Dr.K.Krishna Naik
@iiitk.ac.in
Associate Professor, Electronics and Communication Engineering
Indian Institute of Information Technology Design and Manufacturing Kunrool
RESEARCH, TEACHING, or OTHER INTERESTS
Computer Networks and Communications, Computer Engineering, Multidisciplinary, Information Systems
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Krishna K Naik
Defence Scientific Information and Documentation Centre
Today’s Electronic Warfare (EW) receivers need advanced technology to achieve real-time surveillance operations. Dynamic and intelligent systems are required for UAVs and other airborne applications. The airborne Electronic Warfare systems must be knowledge-based systems, learning from the threat scenario with highly integrated capabilities to detect, react, and adapt to radar threats in real-time. Artificial intelligence is a machine-dependent process, by adapting certain rules and logic supported by human intelligence, AI can be used for cognitive processing. Cognitive signal processing is required for making the system autonomous and dynamic in nature. Military action on radar signatures requires a set of commands to be executed dynamically with the help of the proposed EW system. It is proposed to design and develop a cognitive EW architecture and simulation of machine learning that combines neural network architecture with the help of sine and square waves as input. This paper presents the Cognitive signal processing for EW systems with Neural Network, Recurrent Neural Network (RNN), Machine learning (ML), and Deep learning (DL) techniques with their simulation with sine and square waves.
B. Sathish Nayak, Sidharth Bhonge, K. Krishna Naik, Odelu Ojjela, and Surendra Pal
Defence Scientific Information and Documentation Centre
Satellite-based positioning field of research is growing rapidly as there is an increase in demand for precise position requirements in various civil and commercial applications. There are many errors that affect the GNSS signals while propagation from satellite to receiver, which eventually induces errors in pseudo-range measurements. In order to assess the receiver characteristics for a specific error condition, the real-time signals may not be appropriate, and it is challenging to perform repeated experiments with the same error condition. The advantage of the GNSS simulator is that users can model the different scenarios for any given location on the globe, which are repeatable at any point of time. The conventional hardware simulators are expensive and have few limitations. In this paper, a reconfigurable hybrid simulator is proposed with some advantages over traditional hardware simulators, such as low cost, reconfigurability, and controllability over fundamental parameters. It can be able to record intermediate stage data, which makes it more suitable for the GNSS research field. The proposed multi-GNSS simulator considered implementing IRNSS-L5, IRNSS-S1, and GPS-L1 band signals. A general-purpose computer can perform the necessary calculations for signal generation. The hybrid simulator can be able to generate the digital I/Q data, which can be stored as I/Q data or can be connected to a general-purpose SDR (Software Defined Radio) for RF signal generation (bladeRF in this case). The I/Q data can be used with the software receiver to analyse the receiver performance concerning the specific error. The generated GNSS signals are validated with software and hardware receivers, and the obtained position is observed as expected.
Ajit Singh, K. Krishna Naik, and C. R. Suthikshn Kumar
Springer Science and Business Media LLC
Ajit Singh, K. Krishna Naik, and C.R.S. Kumar
Informa UK Limited
ABSTRACT Orthogonal Frequency Division Multiple Access (OFDMA) is now becoming an impeding rather than a sustainable technology for realizing the vision of 5G due to its tight synchronization, orthogonality constraints, and significant bandwidth wastage due to Cyclic Prefix. To overcome this limitation, several non-orthogonal schemes have been introduced as candidates for upcoming 5G technology for providing flexible, reliable, fair and high-speed multiple access to users and/or devices. A combination of Non-Orthogonal Multiple Access (NOMA) and Universal Filtered Multi-Carrier (UFMC) is found suitable for downlink scenario. We propose NOMA-UFMC-based Radio Access (NOMURA) scheme, which is asynchronous, bandwidth efficient and provides higher throughput. The proposed scheme is non-orthogonal in two aspects: (1) NOMA provides resources to different users via power scaling while utilizing same frequency resources, and (2) UFMC allows for a slight delay in synchronization, hence not strictly compliant with orthogonality requirements. The components of the proposed scheme, namely NOMA and UFMC, are backward compatible with OFDMA ensuring trivial application of Multiple Input Multiple Output and other performance enhancement measures already developed for OFDMA. We provide simulation results benchmarked against OFDMA and Filter Bank Multi-Carrier-Filtered Multi-Tone and show that NOMURA is more apt for flexible bandwidth allocations, active cancellation, higher throughput and provides equivalent Bit Error Rate performance under AWGN and Rayleigh fading conditions.
