Central Base Station Research Articles

LOCATION AWARE CLUSTER BASED ROUTING IN WIRELESS SENSOR NETWORKS

Wireless sensor nodes are usually embedded in the physical environment and report sensed data to a central base station. Clustering is one of the most challenging issues in wireless sensor networks. This paper proposes a new cluster scheme for wireless sensor network by modified the K means clustering algorithm. Sensor nodes are deployed in a harsh environment and randomly scattered in the region of interest and are deployed in a flat architecture. The transmission of packet will reduce the network lifetime. Thus, clustering scheme is required to avoid network traffic and increase overall network lifetime. In order to cluster the sensor nodes that are deployed in the sensor network, the location information of each sensor node should be known. By knowing the location of the each sensor node in the wireless sensor network, clustering is formed based on the highest residual energy and minimum distance from the base station. Among the group of nodes, one node is elected as a cluster head using centroid method. The minimum distance between the cluster node’s and the centroid point is elected as a cluster head. Clustering of nodes can minimize the residual energy and maximize the network performance. This improves the overall network lifetime and reduces network traffic.

Effectiveness of a Novel Power Control Algorithm in Heart Rate Monitoring of a Mobile Adult: Energy Efficiency Comparison with Fixed Power Transmission

In this paper, experiments are conducted to evaluate the efficacy of a novel adaptive power control algorithm in terms of energy efficiency in heart rate monitoring scenario of a mobile adult in a typical home environment. As part of health care, persons with heart related problems are required to be monitored by logging for example, their heart rate on a regular basis to check for any anomaly. At the same time, it is expected that the person in question should be able to move freely within the given facility. The wireless sensors that are attached to the person send periodic data to the central base station. Since the person is mobile, the distance between the transmitting sensor and the base station changes with time. Since the signal path-loss is primarily dependent on distance and the number and type of obstructions between the transmitter and the receiver, it may be wise to use transmission power control to modulate the transmit power. Using power control, the sensor can adjust the level that is sufficient to send the data through the wireless channel without wasting energy. Conservation of energy is critical in wireless sensor network scenarios because they are powered by batteries which have limited lifetime. A critical application like the heart rate monitoring sensor is expected to operate for a reasonable amount of time before the battery dies. The novel adaptive power control algorithm uses intelligent modulation methods to ramp up or ramp down the transmission power level as and when required. By this method, the operational lifetime of the wireless sensor can be extended. As part of the experimental methodology for this paper, two subjects of different age groups have been used. Experimental results show that there is at least a 12% increase in the energy savings using the proposed algorithm.

Reorganization of intruder Using Ad-Hoc Network And RFID

This system is to develop a centralized computer application that needs to identify moving person in a specific area using wireless network. In this paper, we develop a new indoor tracking algorithm using received signal strength. The RFID is able to detect the humans and provide information about the direction of the movement. The gathered information from the node is to be given to the base station for processing. . This application is able to detect and track person, and report direction of the intruder to a central base station. In this system we design nodes through which we are able to track the person. The human intruder is detected using Zigbee.

Distributed Multiple-Access for Smart Grid Home Area Networks: Compressed Sensing With Multiple Antennas

This paper proposes the integration of multiple antenna technologies with compressed sensing algorithms to facilitate wireless multiple-access from smart meters to a central base station in smart grid home area networks. This integration is made possible by new precoding weight designs which utilize the multiple antennas for either achieving multiplexing or providing power-gain. For the multiplexing scheme, we show that the use of multiple antennas can significantly reduce the delay, particularly at high signal-to-noise ratios. For the power-gain scheme, we demonstrate that the use of multiple antennas enhances the performance of the compressed sensing algorithm by reducing the impact of unwanted noise, leading to a lower delay. Finally, we compare our distributed scheme with a carrier sense multiple-access scheme, and show that our scheme achieves a lower average delay for even a small number of transmitting nodes.

Detection of Faulty Measurements in WBANs using Gaussian Mixture Model and Ant Colony

Wireless sensor networks are subject to different types of faults and interferences after their deployment. Abnormal values reported by sensors should be separated from faulty or injected measurements to ensure reliable monitoring operation. The aim of this paper is to propose a lightweight approach for the detection and suppression of faulty measurements in medical wireless sensor networks. The proposed approach is based on the combination of statistical model and machine learning algorithm. The authors begin by collecting physiological data and then they cluster the data collected during the first few minutes using the Gaussian mixture decomposition. They use the resulted labeled data as the input for the Ant Colony algorithm to derive classification rules in the central base station. Afterward, the derived rules are transmitted and installed in each associated sensor to detect abnormal values in distributed manner, and notify anomalies to the base station. Finally, the authors exploit the spatial and temporal correlations between monitored attributes to differentiate between faulty sensor readings and clinical emergency. They evaluate their approach with real and synthetic patient datasets. The experimental results demonstrate that their proposed approach achieves a high rate of detection accuracy for clinical emergency with reduced false alarm rate when compared to robust Mahalanobis distance.

