Deepthi Chander

E-PULRP: Energy Optimized Path Unaware Layered Routing Protocol for Underwater Sensor Networks

Energy optimized Path Unaware Layered Routing Protocol (E-PULRP) for dense 3D Underwater Sensor Network (UWSN) is proposed and analysed in this paper. In the proposed E-PULRP, sensor nodes report events to a stationary sink node using on the fly routing. E-PULRP consists of a layering phase and communication phase. In the layering phase, a layering structure is presented wherein nodes occupy different layers in the form of concentric shells, around a sink node. The layer widths and transmission energy of nodes in each layer are chosen taking into consideration the probability of successful packet transmission and minimization of overall energy expenditure in packet transmission. During the communication phase, we propose a method to select intermediate relay nodes on the fly, for delivering packets from the source node to sink node. We develop a mathematical framework to analyse the energy optimization achieved by E-PULRP. We further obtain expressions for throughput, delay and derive performance bounds for node densities and packet forwarding probabilities, for given traffic conditions. A comparison is made between the results obtained based on simulations and analytical expressions. The energy efficiency is also demonstrated in comparison with existing routing protocol for underwater sensor networks.

PULRP: Path Unaware Layered Routing Protocol for Underwater Sensor Networks

We propose a path unaware layered routing protocol (PULRP) for dense underwater 3D sensor networks. An uplink transmission is considered, where a set of underwater sensor nodes report events to the sink node. PURLP algorithm consists of two phases. In the first phase (layering phase), a layering structure is presented which is a set of concentric spheres, around a sink node. The radius of the concentric spheres is chosen based on probability of successful packet forwarding as well as packet delivery latency. In the second phase (communication phase), we propose a method to choose the intermediate relay nodes and an on the fly routing algorithm for packet delivery from source node to sink node across the chosen relay nodes. The proposed algorithm, PULRP finds the routing path on the fly and hence it does not require any fixed routing table, localization or time synchronization processes. Our findings show that the proposed algorithm has a considerably better successful packet delivery rate compared to the under water diffusion (UWD) algorithm proposed in the paper by Lee et al. (2007) and Dijkstras shortest path algorithm. In addition the delay involved in PULRP is comparable with that of UWD.

Distributed Detection for Landslide Prediction using Wireless Sensor Network

In this paper we propose a wireless sensor network (WSN) architecture for landslide prediction in the rocky mountain regions of the Konkan Railways. The overall scheme has two major components: (i) Wear leveled, fault tolerant energy efficient routing protocol and (ii) distributed decision on the occurrence or non-occurrence of landslide. In this paper our focus is on statistical modeling of the landslide strain data and subsequent distributed decision algorithm. We simulate pressure variation on rock samples in a testbed at NT-Bombay and measure the corresponding strain. This strain data is modeled using variable mean Gaussian process (VMGP). We examine different distributed decision algorithms and find that the distributed scalar based detection (DSBD) gives as good results as the centralized detection (CD) scheme with respect to probability of missed detection, probability of false alarm, with lesser energy consumption at nodes. Receiver operating characteristic (ROC) curves are presented to compare the relative performance of different schemes. Simulation of CD scheme was also done on a simple mica2 testbed.

Layered data aggregation in cell-phone based wireless sensor networks

The ubiquitous use of mobile phones motivates the idea of dasiaparticipatory sensingpsila with a cell-phone based sensor network. In our work, we consider a layered architecture for a query-based urban monitoring application using mobile phones. The key contribution of the paper is a Data-Aware Layered Waiting (DA-LW) time aggregation protocol in cell-phone based wireless sensor networks. To motivate the DA-LW protocol, we first develop a Cluster-Head (CH) based data aggregation protocol. The performance of the proposed protocols is evaluated in terms of energy, delay and resolution, which are primarily important for the monitoring application. Simulation results demonstrate the overall superiority in performance of the Data-Aware Layered Waiting algorithm over the Cluster-Head based algorithm.

DVD Based Moving Event Localization in Multihop Cellular Sensor Networks

In this paper, we consider moving event localization using data collected from a Multihop Cellular Sensor Network (MCSN). The main contribution of the paper is a novel structure-free Distributed Velocity Dependent (DVD) waiting time based protocol. We compare the performance of the proposed DVD protocol with that of a Centralized approach and the existing Randomized Waiting time (RW) protocol. Simulation results show that DVD exhibits a performance superior to RW with respect to center of event localization error and end-to-end delay. We also present simulation results on the the sensitivity analysis based comparison between DVD, RW and the Centralized scheme.