Sathish Nayak, K. Krishna Naik, and Odelu Ojjela
Springer Singapore
Sathish Nayak B, Krishna Naik K, and Odelu Ojjela
IEEE
In satellite based navigation system the location accuracy depends on how accurately the pseudorange is measured. The pseudorange, the distance from satellite to receiver and is measured by the time taken for the signal to travel from satellite to receiver multiplied by speed of light. There are several factors affecting the measured delay, like ionospheric and tropospheric delays, clock errors, ephemeris error and multipath error, etc. These errors (in terms of delays) are directly reflected in pseudorange error. Among these errors multipath is the type of error which depends on the receiver antenna position. The received signal consists of Line Of Sight (LOS) signal along with reflected signals. The accurate measure of the delay corresponding to LOS is crucial, when the received signal is corrupted with multipath reflected signals. To reduce this error in pseudorange measurements there are several methods in use, starting from simple antenna based methods to sophisticated adaptive filtering based LOS signal estimation methods. The conventional methods follow Early Minus Late delay lock loop approach to measure the code phase by detecting correlation peak of the received signal with locally generated code sequence. Correlator spacing between early and late is limited by the front end bandwidth of the receiver. The advanced multipath mitigation methods use adaptive filtering techniques to estimate the fundamental LOS signal parameters viz delay, amplitude and phase. The approximation of LOS correlation function from the received signal is based on some measurement metrics of the signal. These LOS correlation function estimation based methods are capable of mitigating multipath error in closely spaced multipath scenarios. In this paper the signal model of the received signal, correlation function representation when the three reflected paths present along with the LOS signal and the study of different multipath mitigation methods are discussed.
Sagar Shriram Salwe and Karamtot Krishna Naik
Informa UK Limited
ABSTRACT Internet of Things (IoT) can connect billions of devices and services at anytime, anyplace with diverse applications. Heterogeneous network provides Always Best Connected network between the various technologies. We consider a hybrid network among recent Bluetooth and Wi-Fi technologies to provide the IoT applications. Bluetooth low energy (BLE) works with the minimum amount of power and data rate, sufficient to handle the IoT applications. Wi-Fi Alliance also developed the IEEE 802.11ah which is specifically designed for IoT applications. In this paper, we performed heterogeneous wireless network scenario between the advanced IEEE 802.15.1 (BLE) and IEEE 802.11ah (HaLow) based on Receive Signal Strength as threshold parameter for vertical handover. The simulation results show the Bluetooth versions of Basic Rate, BLE, and Wi-Fi (HaLow) network with the data rate increment after the handover.
Pallavi Ghorpade, Sangram S. More, and K. Krishna Naik
IEEE
This paper illustrates the acoustic transmission of an image from source node to destination node for aerial application. The image data is been transmitted from transmitting node using speaker and received at receiver end using microphone. The signal design and detection is done with the help of MATLAB scripting. The matlab simulation results were found satisfactorily.
Ajit Singh, Sagar S. Salwe, K. Krishna Naik, and C. R. S. Kumar
Springer Science and Business Media LLC
Vanita Pawar, R. Pawar, and Krishna Naik
Elsevier BV
Ajit Singh, K. Krishna Naik, and C.R.S. Kumar
IEEE
Non-Orthogonal Multiple Access (NOMA) is envisioned as promising 5G multiple access technology due to its throughput gain achieved through grouping mobile nodes having substantial difference in channel conditions and capability to serve large number of users simultaneously at same time, frequency, or code, but with different power levels. Furthermore, modifications in OFDM waveform for relaxed synchronization and supporting short burst communications for Internet of Things (IoT) devices has paved the way for Universal Filtered Multi-Carrier (UFMC) waveform. However, a major disadvantage in deployment of Non-Orthogonal UFMC is the high Peak-to-Average-Power-Ratio (PAPR) being comparable to that of OFDMA. As such, additional PAPR reduction techniques are required for reducing the dynamic range of power amplifier deployed in communication system. We take up Power Domain NOMA (PD-NOMA) in which available power is sliced between users and investigate the performance of SC-FDMA for PD-NOMA UFMC systems for PAPR reduction. UFMC is known to provide additional diversity to transmitter in uplink and facilitates relaxed synchronization at the receiver side in downlink scenario. Simulation results show that in flat-fading scenario, BER performance of proposed system is found to be significantly better than OFDM and UFMC. However, BER performance of proposed system in AWGN channel is seen to be traded off as the extent of SC-FDMA precoding increases. Also, increasing pilots per subband leads to increased PAPR with OFDM, UFMC whereas SC-FDMA for PD-NOMA UFMC system shows stagnation and significant comparative reduction in PAPR values.