A Scalable, 2.9 mW, 1 Mb/s e-Textiles Body Area Network Transceiver With Remotely-Powered Nodes and Bi-Directional Data Communication

<?Pub Dtl=""?> This paper presents transceivers and a wireless power delivery system for a Body-Area Network (BAN) that uses an e-textiles-based physical layer (PHY) capable of linking a diverse set of sensor nodes monitoring vital signs on the user's body. A central base station in the network controls power delivery and communication resource allotment for every node using a general-purpose on-chip Node Network Interface (NNI). The architecture of the network ensures fault-tolerance, reconfigurability and ease of use through a dual wireless-wireline topology. The nodes are powered at a peak end-to-end efficiency of 1.2% and can transmit measured data at a peak rate of 1 Mb/s. Modulation schemes for communication in both directions have been chosen and a Medium Access and Control (MAC) protocol has been designed and implemented on chip to reduce complexity at the power-constrained nodes, and move it to the base station. While transferring power to a single node at maximum efficiency, the base station consumes 2.9 mW power and the node recovers 34 µW, of which 14 µW is used to power the network interface circuits while the rest can be used to power signal acquisition circuitry. Fabricated in 0.18 µm CMOS technology, the base station and the NNI occupy 2.95 mm 2 and 1.46 mm 2 area, respectively.

Peer-to-peer bichromatic reverse nearest neighbours in mobile ad-hoc networks

The increasing use of mobile communications has raised many issues of decision support and resource allocation. A crucial problem is how to solve queries of Reverse Nearest Neighbour (RNN). An RNN query returns all objects that consider the query object as their nearest neighbour. Existing methods mostly rely on a centralised base station. However, mobile P2P systems offer many benefits, including self-organisation, fault-tolerance and load-balancing. In this study, we propose and evaluate 3 distinct P2P algorithms focusing on bichromatic RNN queries, in which mobile query peers and static objects of interest are of two different categories, based on a time-out mechanism and a boundary polygon around the mobile query peers. The Brute-Force Search Algorithm provides a naive approach to exploit shared information among peers whereas two other Boundary Search Algorithms filter a number of peers involved in query processing. The algorithms are evaluated in the MiXiM simulation framework with both real and synthetic datasets. The results show the practical feasibility of the P2P approach for solving bichromatic RNN queries for mobile networks.

A comprehensive simulation analysis of LTE Discontinuous Reception (DRX)

In an LTE cell, Discontinuous Reception (DRX) allows the central base station to configure User Equipments for periodic wake/sleep cycles, so as to save energy. DRX operations depend on several parameters, which can be tuned to achieve optimal performance with different traffic profiles (i.e., CBR vs. bursty, periodic vs. sporadic, etc.). This work investigates how to configure these parameters and explores the trade-off between power saving, on one side, and per-user QoS, on the other. Unlike previous work, chiefly based on analytical models neglecting key aspects of LTE, our evaluation is carried out via simulation. We use a fully-fledged packet simulator, which includes models of all the protocol stack, the applications and the relevant QoS metrics, and employ factorial analysis to assess the impact of the many simulation factors in a statistically rigorous way. This allows us to analyze a wider spectrum of scenarios, assessing the interplay of the LTE mechanisms and DRX, and to derive configuration guidelines.

Energy-Efficiency based Analysis of Routing Protocols in Mobile Ad-Hoc Networks (MANETs)

