Faculty Publications

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Publications by NITK Faculty

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Subject: search.filters.subject.Low power electronics

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    Common mode feedback circuits for low voltage fully-differential amplifiers
    (World Scientific Publishing Co. Pte Ltd wspc@wspc.com.sg, 2016) Rekha, S.; Laxminidhi, T.
    Continuous time common mode feedback (CMFB) circuits for low voltage, low power applications are proposed. Four circuits are proposed for gate/bulk-driven pseudo-differential transconductors operating on sub-1-V power supply. The circuits are validated for a bulk-driven pseudo-differential transconductor operating on 0.5V in 0.18?m standard CMOS technology. Simulation results reveal that the proposed CMFB circuits offer power efficient solution for setting the output common mode of the transconductors. They also load the transconductor capacitively offering capacitance of about 1fF to tens of femto farads. © 2016 World Scientific Publishing Company.
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    Effective integration of reliable routing mechanism and energy efficient node placement technique for low power IoT networks
    (IGI Global cust@igi-global.com, 2017) Sarwesh, P.; Shet, N.S.V.; Chandrasekaran, K.
    Internet of Things (IoT) is the emerging technology that links physical devices (sensor devices) with cyber systems and allows global sharing of information. In IoT applications, devices are operated by battery power and low power radio links, which are constrained by energy. In this paper, node placement technique and routing mechanism are effectively integrated in single network architecture to prolong the lifetime of IoT network. In proposed network architecture, sensor node and relay node are deployed, sensor nodes are responsible for collecting the environmental data and relay nodes are responsible for data aggregation and path computation. In node placement technique, densities of relay nodes are varied based on traffic area, to prevent energy hole problem. In routing technique, energy efficient and reliable path computation is done to reduce number of re transmissions. To adopt IoT scenario, we included IEEE 802.15.4 PHY/MAC radio and IPv6 packet structure in proposed network architecture. Proposed work result shows, proposed architecture prolongs network lifetime. © © 2017, IGI Global.
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    Application of non-linear Gaussian regression-based adaptive clock synchronization technique for wireless sensor network in agriculture
    (Institute of Electrical and Electronics Engineers Inc., 2018) Upadhyay, D.; Dubey, A.K.; Santhi Thilagam, P.S.
    Efficient and low power utilizing clock synchronization is a challenging task for a wireless-sensor network (WSN). Therefore, it is crucial to design a light weight clock synchronization protocols for these networks. An adaptive clock offset prediction model for WSN is proposed in this paper that exchanges fewer synchronization messages to improve the accuracy and efficiency. Timing information required is collected by setting a small WSN set up to investigate the soil condition to control the irrigation in agriculture. The networks investigate soils moisture, temperature, humidity, and pressure content along with the sensors clock offset. First, the prediction model perceives the existing sensor clock offset to observe the clock characteristics and delay. Then, a Gaussian function is applied for adjusting the parameters weight of the observed value in the prediction model. The system results demonstrate that the proposed adaptive non-linear Gaussian regression synchronization model utilizes 20% less energy as consumed by time sync protocol for sensor-network and reference broadcast synchronization Protocol. It also reduces the synchronization error with respect to root-mean-square error (RMSE) by 24.85% as compared to linear prediction synchronization with RMSE 28.72% in terms of accuracy. © 2001-2012 IEEE.
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    ETRT – Cross layer model for optimizing transmission range of nodes in low power wireless networks – An Internet of Things Perspective
    (Elsevier B.V., 2018) Sarwesh, P.; Shet, N.S.V.; Chandrasekaran, K.
    Internet of Things network is managed by battery operated devices and low power radio links since they are referred to low power networks. In present communication era, many research works are concentrating on low power wireless network. Cross layer design is one of the acclaimed technique that decidedly improves the network performance. In this article, we come up with the cross-layer model that satisfies distinct network requirements and prolongs network lifetime. It integrates physical layer, data link layer (Media Access Control) and network layer in the protocol stack. In our model, a threshold value called ETRT (Expected Transmission Range Threshold) is introduced, which is computed with the help of routing information. Later, MAC based power control technique utilizes the ETRT value and assigns optimum transmission range for every node. The idea at the heels of proposed cross layer model is estimating the capability (ETRT value) of the particular node and assigning the suitable transmission power for every node, based on its capability (ETRT value). Hence, assigning optimum transmission power based on ETRT information prolongs the network lifetime with better reliability and Quality of Service(QoS). From our results, it is noticed that the ETRT based cross layer model performs twice better than the standard model. © 2018 Elsevier B.V.
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    Enhanced mobility aware routing protocol for Low Power and Lossy Networks
    (Springer New York LLC barbara.b.bertram@gsk.com, 2019) Sanshi, S.; Jaidhar, C.D.
    Due to the technological advancement in Low Power and Lossy Networks (LLNs), sensor node mobility becomes a basic requirement for many extensive applications. Routing protocol designed for LLNs must ensure real-time data transmission with minimum power consumption. However, the existing mobility support protocols cannot work efficiently in LLNs as they are unable to adapt to the change in the network topology quickly. Therefore, we propose an Enhanced Routing Protocol for LLNs (ERPL), which updates the Preferred Parent (PP) of the Mobile Node (MN) quickly whenever the MN moves away from the already selected PP. Further, a new objective function that takes the mobility of the node into an account while selecting a PP is proposed. Performance of the ERPL has been evaluated with the varying system and traffic parameters under different topologies similar to most of the real-life networks. The simulation results showed that the proposed ERPL reduced the power consumption, packet overhead, latency and increased the packet delivery ratio as compared to other existing works. © 2017, Springer Science+Business Media, LLC, part of Springer Nature.
