SCUMG: Secure Code Update for Multicast Group in Wireless Sensor Networks

Securing code update is essential for military and health care applications. The functionalists of the sensor nodes in military and health monitoring region depend on their environmental conditions. The sensor nodes will be divided into different multi cast groups based on their location. For each multi cast group a different code update will be sent. We have developed a scheme for secure code update for multi-cast groups.

In order to securely communicate the code update for each multi cast group, a key agreement protocol is developed. This protocol provides confidentiality and immediate authentication. The Protocol is implemented on Tiny OS platform, tested using Tossim simulator and evaluated the Performance. SCUMG protocol is resilient to malicious code update by compromised nodes and provides security against various attacks.

Channel Sensitivity of LIFO-Backpressure: Quirks and Improvements

We study the delay performance of backpressure routing algorithms using LIFO schedulers (LIFO-backpressure). We uncover a surprising behavior in which, under certain channel conditions, the average delay of packets is high at low traffic load and decreases as the load in the network increases. We propose and analyze a queueing-theoretic model under which the scheduler can transmit packets only if the queue length meets or exceeds a threshold, and we show that the model analytically bears out the observed phenomenon. Using matrix geometric methods, we derive a numerical solution for the average packet delay in the general case, and, using z-transform techniques, we further provide closed-form solutions for a special case.

Our analysis indicates that when the threshold is fixed (as may happen under lossless channel conditions), the average delay is small at low traffic load and increases with increasing load, as expected. On the other hand, when the threshold fluctuates (as may happen under changing, lossy channel conditions), the average delay may be high at low load and decrease, sometimes substantially, with the traffic load. We corroborate these findings with TOSSIM simulations on different types of networks, using measured channel traces. Further, we propose a replicationbased LIFO-backpressure algorithm (RBL) to improve the delay performance of LIFO-backpressure. Analytical and simulation results show that RBL dramatically reduces the delay of LIFObackpressure at low load, while maintaining high throughput performance at high load.

A Hybrid Multicast Routing for Large Scale Sensor Networks with Holes

In this article, we present RE2MR, the first hybrid multicast routing protocol that builds on the strengths of existing topologybased, hierarchical and geographic multicast solutions, while addressing their limitations. In RE2MR, the multicast path search problem is formulated as the Capacitated Concentrator Location Problem (CCLP) which yields the network topology that minimizes the sum of path lengths from the multicast root to multicast members. Furthermore, its Trajectory-based Lightweight Hole Detection (THLD) discovers deployment area irregularities (i.e., network holes) that affect its solution and autonomously take them into account to generate updated routing paths, and its Energy-efficient Packet Forwarding (EPF) and Multi-level Facility Computation (MFC) reduce computational and communication overheads.

We implement RE2MR in TinyOS and evaluate it extensively using TOSSIM for relatively largescale simulations (400 nodes); we also implement RE2MR on real-hardware and perform experiments on a testbed consisting of 42 TelosB motes. Through the simulations and experiments on real-hardware, we demonstrate that RE2MR reduces the energy consumption by up to 57% and the end-to-end delay by up to 8%, when compared with the state-of-the-art multicast routing protocols.

Mobile agent based secure code update in wireless sensor networks

Most of the sensor nodes are battery powered and energy utilization is one of the important criteria. At the same time Securing code update is very much essential for military, health care and environmental applications. But to send the code updates in a distributed, multihop sensor networks, most of the energy will be consumed in forwarding the packets to next hop sensor nodes. In order to avoid this and save energy consumption at sensor nodes, a small number of mobile agents are used to distribute the code.

Mobile agents traverse along the desired path to disseminate the code. Sensor nodes have to authenticate the mobile agent and at the same time they have to check the integrity of the packets. Mobile agents are more vulnerable for adversaries, hence measures are taken to detect the attacks and rectify them. Secure code update using mobile agents provides confidentiality and immediate authentication. This protocol is implemented on Tiny OS platform, tested using Tossim simulator and evaluated the Performance.

SREE-Tree: self-reorganizing energy-efficient tree topology management in sensor networks

The evolving applications of Information and Communications Technologies (ICT), such as smart cities, often need sustainable data collection networks. We envision the deployment of heterogeneous sensor networks that will allow dynamic self-reorganization of data collection topology, thus coping with unpredictable network dynamics and node addition/ deletion for changing application needs. However, the self-reorganization must also assure network energy efficiency and load balancing, without affecting ongoing data collection. Most of the existing literature either aim at minimizing the maximum load on a sensor node (hence maximizing network lifetime), or attempt to balance the overall load distribution on the nodes. In this work we propose to design a distributed protocol for self-organizing energy-efficient tree management, called SREE-Tree.

Based on the dynamic choice of a design parameter, the in-network self-reorganization of data collection topology can achieve higher network lifetime, yet balancing the loads. In SREE-Tree, starting with an arbitrary tree the nodes periodically apply localized and distributed routines to collaboratively reduce load on the multiple bottleneck nodes (that are likely to deplete energy sooner due to a large amount of carried data flow or low energy availability). The problem of constructing and maintaining optimal data collection tree (Topt) topology that maximizes the network lifetime (L(Topt)) is an NP-Complete problem. We prove that a sensor network running the proposed SREE-Tree protocol is guaranteed to converge to a tree topology (T) with sub-optimal network lifetime. With the help of experiments using standard TinyOS based sensor network simulator TOSSIM, we have validated that SREE-Tree achieves better performance as compared to state-of-the-art solutions, for varying network sizes.

