Department of Electrical and Electronics Engineering

Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1925

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Start date: 2020Subject: search.filters.subject.Performance analysis

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Now showing 1 - 10 of 20
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    Performance analysis of high voltage gain converters for renewable energy applications
    (BITS PILANI, Pilani campus, 2025) Sharma, Preeti
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    Performance Analysis of Mixed Underwater and Terrestrial OWC Systems Over Foggy Weather
    (IEEE, 2021) Zafaruddin, S.M.
    There has been extensive research on the performance of underwater optical wireless communication (UOWC) mixed with terrestrial OWC (TOWC) over atmospheric turbulence with pointing errors considering deterministic path loss under foggy weather conditions. Recent measurement campaigns provide a probabilistic behavior of the signal attenuation over the foggy channel. In this paper, we analyze the performance of a mixed TOWC-UWOC system by considering random foggy channels with pointing errors for the terrestrial link and lognormal distribution for underwater communication. We apply the decode-and-forward (DF) relaying to integrate the two technologies and analyze the performance of the proposed system by deriving analytical expressions of the outage probability, average SNR, and ergodic rate in terms of channel and system parameters. We use measurement data fitted parameters of the random fog and underwater channel to demonstrate the performance of mixed links under various foggy conditions and characteristics of underwater turbulence. We validate our derived mathematical expressions using numerical analysis and Monte Carlo simulations and demonstrate the performance of the relay-assisted mixed link over different foggy conditions and underwater turbulence.
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    Dual Sensor Impulse Noise Cancellation for Downstream DSL Systems
    (IEEE, 2021-05) Zafaruddin, S.M.
    Impulse noise presents a severe performance bottleneck in multicarrier systems. For digital subscriber lines (DSL), the use of a common-mode (CM) sensor is a viable technique to mitigate the impulse noise that couples into the useful differential-mode (DM) signal. In this paper, we use time and frequency domain approaches to develop algorithms using the joint processing of CM and DM signals and analyze the performance of dual-sensor based interference cancellation schemes for downstream DSL systems. First, we consider the frequency domain approach and analyze the performance of a per-tone impulse noise canceler without requiring an impulse detector. We derive closed-form expressions on the performance of canceler in various interference scenarios in terms of system parameters. Next, we develop a novel per-symbol time-domain impulse noise canceler by simultaneous estimation of the CM2DM transfer function and the CM impulse noise using a limited number of null carriers. The proposed algorithm eliminates the issues of convergence of the per-tone canceler and stationarity of the impulse noise over multiple symbols. Using derived analytical expressions, we show that the proposed canceler effectively mitigates the impulse noise on a per-symbol basis. We also demonstrate the performance of the considered canceler schemes using measurement and simulation results.
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    Performance Analysis of Cooperative Relaying for Multi-Antenna RF Transmissions over THz Wireless Link
    (IEEE, 2022) Zafaruddin, S.M.
    Recent research has focused on single antenna radiofrequency (RF) and terahertz (THz) wireless systems to mix the access link with the backhaul. In this paper, we evaluate the performance of a mixed RF-THz system employing multiple antenna-assisted access point (AP) for the RF link and single-antenna THz transmissions. We employ an equal gain combining (EGC) receiver at the AP and use the fixed-gain amplify and forward (AF) relaying protocol to interface the RF and THz links. We derive analytical expressions for probability density function (PDF) and cumulative distribution function (CDF) of the end-to-end SNR for the considered system assuming independent and non-identically distributed (i.ni.d.) α−μ distribution to model for both RF and THz channels and pointing errors in the THz link. We analyze the system performance using the outage probability, average bit error rate (BER), and ergodic capacity involving bivariate Fox’s H-function. We use the residue method to develop asymptotic analysis using Gamma functions to show the impact of the various channel and system parameters on the outage probability and average BER in the high SNR regime. We use computer simulations to depict the scaling of the performance with an increase in the number of antennas at the AP for signal reception in the access link.
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    Simplified Performance Analysis of OWC System Over Atmospheric Turbulence with Pointing Error
    (IEEE, 2020) Zafaruddin, S.M.
    Optical wireless communication (OWC) is highly vulnerable to the atmospheric turbulence and pointing error. Performance analysis of the OWC system under the combined channel effects of pointing errors and atmospheric turbulence is desirable for its efficient deployment. The widely used Gamma-Gamma statistical model for atmospheric turbulence, which consists of Bessel function, generally leads to complicated analytical expressions. In this paper, we consider the three-parameter exponentiated Weibull model for the atmospheric turbulence to analyze the ergodic rate and average signal-to-noise ratio (SNR) performance of a single-link OWC system. We derive simplified analytical expressions on the performance under the combined effect of atmospheric turbulence and pointing errors in terms of system parameters. We also derive approximate expressions on the performance under the atmospheric turbulence by considering negligible pointing error. In order to evaluate the performance at high SNR, we also develop asymptotic bounds on the average SNR and ergodic rate for the considered system. We demonstrate the tightness of derived expressions through numerical and simulation analysis along with a comparison to the performance obtained using the Gamma-Gamma model.
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    Terahertz Wireless Transmissions with Maximal Ratio Combining over Fluctuating Two-Ray Fading
    (IEEE, 2022) Zafaruddin, S.M.
