BITS Faculty Publications
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Item HRCCTP: A hybrid reliable and congestion control transport protocol for wireless sensor networks(IEEE, 2015) Sharma, Bhupendra KumarIn wireless sensor networks, sensor nodes have extremely restricted power because of hardware constraints. Packet losses and retransmissions effect from congestion enhance latency in the network and diminish delivery ratio and valuable energy and reduce the lifetime of sensor nodes. In this paper, reliable and congestion based transport layer protocol has been proposed which provides an efficient mechanism for achieving reliability and congestion control. During the congestion situation, it focuses to maintain the reliability of information flow to the sink. It uses buffer size to detect congestion and rate adjustment to optimal value is used to mitigate congestion. We present the design and implementation of the proposed protocol and compare it with the existing protocol. Simulation results show a higher packet delivery ratio and throughput with reduced latency and energy loss for proposed protocol in comparison with the existing protocol.Item On Area Coverage Reliability of Mobile Wireless Sensor Networks With Multistate Nodes(IEEE, 2020-05) Chakraborty, SuparnaWireless sensor networks (WSNs) are a special type of infrastructure-less network made up of a large number of tiny sensor nodes with limited energy, processing, and communication capabilities. WSNs have applications in health care, home security, environment monitoring, etc., with research challenges in energy efficiency, network lifetime, and network reliability. One of the major research challenges lies in providing application-specific coverage of the region of interest and reliable transmission of the gathered data to the mobile sink in the presence of multi-state sensor nodes. To quantify such a capability, this paper proposes a quantitative measure, called Area Coverage Reliability (ACR) for WSNs. ACR brings together WSN reliability, area coverage, energy efficiency, mobility of data collector or sink, random duty cycle of nodes, and multi-state nature of sensor nodes under a common umbrella. This paper proposes a Monte Carlo simulation approach that utilizes an energy matrix to evaluate the effect of energy-depleted nodes and energy-oriented data transfer capability on ACR. The energy matrix reflects the residual energy of sensors, the energy required to transmit data to the neighboring nodes, connectivity, and the multi-state nature of the sensors. The proposed approach is illustrated through a series of random examples. The ACR information allows the network designers to achieve a better understanding of the impact of random duty cycle, node energy, node/link reliability, and randomly deployed sensors on reliability.Item Integrated Cooperative Synchronization for Wireless Sensor Networks(IEEE, 2019-06) Chalapathi, G.S.S.A precise decentralized clock synchronization method, referred to as integrated cooperative synchronization (ICS) is proposed in this letter. ICS is a delay compensating method that relies on mean-field message passing, where the measurement phase is integrated into the message passing phase. By selecting an extended factorization of the underlying joint a-posteriori distribution of the clock parameters and an appropriate message scheduling for link initialization, ICS is conceptually much simpler than conventional message-passing methods while achieving similar accuracy and reduced computational complexity. Moreover, it has only slightly higher implementation requirements compared to less accurate consensus methods.Item E-SATS: An Efficient and Simple Time Synchronization Protocol for Cluster- Based Wireless Sensor Networks(IEEE, 2019) Chamola, Vinay; Chalapathi, G.S.S.Over the past decade, the Internet of Things (IoT) has attracted enormous interest from the research community and industry. IoT requires a synergy of various technologies, and wireless sensor networks (WSNs) are poised to play a critical role in many IoT applications like weather monitoring, smart-grids, smart-city and so on. The synchronization of local clocks of the WSN nodes is essential in many network functionalities, and thus a time synchronization protocol is required in WSNs. Although several synchronization protocols have been proposed for WSNs, most of them are simulation-based works. They make many assumptions at a high-abstraction level and do not consider the conditions of the line-of-sight (LOS) in the network. These factors significantly affect the performance of these protocols. Thus, conclusive experimental proof of the effectiveness of these protocols for different LOS conditions is required. In this direction, this paper proposes a time synchronization protocol called efficient and simple algorithm for time synchronization (E-SATS) for a cluster-based WSN. In this paper, E-SATS has been tested on a large-sized WSN testbed in different LOS scenarios and compared with the existing state-of-the-art protocols. E-SATS outperformed existing protocols by achieving up to six times better accuracy as compared to existing protocols with significantly lesser computations and energy consumption.Item Investigation on the aspect ratio of conducting superstrates in deciding its function as a gain enhancer/suppressor for wideband slot antenna(ACM Digital Library, 2022-09) Kumar, A. V. PraveenThis paper presents an investigation on the effect of the aspect ratio (AR or width-to-length ratio) of a conducting sheet for radiation control i.e., gain enhancement or suppression, leading to useful applications for wireless communication. A wideband slot antenna working in 6–8.5 GHz band is adopted as the basic antenna. It is found that for the sheet AR < 1, the boresight (θ = 0°) gain in the entire band is enhanced, while for AR > 1, boresight gain suppression is achieved. For an optimum AR such that AR(enhancement) = 1/AR(suppression), the same sheet can serve the above dual purposes according to its azimuthal orientation with respect to the slot. For ϕ = 