Framework for Secure Code Updates for Wireless Sensor Nodes

In wireless sensor networks securing code update is essential for many crucial military applications. The nodes deployed in border areas in the military region called the border sensor nodes are the more sensitive nodes. The border sensor nodes need to do some special tasks compared to other intermediate sensor nodes. So the code update to be sent to the border nodes will be different from the other intermediate nodes. Thus, the code updates that need to be sent to the border sensor nodes should be highly confidential.

The confidentiality of these code updates cannot be compromised at any cost, hence Key management is also an important issue. A protocol is developed to securely send the code update to the border sensor nodes via intermediate nodes. The Protocol is implemented using necs on TinyOS platform and evaluated the performance.

Simulation based comparative study of MAODV, ODMRP and Gossip protocol

Multicasting is intended for group communication, which supports the dissemination of information from a sender to all the receivers in a group. Mobile wireless Ad Hoc networks are infrastructure less and often used to operate under unattended mode, posing problems like scarcity of bandwidth, short lifetime of the nodes due to power constraints, and dynamic topology caused by the mobility of nodes. Multiple multicasting protocols have been proposed for Ad Hoc networks based on different approaches and some performance simulations are made on numbers of routing protocols.

In this paper, we are comparing three different protocols ODMRP (On-Demand Multicast Routing Protocol), MAODV (Multicast Ad Hoc On-Demand Distance Vector), and Anonymous Gossip (AG) using packet delivery fraction as performance parameter while varying various network parameters such as number of nodes, transmission range and mobility of nodes using the tool GloMoSim. We have also taken average end to end delay as performance metric for analyzing the best protocol for delay sensitive applications. To the best of our knowledge, comparison of these protocols have not yet being done on the parameter chosen by us in the literature. We look at the relative strengths, weaknesses, and applicability of each multicast protocol to diverse situations.

Energy efficient green routing protocol for Internet of Multimedia Things

Internet of Things (IoT) envisions the notion of ubiquitous connectivity of `everything’. However, the current research and development activities have been restricted to scalar sensor data based IoT systems, thus leaving a gap to benefit from services and application enabled by `multimedia things’ or Internet of Multimedia Things (IoMT). Moreover, a crucial issue for Information and Communication Technology (ICT) community is the steer increase in CO2 emissions, which mandates green communication to reduce energy consumption and carbon footprint emissions. Recently, IETF ROLL working group standardized an IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) for resource constrained devices.

RPL builds a tree-like network topology based on some network metric optimization using RPL Objective Functions. Previous RPL implementations for scalar sensor data communication are not feasible for IoMT, since multimedia traffic pose distinct network requirements. The goal of this paper is to design an enhanced version of RPL for IoMT in which the sensed information is essentially provided by the multimedia devices. Our proposed RPL implementation minimizes carbon footprint emissions and energy consumption, along with the incorporation of application specific Quality of Service requirements. To evaluate the performance of the proposed scheme a simulation study is carried out in Cooja simulator for Contiki-OS, which suggests significant gains in terms of energy efficiency and delay.

Functional Constraint Extraction From Register Transfer Level for ATPG

The use of scan test patterns, generated at the gate level with automatic test pattern generation (ATPG) tools in design simulation, was proposed in our previous work to improve verification quality. A drawback of this method is the potential presence of illegal (or unreachable) states (ISEs) causing unwanted behavior and false error detection in the verification process. In this brief, we present a new automated tool that helps overcome this problem. The tool extracts functional constraints at the register transfer level on a VHDL description (it can be easily adapted to any other hardware description language).

The constraints extracted are used in the ATPG process to generate pseudofunctional scan test patterns which avoid the ISEs. The whole verification environment incorporating the proposed tool is presented. Experimental results show the tool impact on the reduction of false error detection in verification. In addition, it shows the verification quality improvements with the proposed environment in terms of coverage, time, and complexity.

Gain flattening of EDFA in C-band using RFA for WDM application

An optimal wideband gain flattened hybrid erbium-doped fiber amplifier/fiber Raman amplifier (EDFA/RFA) with the transmission of sixteen channels in C band ranging from 1528.77 nm to 1554.37 nm in wavelength division multiplexing (WDM) has been modeled to obtain maximum gain uniformity with noise figure <; 6dB. Numerous parameters which are the parameters of the erbium-doped fiber amplifier (EDFA) and the fiber Raman amplifier (RFA) define the gain spectrum of a hybrid EDFA/RFA and an effort has been made to optimize these parameters by simulating the system in optisystem software.

In this paper, we optimize the length of EDFA, and then for different values of pump powers and pump wavelengths of the RFA, the operating gain spectrum and noise figure of the hybrid EDFA/RFA is analyzed. It results in reduction in gain variation to 2.4609 dB with tolerable NF. Another technique employing gain flattening filter is analyzed which results in reduction of gain variation of EDFA to 0.0015 dB. A comparison between the two techniques is made.