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    Fuzzy optimised routing metric with mobility support for RPL
    (Institution of Engineering and Technology JBristow@theiet.org, 2019) Sanshi, S.; Jaidhar, C.D.
    Recently, many Internet of Things (IoT) applications have emerged with mobility as a fundamental requirement. The presence of a mobile node that changes location around the application domain affects the performance of the Routing Protocol for Low Power Lossy Network (RPL) designed for IoT, leading to repeated disruptions that cause data loss and more power dissipation. In this study, a fuzzy optimised routing metric with mobility support (FL-RPL) has been proposed to enhance the performance of the RPL. The fuzzy inference system considers various routing metrics to pick a suitable candidate parent as the preferred parent node to forward the data to the sink node. Further, timer functions have been added to maintain consistent neighbours to support mobility and seamless connectivity. The FL-RPL has been implemented and tested with different parameter settings for a practical scenario. The obtained simulation results clearly demonstrated that the proposed solution increased packet delivery ratio by approximately 12%, and reduced power consumption by 20% compared with the standard RPL. © 2019 The Institution of Engineering and Technology.
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    Ultra-low voltage, power efficient continuoustime filters in 180 nm CMOS technology
    (Institution of Engineering and Technology kvukmirovic@theiet.org, 2019) Rekha, S.; Vasantha, V.M.; Laxminidhi, T.
    The authors propose circuit techniques to implement integrated continuous-time filters for low voltage and low power applications. A fourth order Gm-C filter and a fifth order active-RC Chebyshev filter are used as test vehicles to validate the ideas. Basic building blocks are bulk driven transconductors. Gm-C filter and active-RC filter offer bandwidth of 1 MHz and 750 kHz, respectively while exhibiting a good figure of merit thus ensuring that the designs are energy efficient. Both the filters, fabricated on the same chip in 180 nm CMOS technology, operate on 0.5 V power supply. They offer a dynamic range of 45 and 46.6 dB, respectively. © The Institution of Engineering and Technology 2019.
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    A 1.8 V 8.62 µW Inverter-based Gain-boosted OTA with 109.3 dB dc Gain for SC Circuits
    (Taylor and Francis Ltd, 2019) Kaliyath, Y.; Laxminidhi, T.
    This paper presents a low-power inverter-based gain-boosted operational transconductance amplifier (OTA) for switched capacitor (SC) circuits operating at higher supply voltage (>1 V). The proposed OTA is implemented using UMC 180 nm CMOS technology with a supply voltage of 1.8 V and it offers a high dc gain with a unity gain bandwidth (UGB) suitable for audio applications. All the transistors of the proposed OTA are operated in sub-threshold region to minimize the power consumption. Gain-boosting technique is employed to achieve a higher dc gain. The post-layout simulations demonstrate the robust performance of the proposed OTA, which delivers a high dc gain of 109.3 dB and a UGB of 5.29 MHz at 81° phase margin (PM) with a capacitive load of 2.5 pF for a typical process corner at room temperature (27°C). The proposed OTA draws a quiescent current ((Formula presented.)) of 4.79 µA, resulting in a power consumption of 8.62 µW. © 2019, © 2019 IETE.
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    Enhanced mobility routing protocol for wireless sensor network
    (Springer, 2020) Sanshi, S.; Jaidhar, C.D.
    Recently, the routing protocol for low power and lossy networks (RPL) was standardized and is considered as the default standard for routing over the low power and lossy networks. However, it has not been optimized to work effectively, especially under mobility, and suffers from frequent disconnections that result in packet loss and increased energy consumption. In this paper, an enhanced mobility routing protocol for wireless sensor network (EM-RPL) that incorporates modules to support the mobility of nodes has been proposed. The main goal of the EM-RPL is to increase network reliability and efficiency by selecting a route that is more stable and reduces the frequency of route discovery process. The performance of the proposed EM-RPL has been evaluated in the Contiki-based Cooja simulator and compared with the performance of other protocols that support mobility in the RPL. The simulation results demonstrated that the EM-RPL improves the packet delivery ratio and minimizes power consumption by allowing the mobile nodes to select a more stable path. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
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    Time Constant Enhancement Technique for Low-Frequency Filters
    (Birkhauser, 2020) Rao, G.H.; Rekha, S.
    This paper presents a simple and novel technique to enhance the time constant of a source follower (SF)-based low-pass filter (LPF) for front-end processing of biomedical signals. The proposed technique reduces the capacitor value significantly, which in turn reduces the area of the circuit. Inherent negative feedback and lower number of transistors in this circuit result in good linearity and dynamic range even with low power supply of 0.8 V. A second-order LPF of cutoff frequency (f-3dB) of 100 Hz is designed by cascading the proposed NMOS and PMOS SF LPFs. Cutoff frequency can be tuned linearly from 10 Hz to 1 kHz by varying the bias current and, hence, can be fit into the desired frequency range of different bio-potentials. The filter, designed in UMC 65 nm process, occupies an area of 0.008mm2. It offers a dynamic range of 61.85 dB while consuming a power as low as 8 nW. Figure of merit of the filter is as low as 3.23?10-14J which is better than many other filter designs reported in the literature. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.