    Mitigating channel fading and transceiver impairments are desirable for high-speed terahertz (THz) wireless links. This paper analyzes the performance of a multi-antenna THz wireless system by considering the combined effect of pointing errors and fluctuating two-ray (FTR) fading model. We provide a statistical characterization of the maximal ratio combining (MRC) receiver over independent and nonidentical (i.ni.d.) channel conditions in terms of multi-variate Fox’s H by deriving density and distribution functions of the signal-tonoise ratio (SNR) of a single-link THz link using incomplete Gamma function. We develop exact analytical expressions of outage probability, average bit-error-rate (BER), and ergodic capacity for both single-antenna and MRC receivers. We also present the diversity order of the system by deriving asymptotic expressions for outage probability and average BER at high SNR to obtain insights into the system performance. We validate our derived analytical expressions with Monte-Carlo simulations and demonstrate the effect of various system and channel parameters on the performance of single and multi-antenna THz wireless communications.
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    Optical Wireless Transmissions over Multi-layer Underwater Channels with Generalized Gamma Fading
    (IEEE, 2022) Zafaruddin, S.M.
    Underwater optical communication (UWOC) is a potential solution for broadband connectivity in oceans and seas for underwater applications providing high data rate transmission with low latency and high reliability. Recent measurement campaigns suggest generalized Gamma distribution as a viable model for oceanic turbulence. In this paper, we analyze the performance of a UWOC system by modeling the vertical underwater link as a multi-layer cascaded channel, each distributed according to independent but not identically distributed (i.ni.d.) generalized Gamma random variables and considering the zero bore-sight model for pointing errors. We derive analytical expressions for probability density function (PDF) and cumulative distribution function (CDF) for the signal-to-noise ratios (SNR) of the combined channel and develop performance metrics of the considered UWOC system using outage probability, average bit error rate (BER), and ergodic capacity. We also derive the asymptotic expressions for outage probability and average BER to determine the diversity order of the proposed system for a better insight into the system performance. We use Monte-Carlo simulation results to validate our exact and asymptotic expressions and demonstrate the performance of the considered underwater UWOC system using measurement-based parametric data available for turbulent oceanic channels.
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    Reconfigurable Intelligent Surface Empowered Multi-Hop Transmission over Generalized Fading
    (IEEE, 2022) Zafaruddin, S.M.
    The use of multiple reconfigurable intelligent surfaces (RIS) between a source and destination can enhance the performance of wireless communications over severe shadowing environment by creating line-of-sight (LOS) connectivity. This paper analyzes the performance of a multiple RIS empowered multi-hop transmission for a wireless system. We develop an analytical framework to derive statistical results of the signal-to-noise ratio (SNR) of the multi-RIS communication by considering independent and non-identical double generalized gamma (dGG) fading channels in each hop. We analyze the performance of the considered multi-RIS system by deriving exact analytical expressions of the outage probability, average bit-error rate (BER), and ergodic capacity in terms of Fox’s H-function. We present asymptotic analysis and diversity order of the outage probability in the high SNR regime to provide a better insight into the system performance. We use computer simulations to demonstrate the effect of multiple RIS modules, and fading parameters on the RIS-aided multi-hop transmissions for the considered communication system.
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    Unified Performance Assessment of Optical Wireless Communication Over Multi-Layer Underwater Channels
    (IEEE, 2022-10) Zafaruddin, S.M.; Chaubey, Vinod Kumar
    In this paper, we model the multi-layer vertical underwater link as a cascaded channel and unify the performance analysis for the underwater optical communication (UWOC) system using generalized Gamma (GG), exponential GG (EGG), exponentiated Weibull (EW), and Gamma-Gamma ( ΓΓ ) oceanic turbulence models. We derive unified analytical expressions for probability density function (PDF) and cumulative distribution function (CDF) for the signal-to-noise ratios (SNR) considering independent and non-identical (i.ni.d.) turbulent models and zero bore-sight model for pointing errors. We develop performance metrics of the considered UWOC system using outage probability, average bit error rate (BER), and ergodic capacity with asymptotic expressions for outage probability and average BER. We develop the diversity order of the proposed system to provide a better insight into the system performance at a high SNR. We also integrate a terrestrial OWC (TOWC) subjected to the combined effect of generalized Malága atmospheric turbulence, fog-induced random path gain, and pointing errors to communicate with the UWOC link using the fixed-gain amplify-and-forward (AF) relaying. We analyze the performance of the mixed TWOC and multi-layer UWOC system by deriving PDF, CDF, outage probability, and average BER using the bivariate Fox H-function. We use Monte-Carlo simulation results to validate our exact and asymptotic expressions and demonstrate the performance of the considered underwater UWOC system using measurement-based parametric data available for turbulent oceanic channels.
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    Energy Consumption Performance of Opportunistic Device-to-Device Relaying Under Log-Normal Shadowing
    (IEEE, 2021-12) Zafaruddin, S.M.
    Efficient transmission protocols are required to minimize the energy consumption of mobile devices for ubiquitous connectivity in the next-generation of wireless networks. In this article, we analyze the energy consumption performance of a two-hop opportunistic device-select relaying (ODSR) scheme, where a device can either transmit data directly to a base station (BS) or relay the data to a nearby device, which forwards the data to the BS. We select a single device opportunistically from a device-to-device (D2D) network based on the energy required for transmission, including the energy consumed in the circuitry of the devices. By considering the log-normal shadowing as the dominant factor between devices and the BS, and Rayleigh fading in D2D links, we derive analytical bounds and scaling laws on average energy consumption. The derived analytical expressions show that the energy consumption of the ODSR decreases logarithmically with an increase in the number of devices, and achieves near-optimal performance only with a few nearby devices. This is an important design criterion to reduce latency and overhead energy consumption in a relay-assisted large-scale network. We also demonstrate the performance of the ODSR using simulations in realistic scenarios of a wireless network.