An Efficient Data Aggregation Algorithm for Cluster-based Sensor Network

Data aggregation in wireless sensor networks eliminates redundancy to improve bandwidth utilization and energy-efficiency of sensor nodes. One node, called the cluster leader, collects data from surrounding nodes and then sends the summarized information to upstream nodes. In this paper, we propose an algorithm to select a cluster leader that will perform data aggregation in a partially connected sensor network. The algorithm reduces the traffic flow inside the network by adaptively selecting the shortest route for packet routing to the cluster leader. We also describe a simulation framework for functional analysis of WSN applications taking our proposed algorithm as an exampl

Overlapping layers for prolonging network life time in multi-hop wireless sensor networks

Wireless sensor networks have been proposed as a practical solution for a wide range of applications due to their benefits of low cost, rapid deployment, self-organization capability, and cooperative data-processing. Many applications, such as military surveillance and habitat monitoring, require the deployment of large-scale sensor networks. A highly scalable and fault-tolerant network architecture, the Progressive Multi-hop Rotational Clustered (PMRC) structure has been proposed, which is suitable for constructing large-scale wireless sensor networks. However, similar to other multi-hop structures, the PMRC structure also suffers from the bottleneck problem; This thesis is focused on solving the bottleneck problem existing in the PMRC structure. First, the Overlapping Neighbor Layers (ONL) scheme is proposed to balance the energy consumption among cluster heads at different layers. Further, the Minimum Overlapping Neighbor Layers (MONL) scheme is proposed wherein the overlapped area between neighbor layers is gradually increased through network life time to achieve load balance and energy efficiency in the whole network area. Simulation results show that the MONL scheme significantly prolongs network life time and demonstrates steady performance on sensor networks with uniformly distributed sensor nodes. To further prolong the network life time, traffic-similar sensor nodes distribution combined with the MONL scheme is studied; The proposed overlapped layers schemes are proven to be effective in solving the bottleneck problem and prolonging network life time for PMRC-based networks. They can also be applied for other multi-hop cluster-based sensor networks. The traffic-similar nodes distribution concept can be applied in optimizing sensor network deployment to achieve desired network life time

An energy-efficient spectrum-aware reinforcement learning-based clustering algorithm for cognitive radio sensor networks

It is well-known that clustering partitions network into logical groups of nodes in order to achieve energy efficiency and to enhance dynamic channel access in cognitive radio through cooperative sensing. While the topic of energy efficiency has been well investigated in conventional wireless sensor networks, the latter has not been extensively explored. In this paper, we propose a reinforcement learning-based spectrum-aware clustering algorithm that allows a member node to learn the energy and cooperative sensing costs for neighboring clusters to achieve an optimal solution. Each member node selects an optimal cluster that satisfies pairwise constraints, minimizes network energy consumption and enhances channel sensing performance through an exploration technique. We first model the network energy consumption and then determine the optimal number of clusters for the network. The problem of selecting an optimal cluster is formulated as a Markov Decision Process (MDP) in the algorithm and the obtained simulation results show convergence, learning and adaptability of the algorithm to dynamic environment towards achieving an optimal solution. Performance comparisons of our algorithm with the Groupwise Spectrum Aware (GWSA)-based algorithm in terms of Sum of Square Error (SSE), complexity, network energy consumption and probability of detection indicate improved performance from the proposed approach. The results further reveal that an energy savings of 9% and a significant Primary User (PU) detection improvement can be achieved with the proposed approach

Análise de consumo de energia e processamento de sinais na plataforma MICAz

Monografia (graduação)—Universidade de Brasília, Faculdade de Tecnologia, 2014.Este trabalho investiga o consumo de energia dos motes MICAZ presentes nas redes de sensores. Inicialmente, o trabalho realiza a estimação do gasto de energia para aquisição de dados, processamento e transmissão. É utilizado um sinal eletrocardiográ co a m de realizar a estimação desses gastos, considerando que esse sinal passa pelos seguintes processamentos: transformada discreta de cosseno seguido do cálculo da variância dos componentes e Compressed Sensing. Esses processamentos são utilizados a m de reduzir o montante de dados a serem transmitidos e, consequentemente, reduzir o gasto de transmissão. Através das estimações realizadas, nota-se que a melhor estratégia para reduzir o consumo de transmissão e que ocasiona um menor aumento no processamento seria uma estratégia baseada somente na transformada discreta de cosseno. A partir dessa veri cação, são implementadas quatro aplicações na plataforma MICAZ, duas que utilizam a transformada de cosseno e duas que não a utilizam. As aplicações coletam dados sobre a temperatura ambiente e luminosidade ambiente. Para o caso das aplicações que utilizam a transformada de cosseno, caso os coe cientes sejam nulos, eles não seriam transmitidos, reduzindo assim o consumo de energia da transmissão. É veri cado uma redução do consumo de energia quando se utiliza a transformada em relação aos casos em que a transformada não é utilizada. Além do mais, ao comparar os sinais recebidos que utilizam a transformada de cosseno com os sinais que não utilizam a transformada, veri ca-se um erro quadrático médio pequeno, validando as aplicações que adotam a transformada. ___________________________________________________________________________ ABSTRACTThis study investigates the energy consumption of the motes MICAZ present in sensor networks. Initially, the work accomplishes the estimation of energy expenditure for data acquisition, processing and transmission. An electrocardiographic signal is used to perform the estimation of these costs, whereas this signal goes through the following processes: DCT followed by the calculation of the variance of components and Compressed Sensing. These processes are used to reduce the amount of data to be transmitted and thus reducing the cost of transmission. Through the estimations performed, it is noted that the best strategy to reduce the consumption of transmission and that causes a smaller increase in processing would be a strategy based only on the DCT. From this veri cation, four applications are implemented in MICAZ platform, two using the cosine transform and two which do not use it. The applications collect data of the environment temperature and environment light. For the case of applications that use cosine transform, the coe cients equal to zero are not transmitted, reducing the consumption of transmission. A reduction in energy consumption is observed when using the transform in relation to cases where the transform is not used. Furthermore, comparing the received signals using the cosine transform with signals that do not use the transform, it turns a small mean square error, validating applications that adopt the use of the transform