mobile MANET (Mobile Ad-hoc Network) is an actively self organizing and self configuring network without the need of any centralized base station. This is a collection of various mobile nodes that is connected through a wireless medium forming rapidly changing topologies in the network. The MANETs are infrastructure less in nature and can be set up anytime, anywhere. In the MANETs, all the nodes are mobile and are battery operated. As because all the nodes in MANETs have limited battery resources and due to node mobility, multi hop routes are used over a changing network environment, so to limit the power consumption, to prolong the network lifetime and to improve the robustness of the system, energy efficient routing protocols are required. The design of efficient routing protocols is a fundamental problem in Mobile Ad-Hoc Network (MANET). Many routing protocols have been proposed in the literature, each one is based on different characteristics and properties in MANETs. Some of these respective protocols have been studied and their performances have been analyzed focusing on aspects like energy consumption, packet delivery fraction, network lifetime etc. In this paper, a performance comparison of the DSR (Dynamic Source Routing), AODV (Ad-Hoc on Demand Distance Vector) and DSDV (Destination Sequenced Distance Vector) routing protocols is evaluated on the basis of energy efficiency metrics by varying number of nodes, number of connections and pause time. Simulations are done using NS-2(version NS- 2.35). It has been verified through extensive simulations, which mostly represents a wide spectrum of network conditions that DSR delivers the better performance and needs smaller energy expenditure as that of algorithms AODV and DSDV but it is observed that DSDV prolongs the network lifetime better than the other two protocols and provides better load balancing capability.

Maximizing Quality of Coverage under Connectivity Constraints in Solar-Powered Active Wireless Sensor Networks

Energy harvesting is a promising solution for reducing network maintenance and the overhead of replacing chemical batteries in sensor networks. In this article, problems related to controlling an active wireless sensor network comprised of nodes powered by both rechargeable batteries and solar energy are investigated. The objective of this control is to maximize the network's Quality of Coverage (QoC), defined as the minimum number of targets that can be covered by the network over a 24-hour period. Assuming a time-varying solar profile, the underlying problem is to optimally control the sensing range of each sensor so as to maximize the QoC. The problem is further constrained by requiring all active sensors to report any sensed data to a centralized base station, making connectivity a key factor in sensor management. Implicit in the solution is the allocation of solar energy during the day to sensing tasks and recharging of the battery so that a minimum coverage is guaranteed at all times. The problem turns out to be a nonlinear optimal control problem of high complexity. By exploiting the particular structure of the problem, we present a novel method for determining near-optimal sensing radii and routing paths as a series of quasiconvex (unimodal) optimization problems. The runtime of the proposed solution is 60X less than the standard optimal control method based on dynamic programming, while the worst-case error is less than 8%. The proposed method is scalable to large networks consisting of hundreds of sensors and targets. Several insights in the design of energy-harvesting networks are provided.

Enhanced AODV Route Discovery and Route Establishment for QOS Provision for Real Time Transmission in MANET

MANET is a temporary connection of mobile nodes via wireless links having no centralized base station. We developed a protocol with an enhanced route discovery mechanism that avoids the pre-transmission delay. When a source node wants to communicate with another node, it broadcast RREQ. EAODV give priority to the source node of real time transmission . When RREQ packet send to neighbor node, for real time transmission it accept route request on priority basis and the drop ratio of packets decreased, then throughput increases by receiving more packets at destination and delivery ratio also increased through these QOS improved.

A novel coverage and connectivity preserving routing protocol for mission-critical wireless sensor networks

Mission-critical wireless sensor networks (WSNs) have been found to be very useful for many military and civil applications such as disaster management, surveillance of battle fields and e-healthcare. Coverage preservation and connectivity are the most essential functions to guarantee quality of service (QoS) in mission-critical WSNs. By optimizing coverage, the deployment strategy would guarantee that optimum area in the sensing field is covered by sensors, as required by various types of mission-critical applications. Whereas by ensuring that the network is connected, it is ensured that the sensed information is transmitted to other nodes and possibly to a centralized base station which makes valuable decisions for the applications. However, a trade-off exists between sensing coverage and network lifetime due to the limited energy supplies of sensor nodes. In this paper, we propose a Coverage and Connectivity Preserving Routing Protocol for mission-critical WSNs (CCPRP) to accommodate connectivity, energy-balance and coverage-preservation for sensor nodes in WSNs that are hierarchically clustered. The energy consumption for radio transmissions and the residual energy over the network are taken into account when the proposed protocol determines an energy-efficient route for a data from elected cluster head to the base station through elected gateway. We define a cost metric to favour nodes with high energy-redundantly covered as better candidates for cluster heads in a way to improve the performance of sensing coverage, reduce communications energy and prolonging the effective network lifetime with optimal data delivery. Furthermore, we propose a novel area coverage protocol called CCPRP-AC for scheduling the sensing activity of sensor nodes that are deployed to sense point-targets in WSN using information coverage. The simulation results demonstrate that the proposed protocol CCPRP is able to increase the duration of the on-duty network and provide up to 124.76% of extra service time with 100% sensing coverage ratio comparing with other existing protocols, and the protocol CCPRP-AC achieves k-coverage of a field, where every point is covered by at least k sensors with a minimum number of sensors.

