Electrical Engineering

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Shiv Nadar University

We consider a fast fading AWGN multiple-access channel (MAC) with full receiver CSI and distributed CSI at the transmitters. The objective is to evaluate the ergodic sum-capacity of this decentralized model, under identical average powers and channel statistics across users. While an optimal water-filling solution can be found for centralized MACs with full CSI at all terminals, such an explicit solution is not considered feasible in distributed CSI models. Our main contribution is an upper-bound on the ergodic sum-capacity when each transmitter is aware only of its own fading coefficients. Interestingly, our techniques also suggest an appropriate lower bound. These bounds are shown to be very close to each other, suggesting the tight nature of the results.

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(SoE) School of Engineering

IEEE Communications Letters

On the Ergodic Sum-Capacity of Decentralized Multiple Access Channels

As per energy efficiency of a photovoltaic (PV) system is concerned, partial shading is an important issue. Under partial shading condition, the modules of a PV array receive different levels of solar irradiation, so the power generation of a PV system decreases. The power-voltage characteristic of a partially shaded PV array contains multiple local maxima, and the global maximum power point is one of them. The losses in a PV array depend on the shading pattern and the physical location of shaded modules. This paper presents the Futoshiki puzzle pattern for the arrangement of the modules of a PV array under partial shading condition, ensuring the enhancement of the power generation with respect to totally crossed tired (TCT) structure. In this method, the physical locations of modules in a TCT structure PV array are rearranged without changing the electrical connection of the modules. A comparison between the power generation in TCT and Futoshiki puzzle pattern configuration is presented. It is demonstrated that the power generated by a PV array in the Futoshiki configuration method is enhanced, and mismatch loss (ML) is minimized under different shading patterns by theoretical, simulation, and experimental results. © 2013 IEEE.

IEEE Journal of Emerging and Selected Topics in Power Electronics

Maximizing the Power Generation of a Partially Shaded PV Array

The modules of a PV array receive different intensity of solar irradiation under partial shading condition and hence mismatch losses occurs between the modules. Multiple local maxima exist in the power-voltage characteristics of a PV array and out of multiple local maxima one of them is a global maximum power point (GMPP). This paper presents a new approach to distribute the shading effect over the entire array to reduce the mismatch losses, and enhance the power output of a PV array. In this approach, the physical position of the modules in the Total Cross Tied (TCT) configuration are arranged, without changing the electrical connection of the modules, and also the arrangement of the modules in the TCT configuration is done in such a way that, the shading effect is distributed over the entire array, and hence it reduces the multiple local maxima in power-voltage characteristics of a PV array. Thus the tracking of GMPP in the present approach is simpler. In this paper, the output power of a PV array estimated theoretically and by MATLAB simulation for the TCT and the proposed configuration is compared. It is investigated that, the power generation of a PV array with proposed configuration is improved compared to the TCT configuration under different shading patterns. © 2015 IEEE.

2015 IEEE Power, Communication and Information Technology Conference, PCITC 2015 - Proceedings

A novel approach to extract maximum power from partially shaded PV array

IEEE Transactions on Antennas and Propagation

Comments on 'Theoretical Modeling of a Photoconductive Antenna in a Terahertz Pulsed System'

Suppression of interference from narrowband frequency signals play vital role in many signal processing and communication applications. A transform based method for suppression of narrow band interference in a biomedical signal is proposed. As a specific example Electrocardiogram (ECG) is considered for the analysis. ECG is one of the widely used biomedical signal. ECG signal is often contaminated with baseline wander noise, powerline interference (PLI) and artifacts (bioelectric signals), which complicates the processing of raw ECG signal. This work proposes an approach using Ramanujan periodic transform for reducing PLI and is tested on a subject data from MIT-BIH Arrhythmia database. A sum (E) of Euclidean error per block (ei) is used as measure to quantify the suppression capability of RPT and notch filter based methods. The transformation is performed for different lengths (N), namely 36, 72, 108, 144, 180. Every doubling of N-points results in 50\% reduction in error (E). © 2016 IEEE.