0° orientation with respect to the slot, the sheet acts as a gain enhancer, while for ϕ = 90° orientation, it suppresses the radiation, both in θ = 0°. Practically, the sheet orientation can be easily controlled manually. Antenna measurements demonstrate an impedance band of 6–8.66 GHz with bidirectional radiation pattern, and 1.11 dBi boresight gain at 7.25 GHz. A conducting sheet of size 1.45λ0 × 0.29λ0 where λ0 is the free-space wavelength at 7.25 GHz, is loaded above the slot which improves the boresight gain by 5.77 dB, and when rotated by ϕ = 90°, suppresses the gain by 8.78 dB, both relative to the original slot antenna.Item 3G Mobile Networks: Architecture, Protocols and Procedures(McGraw Hill, 2004) Narang, NishitIn India, the mobile subscriber baser is increasing at a phenomenal rate. After the successful adoption of Second Generation (2G) Technology GSM and 2.5G Technology GPRS, the industry is now rapidly moving towards Third Generation (3G) Networks. The book, written by two young engineers, touches almost every imaginable aspect of a 3G Network, spanning across topics such as: • UMTS Network Architecture (including Access Network and Core Network), • Protocols (including RRC, NBAP, RANAP, MM/GMM, MAP and GTP), • Procedures (including UTRAN Procedures, Mobility Management, Call/Session handling and Security Management), and • Services (including Supplementary Services and Value-added Services). Also the book covers topics like IP Multimedia Sub-system (IMS) and SIGTRAN. Besides these, the book includes the status of deployment of 3G UMTS Networks across the world and provides a brief introduction to 4G Networks setting the tone for future advancements. With this coverage, the book would serve the needs of telecom engineers and students.Item Implementation of multi-hop time synchronization on miniature test-bed setup of underwater acoustic sensor network(IEEE, 2014) Gudino, Lucy J.Time synchronization is an important part of any distributed networked embedded system. It is essentially the process of achieving and maintaining common time base among all network nodes of the system. This task is quite challenging for the systems or applications like sensor networks, since these systems are highly resource constrained, yet need to process time-sensitive data in collaborative manner. Though many protocols have been suggested for terrestrial sensor networks (RSB, TPSN, FTSP and LTS) and they perform reasonably well, very few protocols (THSL, Tri-message) have been suggested for the high-latency underwater acoustic networks, since achieving time-synchronization for high-latency networks is even more challenging issue. Here we describe a very simple extension and implementation of Tri-message time synchronization protocol for multi-hop Underwater Acoustic Sensor Network (UASN) on the miniature test-bed setup.Item Performance analysis of rectangular, triangular and E-shaped microstrip patch antenna arrays for wireless sensor networks(IEEE, 2014) Gudino, Lucy J.Generally wireless sensor nodes have been using omni-directional antennas to broadcast data. But these antennas are not very efficient as they suffer from poor spatial reuse, high collisions, decreased throughput and are not energy efficient. Usage of directional antennas which radiate in a particular direction is more efficient as it can lead to significant energy savings. They reduce beamwidth by concentrating power in a certain direction. In this paper, the performance of conventional omni-directional quarter wave monopole antenna, rectangular patch antenna array, triangular patch antenna array and E-shaped patch antenna array are compared. The antenna arrays have been designed, simulated and tested. The antenna arrays designed are fabricated and then are mounted on a sensor node. The performance analysis in terms of power consumption, received signal strength and packet delivery ratio is performed for individual antenna arraysItem Review of protocol stack development of Underwater Acoustic Sensor Network (UASN)(IEEE, 2015) Gudino, Lucy J.Underwater Acoustic Sensor Network (UASN) has become increasingly important, with numerous applications emerging from various areas such as commercial, environmental-research and defense. This paper provides a comprehensive view of current state-of-the-art in UASN by analyzing the research done by various communities. It briefly states the basics of underwater acoustic communication and cites advances in research and development at various layers of networking modules, namely physical, data link, network, transport and application layer. It also covers interesting new concepts of cross-layer protocol stack design along with requirement of network management protocols pertaining to UASN. Finally, various hardware, software tools and test-beds developed by prominent universities/research organizations are described. We also briefly provide information about the test-bed set-up at our laboratory at BITS -Pilani K K Birla Goa Campus.Item High bandwidth data streaming in Sensor Network with mobile nodes(IEEE, 2015) Gudino, Lucy J.Streaming multimedia data in WSN is a challenge due to constraints such as bandwidth, energy and delay. Moreover, it is not economical to have multimedia sensors integrated with static nodes in the field. In this paper, we propose the use of mobile sensor nodes, which are equipped with multimedia sensors for event monitoring. These mobile entities are capable of streaming high bandwidth data by splitting it and routing the packet to the base station using Frequency Division Multiplexer (FDM) modules. This is done with the support of multi-channel disjoint path routing aided with the static WSN deployed. Experiments were done using MicaZ and TelosB motes to evaluate the performance with the help of our custom designed robotic vehicle. The paper adopts a node disjoint multi-path routing protocol for establishing parallel paths between the sender and the receiver. Experimental results indicate that the proposed approach can be effectively used for transferring high bandwidth data to the base station.