protocols for WSNs. Energy conservation can be performed in different layers of the protocol stack. In particular, as the medium access control (MAC) layer can access and control the radio directly, large energy savings is possible through intelligent MAC protocol design. To maximize the network lifetime, MAC protocols for WSNs aim to minimize idle listening of the sensor nodes, packet collisions, and overhearing. Several approaches such as duty cycling and low power listening have been proposed at the MAC layer to achieve energy efficiency. In this thesis, I explore the possibility of further energy savings through the advertisement of data packets in the MAC layer. In the first part of my research, I propose Advertisement-MAC or ADV-MAC, a new MAC protocol for WSNs that utilizes the concept of advertising for data contention. This technique lets nodes listen dynamically to any desired transmission and sleep during transmissions not of interest. This minimizes the energy lost in idle listening and overhearing while maintaining an adaptive duty cycle to handle variable loads. Additionally, ADV-MAC enables energy ecient MAC-level multicasting. An analytical model for the packet delivery ratio and the energy consumption of the protocol is also proposed. The analytical model is verified with simulations and is used to choose an optimal value of the advertisement period. Simulations show that the optimized ADV-MAC provides substantial energy gains (50% to 70% less than other MAC protocols for WSNs such as T-MAC and S-MAC for the scenarios investigated) while faring as well as T-MAC in terms of packet delivery ratio and latency. Although ADV-MAC provides substantial energy gains over S-MAC and T-MAC, it is not optimal in terms of energy savings because contention is done twice - once in the Advertisement Period and once in the Data Period. In the next part of my research, the second contention in the Data Period is eliminated and the advantages of contention-based and TDMA-based protocols are combined to form Advertisement based Time-division Multiple Access (ATMA), a distributed TDMA-based MAC protocol for WSNs. ATMA utilizes the bursty nature of the traffic to prevent energy waste through advertisements and reservations for data slots. Extensive simulations and qualitative analysis show that with bursty traffic, ATMA outperforms contention-based protocols (S-MAC, T-MAC and ADV-MAC), a TDMA based protocol (TRAMA) and hybrid protocols (Z-MAC and IEEE 802.15.4). ATMA provides energy reductions of up to 80%, while providing the best packet delivery ratio (close to 100%) and latency among all the investigated protocols. Simulations alone cannot reflect many of the challenges faced by real implementations of MAC protocols, such as clock-drift, synchronization, imperfect physical layers, and irregular interference from other transmissions. Such issues may cripple a protocol that otherwise performs very well in software simulations. Hence, to validate my research, I conclude with a hardware implementation of the ATMA protocol on SORA (Software Radio), developed by Microsoft Research Asia. SORA is a reprogrammable Software Defined Radio (SDR) platform that satisfies the throughput and timing requirements of modern wireless protocols while utilizing the rich general purpose PC development environment. Experimental results obtained from the hardware implementation of ATMA closely mirror the simulation results obtained for a single hop network with 4 nodes

    Supporting bursty traffic in wireless sensor networks through a distributed advertisement-based TDMA protocol (ATMA)

    No full text
    Nodes in wireless sensor networks (WSNs) are battery powered and oftentimes deployed in remote and hostile locations. Energy conservation is, therefore, one of the primary goals of MAC protocols designed for these networks. Contention-based protocols employ static or variable duty cycles to minimize energy dissipated in idle listening. TDMA-based protocols, on the other hand, use reservation and scheduling to minimize energy loss. Further energy savings may be obtained by taking the nature of the network traffic into consideration. Several WSN applications such as surveillance applications and habitat monitoring applications generate bursty traffic. In this paper, we combine the advantages of contention-based and TDMA-based protocols to form Advertisement-based Time-division Multiple Access (ATMA), a distributed TDMA-based MAC protocol for WSNs, that utilizes the bursty nature of the traffic to prevent energy waste through advertisements and reservations for data slots. We provide detailed comparisons of the ATMA protocol with contention-based protocols (S-MAC, T-MAC and ADV-MAC), a TDMA-based protocol (TRAMA) and hybrid protocols (Z-MAC and IEEE 802.15.4) through extensive simulations and qualitative analysis. The simulation results show that with bursty traffic, ATMA outperforms these existing protocols in terms of energy consumption with reductions of up to 80%, while providing the best packet delivery ratio (close to 100%) and latency among all the investigated protocols for several simulation scenarios studied.Peer Reviewe
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