Fulltext

2016 International Conference on Signal Processing and Communication, ICSC 2016

Removal of narrowband interference (PLI in ECG signal) using Ramanujan periodic transform (RPT)

3G/4G wireless systems employed multiple antennas at both the transmitter and receiver offered significant gains over single-antenna systems. MassiveMIMO (MM) is one of the 5G technologies, which supports to increase the demand for high speed data, capacity, energy efficiency and spectral efficiency. It is known that space-time multiplexing and/or coding offer attractive means of combating fading and increases the capacity in a multi-antenna communication. In this paper, MM downlink scenario is considered. Performance analysis using conventional precoders like Matched Filter (MF), Zero Forcing (ZF), Regularized Beamforming (RBF) and Minimum Mean Square Error (MMSE) with Singular Value Decomposition (SVD) based balanced equalizer are studied in spatio-temporal environment. Signal to Interference Ratio (SINR) and Bit-Error Rate (BER) are used as performance measures. Monte-Carlo simulations are carried out to compute BER and SINR in MATLAB. © 2016 IEEE.

Performance analysis of linear precoders and SVD in downlink MassiveMIMO Frequency selective channels

With the Moore's law drawing in a saturation limit closer for our current technologies in the semiconductor field, the need for efficient technologies better than the present majorly in terms of energy, speed and storage is growing loud every day. Unexpectedly, the key to this solution comes from the past. Memristor thus became the pioneers for opening of such a possibility. A linear ion drift model of memristor was realized along with a memristor based imply logic gate. The analysis were then carried on various parameters affecting its characteristics such as excitation frequency, drift ion mobility, resistances, state function, electrode size and choice of electrode material. This paper presents a theoretical approach to deal with the understanding of parameters making a memristor and controlling it as a switch and also to identify various issues related to its physical realization. © 2015 IEEE.

Proceedings of the 2015 39th National Systems Conference, NSC 2015

Parametric analysis of memristive switching mechanism

This paper proposes a novel Active Antenna (AA) has capability of frequency switching. The passive antenna with rectangular slot and frequency splitter is used to design the proposed AA. Two separate networks are designed at two separate frequencies and integrated with three port rectangular slot antenna. PIN Diode switches are used to switch between two networks for achieving frequency switching. The proposed antenna can be used for WLAN applications. © 2015 IEEE.

Proceedings of the 2015 IEEE 4th Asia-Pacific Conference on Antennas and Propagation, APCAP 2015

Frequency switchable active antenna

Bandwidth pressure on Ethernet has increased recently because of 3G, 4G, Wi-Fi standards applied to smart phones, tablets, Internet protocol television, social media, gaming etc. Due to above network industries are forced to standardize 100, 400 gigabit Ethernet speeds presently and Terabit Ethernet speeds in near future. According to Moore's law the network bandwidth is doubling every 18 months, and computer bandwidth is doubling every 24 months. This roadmap directs network industry that global network will need 10 Terabit Ethernet by 2020. Such bandwidth achievements are possible either by developing very high speed switches and routers which of course are very costly now, however, significant optical parallelization can provide a low cost solution in present situation. Demand is increasing for more number of PCs, tablets, and smart phones with HD video display day-by-day. Wired entertainment gadgets need complex cabling. To meet above requirements and to avoid complex cabling next generation wireless area networks(WLAN) standards like IEEE802.11ac/ax and 802.11ad can provide very high speed, reliability, and quality. Very high data rates can be obtained using wide frequency bands, high speed processors, and multi-input multi-output antennas. Very high attenuation because of using wide frequency band can be reduced by beam forming using large array of antennas. It results in high reliability at very high speed and wide range. This paper discusses next generation Gigabit Wi-Fi along with wired backhaul with 10, 100, and 400 Gigabit Ethernet extending to Terabit Ethernet which is expected to be available by 2020. © 2016 IEEE.

Recent trends in next generation terabit Ethernet and gigabit wireless local area network

This paper presents complete simulation, modeling and control of threephase grid connected solar Photo Voltaic (PV) module including evaluation of various power quality issues. All the steps involved in complete simulation of three-phase grid connected PV module are presented and discussed in detail. Perturb and Observe (P&O) method has been used for Maximum Power Point Tracking (MPPT). In the proposed model DC bus voltage control, harmonic mitigation and power factor control are discussed as power quality issues. The simulation results are shown in the graphical waveforms and are performed in MATLAB using SIMULINK environment and PSB toolboxes. Copyright © 2016 Institute of Advanced Engineering and Science. All rights reserved.