Mobile UW-ASN framework with RSSI-based protocol for shallow river monitoring

Approximately three-fourths of our planet’s surface is covered by ocean and seas, a continuous body of water that is divided into several oceans and smaller seas. Water conditions determine climate that affects life on Earth. Whereas fresh water in lakes and rivers covers less 1%, its contamination significantly damages ecosystems. Within this research this paper proposes a framework with a custom protocol stack for river monitoring with hybrid network topology. The main goal is to design and implement a framework of distributed network of navigating autonomous underwater vehicles (AUV) and fixed sensors for rivers that will collect monitoring information and transmit data to the central base station. Proposed framework perfectly fits into the latest notion of internet of underwater things architecture and in future it can be utilised not only for shallow river monitoring but also in such extended applications as pipeline surveillance, harbour security and fish farms monitoring.

Fangled Protocol for Black Hole Detection in Ad Hoc Networks

Now a day, security in Mobile Ad hoc Network is very important issue. Due to dynamic topology and mobility of nodes, Mobile Ad hoc Networks are more vulnerable to security attacks than conventional wired and wireless network. Nodes of Mobile Ad hoc Network communicate directly without any central base station. That means in ad hoc network, infrastructure is not required for establishing communication. Therefore attacks in this are very frequent than other networks. In this research paper we are describing black hole attacks which are easy to launch in wireless ad hoc network. Black hole attack is referred to as a node dropping all packets and sending forged routing packets to route packets over itself. Ad hoc networks are vulnerable to different kinds of attacks such as: denial of services, impersonation, and eavesdropping.This paper discusses one of the security problems in ad hoc networks called the black hole problem. It occurs when a malicious node referred as black hole joins the network. The black hole conducts its malicious behaviour during the process of route discovery. For any received REQ, the black hole claims having a route and propagates a faked REP. The source node responds to these faked REPs and sends its data through the received routes. Once the data is received by the black hole, it is dropped instead of being sent to the desired destination.The proposed protocol is built on top of the original AODV. It extends the AODV to include the following functionalities: source node waits for a reliable route; each node has a table in which it adds the addresses of the reliable nodes; REP is overloaded with an extra field to indicate the reliability of the replying node.Â

Colorless Two Different Gigabit Data Access Transmissions Using Optical Double Sideband Suppressed Carrier and Optical Sideband Slicing

A wavelength division multiplexed (WDM) radio over fiber access network architecture, capable of simultaneously transmitting both 63 GHz wireless and 2.5 Gb/s wired data, is proposed in this paper. An optical carrier suppression effect and multiplexing of a 50 GHz spaced arrayed waveguide grating are employed to generate a 63 GHz millimeter-wave signal based on WDM. These techniques allow the proposed scheme to simultaneously transmit both wireless and wired data. For full colorless operation, a reflective semiconductor optical amplifier is used at the central office and base station. Error-free simultaneous transmissions [wired data: bit error rate (BER) of 10-12, wireless data: BER of 10-9] of 2.5 Gb/s wired data and 1.25 Gb/s wireless data are achieved. Various impacts of the downlink transmission on the performance of uplink data are investigated with the proposed scheme.

Analysing and Implementing the Mobility over MANETS using Random Way Point Model

Wireless networks are increasing in popularity with current advances in technology, The architecture of such networks is not based on a centralized base station but on each node which acts as a router and forwards data packets to other nodes in the network. The technologies have driven into new era with the introduction of ad hoc networks and the concept behind the ad hoc networks is it works without the access points. It has features like adaptive, self organizing and decentralized in nature. Due to these specialized features, it has become a popular technology. So, there has been an inevitable need of a good routing protocol in order to establish the connection between the nodes since the mobile nodes can change their topology frequently. The movement of the mobile node is one of the important characteristics because it can affect the performance of the ad hoc network protocol. This paper has analyzed the mobility of the random waypoint model for different routing protocols in mobile ad-hoc network.