AdWAS: Adaptive Weighted Aggregation Scheme for Single-hop and Multi-hop Wireless Sensor Network

In the need to conserve communication energy we consider one bit aggregation in wireless sensor network (WSN) in the context of event detection. In this paper we propose a novel Adaptive Weighted Aggregation Scheme (AdWAS) for star as well as tree topology. We compare the performance of the proposed adaptive w eighted aggregation scheme with existing one bit non-adaptive aggregation schemes. In non-adaptive schemes, a slight variation in the topology or performance indices necessitate recalculation of the initial setup. However, in the proposed adaptive scheme we just need to fine tune the weights starting from the previously adapted weights to compensate for any small variation in the topology. Moreover, there is hardly any performance degradation w hen using AdWAS. This clearly makes the adaptive setup more appealing.

Spatio-Temporally Adaptive Waiting Time for Cell Phone Sensor Networks

In cell phone sensor networks (CpSN), sensor-embedded cell phones communicate sensor data using Near Field Communication outlets such as Wi-Fi or Bluetooth. This paper considers a query dissemination application of CpSN, where sensor data belonging to a certain time window [ t s , min , t s , max ] is needed from a region of interest. Existing approaches, such as ADAPT, use adaptive broadcast ranges at the Wireless Access Point (WAP) for query dissemination. This paper proposes the adaptation of waiting time at nodes for energy-efficient query dissemination. The design and analysis of the proposed Spatio-Temporally Adaptive Distributed Velocity Dependent (STA-DVD) waiting time is presented. The STA-DVD protocol is analytically compared with a Spatially Adaptive Distributed Velocity Dependent (SA-DVD) waiting time based protocol. Simulation results show that STA-DVD has a superior querying performance in terms of number of samples procured than SA-DVD, at a slightly higher energy cost. For the case of a Randomized Waiting (RW) time adopted by nodes in ADAPT, the ADAPT-RW protocol has the best querying performance, with significantly high energy costs. STA-DVD has a comparable querying performance with ADAPT-RW, for high residual times and a better performance for low residual times, with significantly low energy dissipation.

Spatio-Temporal Power Adaptive (STPA) Protocol for MCpSN

In our work, we consider a querying application of a Multihop Cell phone Sensor Networks (MCpSN). It requires data to be sensed within a time window and further uploaded at the Querying Access Point within a time deadline. Considering a Random Waypoint distribution of cell phone users, we propose a novel, energy-efficient Spatio-Temporal Power Adaptive (STPA) protocol for this application. STPA is compared to purely spatially/temporally adaptive schemes through simulations.

Distributed velocity-dependent protocol for multihop cellular sensor networks

Cell phones are embedded with sensors form a Cellular Sensor Network which can be used to localize a moving event. The inherent mobility of the application and of the cell phone users warrants distributed structure-free data aggregation and on-the-fly routing. We propose a Distributed Velocity-Dependent (DVD) protocol to localize a moving event using a Multihop Cellular Sensor Network (MCSN). DVD is based on a novel form of connectivity determined by the waiting time of nodes for a Random Waypoint (RWP) distribution of cell phone users. This paper analyzes the time-stationary and spatial distribution of the proposed waiting time to explain the superior event localization and delay performances of DVD over the existing Randomized Waiting (RW) protocol. A sensitivity analysis is also performed to compare the performance of DVD with RW and the existing Centralized approach.

CrowdLoc: Cellular Fingerprinting for Crowds by Crowds

Determining the location of a mobile user is central to several crowd-sensing applications. Using a Global Positioning System is not only power-hungry, but also unavailable in many locations. While there has been work on cellular-based localization, we consider an unexplored opportunity to improve location accuracy by combining cellular information across multiple mobile devices located near each other. For instance, this opportunity may arise in the context of public transport units having multiple travelers. Based on theoretical analysis and an extensive experimental study on several public transportation routes in two cities, we show that combining cellular information across nearby phones considerably improves location accuracy. Combining information across phones is especially useful when a phone has to use another phone’s fingerprint database, in a fingerprinting-based localization scheme. Both the median and 90 percentile errors reduce significantly. The location accuracy also improves irrespective of whether we combine information across phones connected to the same or different cellular operators. Sharing information across phones can raise privacy concerns. To address this, we have developed an id-free broadcast mechanism, using audio as a medium, to share information among mobile phones. We show that such communication can work effectively on smartphones, even in real-life, noisy-road conditions.