Sagar Shriram Salwe and Karamtot Krishna Naik
Springer Science and Business Media LLC
Sangram More and K. Krishna Naik
Springer Science and Business Media LLC
Vanita Pawar and Krishna Naik Karamtot
IEEE
This paper proposes multidimensional diversity for the high-velocity channel while enabling pertinent tradeoffs among error performance and complexity. It also analyzes and compares the impact of transmit diversity of information transmission over wireless communication system. The paper considers a high-velocity outdoor system like a vehicular user for which the channel varies too rapidly to be tracked. A blind channel-estimation approach that incorporates a linear prediction and MMSE is proposed, which reduces the effect of any perturbation introduced by linear prediction, noise, and multipath. The comparison results reveal that the proposed method using recursive modified Cholesky (RChol) algorithm is computationally efficient when compared with the existing linear prediction based methods. This algorithm scales down the correlation matrix time averaging and hence unveils a significantly computationally efficient algorithm for the time-domain equalizer.
Sagar Shriram Salwe and Karamtot Krishna Naik
IEEE
Homogeneous wireless network function is based on the horizontal handover between similar wireless technology. Heterogeneous network is formed amongst differing wireless technologies by using the vertical handover scenario. Coexistence between the different wireless standard are based on the interference reduction, access transfer and packet rate arbitration. The reduction in interference technique allows the coexistence of two diverse wireless standards, based on the deterministic and adaptive interference reduction mechanism. In our paper we implemented Normalized Least Mean Square (NLMS) adaptive filter algorithm for excision of the unwanted wideband Wi-Fi signal from the narrowband Bluetooth signal.
Sagar Shriram Salwe and Karamtot Krishna Naik
Institution of Engineering and Technology (IET)
Vertical handover (VHO) plays an important role in providing seamless connectivity between heterogeneous wireless networks. The authors propose VHO mechanism using an image as dynamic discrete data for transmission and received signal strength (RSS)-based switching mechanism. The novelty of work lies in image data used for simulation, RSS calculation using free space propagation model, receive delay calculation and sample-based time series analysis of received data. Results shows that when VHO mechanism is carried out in ISM band operated devices it provides seamless connectivity between diverse communication protocols. Simulation results exhibit the continuous transmission of data and synchronisation of received image data.
Vanita Pawar and Krishna Naik Karamtot
IEEE
In this paper a high performance least square solver is presented which use recursive Cholesky decomposition. Wireless communication systems require solving least square equations in order to obtain taps weights of the FIR filter. It is thus about to develop a fast and efficient algorithm for computation pseudo-inverse matrices. This paper also presents the recursive way to calculate the correlation matrices of receiving signal which is applied to blind channel estimation and for spectrum sensing. The recursive Cholesky algorithm is verified for the Rayleigh channel and the Basis expansion model for known as well as an unknown covariance matrix. The experimental results are very close to analytical results.
Amit Naik and K Krishna Naik
IEEE
Wireless communication technologies change daily with tremendous speed. The first generation consists of analog circuit switching, the second is digital circuit switching (GSM) with 10 Kbps, the third generation is digital packet switching (Wideband CDMA) and now 4G is for very fast speed. A communication unit is said to be flourishing if calls are recognized correctly and efficiently. Handoff is very important for effective use of networks. Switching between GSM and WLAN is implemented with consideration of coupling architecture. Continues data signals are transmitted and received by switching wireless technology from WLAN to GSM and vice versa. Simulation results validate the seamless switching.
Amit Naik and K Krishna Naik
IEEE
An optimized planar antenna for transceiver operating at 1800 MHz (DCS band) is designed and presented. The designed microstrip antenna is used for Digital cellular system operating at the frequency of 1800 MHz with the return loss better than 10 dB.FR4 substrate is used in the design with lesser occupancy of 50*40*3.8mm3. The simulated design of antenna confirms satisfactory output gain and omnidirectional radiation pattern.