An augmentation algorithm for improving longevity in ad hoc wireless networks

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 71-74).This thesis presents an investigation into improving the longevity of wireless ad hoc networks. The primary contribution of this study is an augmentation algorithm that takes a two-dimensional network arrangement. and systematically adds augmented nodes to create a bi-connected topology. Simulations were run to compare the performance of these augmented networks with their initial layouts. Additionally, two different routing protocols were compared to evaluate their effects on network lifetime when combined with network augmentation. These routing protocols each take a unique approach to managing the network's energy resources. The results demonstrate that bi-connectivity is usually able to directly improve network lifetime. Additionally, it offers the greatest degree of improvement to networks which employ clever power management techniques.by Jonathan Charles Hyler.M.Eng

Ultra low power MAC layer wake-up frame scheme for low cost and low traffic wireless sensor networks

Wireless sensor networks, as a key enabling technology of Ubiquitous Computing, have been a booming research topic in the recent years. Upon designing a low-cost wireless sensor device, power consumption is one of the most important issues, because cheap batteries are normally the power suppliers. Since the RF transceiver is one of the biggest power consumers in such a sensor device, enabling the RF transceiver to sleep as much as possible is the preferred method to save power, which is normally realized by MAC layer duty cycle scheduling. This dissertation proposes aMAC layer wake-up-frame scheme to wake up an RF transceiver on-demand to minimize the standby waiting time in receive mode to save power. Analytical and simulation results show that, for a low-traffic wireless sensor network, this scheme gives significant system battery lifetime gain compared to the traditional methods. Furthermore, the combination of the wake-up-frame scheme and a complementary lowpower MAC protocol is discussed. Analytical computation and simulation prove that the combined scheme achieves a further optimized solution in the sense of power-saving, while other important system parameters, such as response time and channel efficiency, are limited to a reasonable range

Constructive Relay based Cooperative Routing in Mobile Ad hoc Networks

PhDMobile Ad hoc networks (MANETs) are flexible networks that transmit packets node-by-node along a route connecting a given source and destination. Frequent link breaks (due to node mobility) and quick exhaustion of energy (due to limited battery capacity) are two major problems impacting on the flexibility of MANETs. Cooperative communication is a key concept for improving the system lifetime and robustness and has attracted considerable attention. As a result, there is much published research concerning how to utilize cooperative communication in a MANET context. In the past few years, most cooperative technologies have focused on lower layer enhancements, such as with the Physical Layer and MAC Layer, and have become very mature. At the Network Layer, although some research has been proposed, issues still remain such as the lack of a systematically designed cooperative routing scheme (including route discovery, route reply, route enhancement and cooperative data forwarding), the use of cooperative communication for mobility resilience, and route selection (jointly considering the energy consumption, energy harvesting potential and link break probability). Driven by the above concerns, a novel Constructive Relay based CooPerative Routing (CRCPR) protocol based on a cross-layer design is proposed in this thesis. In CRCPR, we fi rst modify the traditional hello message format to carry some additional neighbour information. Based on this information, a key aspect of this protocol is to construct one or more small rhombus topologies within the MANET structure, which are stored and maintained in a COoPerative (COP) Table and Relay Table. Next, the route request procedure is re-designed to improve resilience to node mobility with a scheme called Last hop Replacement. Finally, assuming nodes are mostly battery-powered, destination node based route-decision criteria are explored that can consider energy consumption, energy harvesting and link break probability to determine an appropriate route across the MANET. As the hello message format is modi ed to carry additional information, the control overhead is increased. However, in order to improve the control message eficiency, a new generalised hello message broadcasting scheme entitled Adjust Classi ed Hello Scheme is developed, which can be deployed onto every routing protocol employing a hello mechanism. As well as designing a new routing protocol for MANETs, including route discovery, route selection, route reply, route maintenance, route enhancement and cooperative data forwarding, the proposed scheme is implemented within an Opnetbased simulation environment and evaluated under a variety of realistic conditions. The results con rm that CRCPR improves mobility resilience, saves energy via cooperative communication and reduces the control overhead associated with the hello message mechanism.Chinese Scholarship Counci