Current Issue : October - December Volume : 2016 Issue Number : 4 Articles : 7 Articles
Node localization is an important supporting technology in wireless sensor networks (WSNs). Traditional maximum likelihood\nestimation based localization methods (MLE) assume that measurement errors are independent of the distance between the\nanchor node and a target node. However, such an assumption may not reflect the physical characteristics of existing measurement\ntechniques, such as the widely used received signal strength indicator. To address this issue, we propose a distance-based MLE that\nconsiders measurement errors that depend on distance values in this paper. The proposed distance-based MLE is formulated as\na complicated nonlinear optimization problem. An exact solution is developed based on first-order optimal condition to improve\nthe efficiency of search. In addition, a two-dimensional search method is also presented. Simulation experiments are performed\nto demonstrate the effectiveness of this localization.The simulation results show that the distance-based localization method has\nbetter localization accuracy compared to other range-based localization methods....
A Wireless Sensors Network (WSN) is an ad-hoc network populated by small hand-held commodity\ndevices, running on batteries called stations or sensors. Often used in hostiles and sometimes\nunreachable environments, stations are subject to energetic constraints which can significantly\ndecrease the network life time. Permutation routing problem is mainly found in the literature of\nWSN. This problem occurs when some stations have items that belong either or not to them. The\ngoal is to send each item to its receiver. To solve this problem, several works are presented in the\nliterature. In this paper, we present a new permutation routing protocol for multi-hop wireless\nsensors network that, compared to recent work in the field is more efficient in terms of conservation\nof sensors� energy, which results in a longer life time of the network. Also, contrary to some\nother routing protocols which assume that the memory of the sensors is infinite, we show that the\nmemory size of the sensors is limited, which in our opinion is more realistic....
As the technology of the Internet of Things (IoT) becomesmore widely used in large-scalemonitoring networks, this paper proposes\nan optimized obtaining strategy (OFS) for large-scale sensormonitoring networks. First, because of the large-scale features of sensor\nnode network, this paper proposes a large-scale monitoring network area clustering optimization strategy. Second, based on the\ncharacteristics of regular changes in the sensed data in large-scale monitoring networks, this paper proposes a strategy for acquiring\nsensor data based on an adaptive frequency conversion. The OFS optimization strategy can prolong network lifetime, reduce the\ntransmission bandwidth resources, and reduce average energy consumption of the cluster head and network energy consumption....
Multipath routing is an alternative routing technique, which uses redundant paths to deliver data from source to destination.\nCompared to single path routing protocols, it can address reliability, delay, and energy consumption issues.Thus,multipath routing\nis a potential technique to overcome the long propagation delay and adverse link condition in underwater environment. However,\nthere are still some problems in multipath routing. For example, the multiple paths may interfere with each other and arouse large\nend-to-end delay difference amongst multiple paths. This paper proposes a novel multipath routing structure and a conflict-free\nalgorithm based on TDMA scheme.The forwarding nodes are selected based on the propagation delay and location information.\nThis special multiple routing structure not only can ensure parallel multiple transmission without collision, but also can get a small\nend-to-end delay difference amongst multiple paths. Simulation results show that the multipath routing scheme proposed in this\npaper outperforms the traditional strategy....
Accurate location information plays an important role in the performance of wireless sensor networks since many mission\napplications depend on it. This paper proposes a fully distributed localization algorithm based on the concept of data fusion,\nallowing the full intranodes information including the correlations among estimates to take part in the algorithm. By properly\nconstructing and updating the estimates as well as the corresponding covariance matrices, the algorithm can fuse intranodes\ninformation to generate more accurate estimates on the sensor locations with a fast speed. Finally, numerical simulations are given\nas examples to demonstrate the effectiveness of the algorithm....
The network-based mobility management is adapted to the OpenFlow architecture for mobility service at Software Defined\nNetworking (SDN), and data structure for mobility service is proposed. SDN is a newly proposed Internet architecture which\ndecouples the data and control planes, and mobility management is one of the most important issues in SDN. In order to provide\nmobilitymanagement service by utilizing the mobility scheme proposed earlier in a newnetwork environment, the existing mobility\nschemes need to be modified. Particularly, the characters of the network environment need to be considered when designing the\nfunction of the network entities and data structure. Our proposed mobility management scheme is focused on the centralized\ncontrolmechanism of SDN.We referred to ProxyMobile IPv6 (PMIPv6) andOpenFlow-based PMIPv6 with a centralized mobility\nmanagement controller (OPMIPv6-C). It has a merged data structure for the mobility service on SDN controller and minimizes\nthe number of switches which need flow table modification at handover. At the performance analysis chapter, we compare the\nsignaling cost at the registration and handover phase, packet delivery cost, and handover latency between the proposed scheme\nand OPMIPv6-C....
A number of nodes that are interested in the same content can be grouped into a cluster and the cluster head can be used to\nrelay the content received fromthe base station (BS) to the cluster members using device-to-multidevice (D2MD) communication.\nHowever, the data rate of suchmulticast communication depends on the worst channel among the cluster members and the cluster\nhead.The rate can be enhanced by increasing the transmit power; however, this approach may deteriorate energy efficiency (EE)\nperformance of the system. In this paper, we propose transmitting the content from more than one cluster head simultaneously. A\nnovel algorithm is proposed that selects the cluster heads to improve the data rate of the multicast communication while keeping\nthe total transmit power from the cluster heads constant.The cluster members receive power from all the cluster heads within the\ncluster and hence the received signal to noise power ratio improves. The improved received power makes communication at higher\ndata rates possible, thus reducing the total transmission time. Hence, the energy requirement per bit will reduce. Simulation results\nshow that 19% of reduction in energy per bit is possible by using more than one cluster head within the cluster....
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