In situ image processing capabilities of ARM-based micro-controllers

Dealing with visual data is the key for environmental monitoring tasks in Wireless Multimedia Sensor Networks (WMSNs). Tasks such as object detection, recognition, and/or tracking do require extracting and using the right information from the inherently large amount of visual data. The widely accepted solution of legacy WSNs, transmitting the acquired data to a central base station for further processing, would render a WMSN totally useless because of the unacceptable use of bandwidth and energy. Therefore, we consider the in situ processing as a viable solution for WMSNs. However, processing power and memory capacity restrictions of existing multimedia sensor nodes along with their power consumption are the limiting factors for wide-spread use of in situ processing. Nevertheless, recent technological improvements and introduction of the new ARM cores encourage us to evaluate the image processing capabilities of ARM7/ARM9/ARM11 based micro-controllers for in situ processing in WMSNs. In this work, we first discussed the architectural design differences among the various ARM cores. Then we classified image processing algorithms into three categories. Then, we evaluated the performance of each microcontroller by running a set of basic image processing algorithms necessary for object detection, recognition, and/or tracking. The test results show that ARM11 runs up to 6---30 times faster than ARM9 and ARM7, respectively. Besides, ARM11 consumes up to 5---7 times less energy than ARM9 and ARM7 for the same type of operations.

A Democratic Head Election Strategy for Clustering in Wireless Sensor Network

In recent years a lot of work has been done on Wireless Sensor Network (WSN) as it find its application in many applications including environmental monitoring and military field surveillance. In these applications tiny sensor nodes are deployed across the application regions. Data gathered by the sensor nodes are periodically collected by the base stations. As the nodes are deployed and left unattended for a long time it becomes quite difficult to recharge the node batteries. Several WSN applications require only an aggregate value to be reported to the base station. In this case sensors in different regions of the field can collaborate to aggregate their data and provide more accurate reports about their local regions. This type of data aggregation can reduce the communication overhead in the network and can increase the network life time. In order to support data aggregation through efficient network organization, nodes can be partitioned into a number of small groups called clusters. Each cluster has a coordinator, referred to as cluster head and a number of member nodes. The member nodes report their data to the respective Cluster Heads (CHs). The CHs aggregate the data and send them to the central base station through other CHs. This process improves the network lifetime which is an important metric to evaluate the network performance. In this type of system the challenging issue is to selection of CHs in each cluster along with the cluster head rotation to increase network life time and to reduce the communication overhead among the nodes in a WSN. In our work we have proposed an election algorithm to select the CHs in a democratic fashion by the nodes in the network. The performance of the proposed algorithm has been successfully demonstrated by the simulation of the proposed system.

Performance Analysis of Downlink Multi-Cell OFDMA Systems Based on Potential Game

This paper investigates the subcarrier allocation problem for a downlink multi-cell multiuser OFDMA network using potential game theory. Each player is considered to be a central base station together with all the mobiles distributed within its coverage area. In such a system, co-channel interferences (CCI), if left uncontrolled, could hinder the transmissions and limit the throughputs of the users, especially those near the cell-edge area. Certain remedies, including power control with pricing, did not seem to solve the problem completely. We specifically address this issue from an interference-minimizing approach, where the utility function adopted is meant to minimize the total CCI among players. Under such formulation, we show that the formulated game can be mathematically described by a potential game. Hence, a Nash equilibrium (NE) will be guaranteed for the proposed game and stable solutions can be achieved via myopic gameplays such as the best/better responses. We propose our iterative algorithm for obtaining the NEs and address several performance issues such as fairness for edge-users and the price of anarchy. Numerical results show the improvement in efficiency and fairness using this approach.

Energy Harvesting for Aerospace Structural Health Monitoring Systems

Recent research into damage detection methodologies, embedded sensors, wireless data transmission and energy harvesting in aerospace environments has meant that autonomous structural health monitoring (SHM) systems are becoming a real possibility. The most promising system would utilise wireless sensor nodes that are able to make decisions on damage and communicate this wirelessly to a central base station. Although such a system shows great potential and both passive and active monitoring techniques exist for detecting damage in structures, powering such wireless sensors nodes poses a problem. Two such energy sources that could be harvested in abundance on an aircraft are vibration and thermal gradients. Piezoelectric transducers mounted to the surface of a structure can be utilised to generate power from a dynamic strain whilst thermoelectric generators (TEG) can be used to generate power from thermal gradients. This paper reports on the viability of these two energy sources for powering a wireless SHM system from vibrations ranging from 20 to 400Hz and thermal gradients up to 50°C. Investigations showed that using a single vibrational energy harvester raw power levels of up to 1mW could be generated. Further numerical modelling demonstrated that by optimising the position and orientation of the vibrational harvester greater levels of power could be achieved. However using commercial TEGs average power levels over a flight period between 5 to 30mW could be generated. Both of these energy harvesting techniques show a great potential in powering current wireless SHM systems where depending on the complexity the power requirements range from 1 to 180mW.