Sagar Shriram Salwe and Krishna Naik
IEEE
Wireless network existing in the present generation of communication is homogeneous wireless network, which work in between the same connectivity up to the particular region with specified data rate by standard. We are proposing a heterogeneous wireless network which work in coexistence with other network, which evolve together to communicate over a large region of operation and provide Always Best Connected (ABC) mode and improve the user experience in communication. The vertical handover mechanism proposed is mobile assisted and governed by physical layer handover using received signal strength as a threshold criteria. For simulation purpose we considered Bluetooth and Wi-Fi simulink model as both are working in ISM band. Simulations are performed in Matlab simulink environment.
Ajit Singh, K. Krishna Naik, and C. R. S. Kumar
IEEE
Rapidly increasing user data base and escalating bandwidth demand has compelled Telecom Regulatory Authority of India (TRAI) to open up new spectrum bands for Long Term Evolution (LTE) access lying in TeleVision White Spaces (TVWS) for auction. But rural areas are not likely to respond to the such large bandwidths open to them. The paper proposes implementing Wireless Regional Area Network based on IEEE 802.22 standard which is designed to cater to rural broadband access demands in India. Suggestions are made to grant licenses for WRAN operation in particular geographic region to number of service providers operating on dynamic basis at lower cost for which suitable pricing model is suggested. Basic operation of IEEE 802.22 standard along with its cognitive features required for dynamic spectrum access is presented and a unique scheme based on the same standard to address rural broadband access is proposed.
M Sreenivasa Rao, K Krishna Naik, and K Maheshwara Reddy
Defence Scientific Information and Documentation Centre
In this study, we propose compressive sampling matching pursuit (CoSaMP) algorithm for sub-Nyquist based electronic warfare (EW) receiver system. In compressed sensing (CS) theory time-frequency plane localisation and discretisation into a N×N grid in union of subspaces is established. The train of radar signals are sparse in time and frequency can be under sampled with almost no information loss. The CS theory may be applied to EW digital receivers to reduce sampling rate of analog to digital converter; to improve radar parameter resolution and increase input bandwidth. Simulated an efficient approach for radar signal recovery by CoSaMP algorithm by using a set of various sample and different sparsity level with various radar signals. This approach allows a scalable and flexible recovery process. The method has been satisfied with data in a wide frequency range up to 40 GHz. The simulation shows the feasibility of our method.
Nisheeth Khanna and K. Krishna Naik
IEEE
The deployment of Mobile Adhoc Networks (MANETs) in military/battlefield environment has helped proliferation of wireless voice and data communications services to the users beyond the reach of fixed network connectivity. However, the battery operated mobile nodes are constrained by their battery life, which may be difficult to replace/recharge in hostile battlefield environment, and thus affecting the network lifetime of such a network. Due to the critical operational requirement of such networks, the outage of even a few of the nodes due to power exhaustion might cause disconnect of services in the entire network. The proposed approach aims at increasing the network lifetime of such a MANET, by distributing the routing load among all the nodes within the network. This is achieved by calculating the residual energy of all the nodes in the entire path between the source and the destination, for various paths available, and then comparing and selecting the path which is most optimal in terms of energy efficiency. This approach follows a load balancing approach that avoids power/traffic congested paths and chooses paths that are lightly loaded. This helps in reducing the variance in energy consumption at various nodes due to load distribution and thus eventually increasing the overall network lifetime of the network.
Praveen Kumar and K Krishna Naik
IEEE
Nowadays, in any airborne platform like Fighters, helicopter or a transport aircraft there are thousands of sensors which are used to measure various parameters (temperature, level, pressure, positions and more) and the results are then conveyed through the wires to the on board computers that process them. Therefore, the interconnections of multiple sensors results in a great amount of cables (normally, hundreds of kilometres of cables are used), generating high complexity (both in design and production), high weight and high costs. The aim of this project is to design a WSN on an airborne platform which will then be monitored through a mobile application on ground. Implementing a WSN based system is cost effective as the system is completely wireless leading the way for additional benefits like savings in weight, space, and cost from cabling as compared to a wired sensor network. Monitoring through a mobile application will prevent accidents or damage to the airborne platform by timely alerting the ground based user, who can then take suitable action to avert catastrophe in case of emergency. The proposal would also entail an overall addition for effective performance of manpower with an increased efficiency and a greater awareness of operational and equipment health status of the platform. The mobile App for analysis and monitoring of sensor data can further enhance the performance.