Imran Tasadduq

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Papers by Imran Tasadduq

CPM-GFDM: A Novel Combination of Continuous Phase Modulation and Generalized Frequency Division Multiplexing for Wireless Communication

Applied sciences, Jan 7, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more

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Pilots based LSE Channel Estimation for Underwater Acoustic OFDM Communication

2020 Global Conference on Wireless and Optical Technologies (GCWOT)

Underwater acoustic (UWA) communication techniques have gained popularity for wireless communicat... more Underwater acoustic (UWA) communication techniques have gained popularity for wireless communication in shallow and deep seas. Orthogonal frequency division multiplexing (OFDM) has established to be a reliable multicarrier modulation method for a UWA communication for fending-off inter symbol interference (ISI). Since the UWA channel happens to be frequency selective in nature because of having multipath signals as a result of transmitted signals bouncing off the sea floor and/or the surface, equalization techniques must be utilized to counter the effect of fading. Therefore, we propose a least-squares error (LSE) based channel estimation technique using pilot subcarriers for UWA OFDM. Simulation results using a Rician fading based underwater channel model show that a reasonable number for the pilots is one-fourth of the number of sub-carriers. Any further increase in the number of pilots does not improve error performance. Moreover, error performance degrades as the energy of the pilots is increased.

Coded-GFDM for Reliable Communication in Underwater Acoustic Channels

Sensors

The performance of the coded generalized frequency division multiplexing (GFDM) transceiver has b... more The performance of the coded generalized frequency division multiplexing (GFDM) transceiver has been evaluated in a shallow underwater acoustic channel (UAC). Acoustic transmission is the scheme of choice for communication in UAC since radio waves suffer from absorption and light waves scatter. Although orthogonal frequency division multiplexing (OFDM) has found its ground for multicarrier acoustic underwater communication, it suffers from high peak to average power ratio (PAPR) and out of band (OOB) emissions. We propose a coded-GFDM based multicarrier system since GFDM has a higher spectral efficiency compared to a traditional OFDM system. In doing so, we assess two block codes, namely Bose, Chaudari, and Hocquenghem (BCH) codes, Reed-Solomon (RS) codes, and several convolutional codes. We present the error performances of these codes when used with GFDM. Furthermore, we evaluate the performance of the proposed system using two equalizers: Matched Filter (MF) and Zero-Forcing (ZF)...

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Pilot-Assisted OFDM for Underwater Acoustic Communication

Journal of Marine Science and Engineering

Multicarrier techniques have made it possible to wirelessly transmit data at higher rates for und... more Multicarrier techniques have made it possible to wirelessly transmit data at higher rates for underwater acoustic (UWA) communication. Several multicarrier techniques have been explored in the past for wireless data transmission. OFDM is known to fight off inter-symbol interference due to the orthogonality of its subcarriers. However, due to time variations, OFDM suffers from intercarrier interference. As the UWA channel is both a time and frequency variant, channel estimation becomes complex. We propose a pilot-based channel estimation technique and explore two equalizers for improving the error performance of an OFDM-based UWA system. Both the equalizers employ pilot subcarriers to estimate the UWA channel. One equalizer is a least squares (LS) equalizer and the other is a zero forcing (ZF) equalizer. Using computer simulations, it is observed that, for an acceptable error performance, the number of pilots should be one-fourth the number of subcarriers. Moreover, if the energy of ...

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Intelligent Decision Support in Automating ABET Accreditation Processes: A Conceptual Framework

MPRA Paper, Aug 5, 2021

Ciphered BCH Codes for PAPR Reduction in the OFDM in Underwater Acoustic Channels

Journal of Marine Science and Engineering, 2022

We propose an effective, low complexity and multifaceted scheme for peak-to-average power ratio (... more We propose an effective, low complexity and multifaceted scheme for peak-to-average power ratio (PAPR) reduction in the orthogonal frequency division multiplexing (OFDM) system for underwater acoustic (UWA) channels. In UWA OFDM systems, PAPR reduction is a challenging task due to low bandwidth availability along with computational and power limitations. The proposed scheme takes advantage of XOR ciphering and generates ciphered Bose–Chaudhuri–Hocquenghem (BCH) codes that have low PAPR. This scheme is based upon an algorithm that computes several keys offline, such that when the BCH codes are XOR-ciphered with these keys, it lowers the PAPR of BCH-encoded signals. The subsequent low PAPR modified BCH codes produced using the chosen keys are used in transmission. This technique is ideal for UWA systems as it does not require additional computational power at the transceiver during live transmission. The advantage of the proposed scheme is threefold. First, it reduces the PAPR; second...

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Linear Equalization Techniques for Underwater Acoustic OFDM Communication

2020 Global Conference on Wireless and Optical Technologies (GCWOT), 2020

Multicarrier acoustic communication has enabled wireless underwater transmission at higher data r... more Multicarrier acoustic communication has enabled wireless underwater transmission at higher data rates. Several multicarrier modulation systems have been explored in the past for data transmission. Orthogonal frequency division multiplexing (OFDM) fights-off inter-symbol-interference due to orthogonality of the carriers. However, it is susceptible to time variations which introduces inter-carrier-interference. Being double selective, the underwater acoustic (UWA) channel is both time and frequency variant. Time variations and multipath fading makes it a complex channel to estimate. In this paper, we explore linear frequency domain equalization techniques available for radio OFDM systems and compare their performance for a shallow underwater acoustic channel. The underwater channel model used is based on Rician shadowed distribution with Doppler shifts. We compare the performance of a linear equalizer with pilot estimated channel against a zero-forcing equalizer where the channel is assumed to be known. Results collected through Monte Carlo simulations show that for a 128-subcarrier OFDM system and a transmitter-receiver separation of 800 m, a gain of almost 7dB is obtained at a BER of 10−3 when a zero-forcing equalizer is used. Moreover, when the subcarriers are increased to 256, this gain almost doubles. In conclusion, the zero-forcing equalizer outperforms the LS equalizer for an underwater acoustic channel.

eCOOL: An Expert System based Approach to Designing Effective Assessments for Course Outcomes and Learning

Transylvanian Review, 2017

Effective and objective assessments of learning outcomes is a key activity in any teaching and le... more Effective and objective assessments of learning outcomes is a key activity in any teaching and learning enterprise. An assessment usually comprises a set of questions designed to test the course learning outcomes. Given an available pool of such questions of various types, assessment design reduces to the selection of a set of suitable questions that satisfies instructor’s preferences. The existence of a large number of possible assessment questions for a given course as well as the multiplicity of preferences render the manual selection of suitable assessment questions not only quite cumbersome but also time-intensive exercise. This paper solves this cumbersome and time-consuming problem of decision support and automation by an appropriate design of an Expert System (ES) through a web-based cloud implementation. It also introduces the idea of a relevance score for the selected questions to help the instructor choose the best one. A case study of an undergraduate course in hydraulic...

Flexible OFDM Transceiver for Underwater Acoustic Channel: Modeling, Implementation and Parameter Tuning

Wireless Personal Communications, 2020

Acoustic signals are a first choice in underwater communication since sound waves face very low a... more Acoustic signals are a first choice in underwater communication since sound waves face very low attenuation in water compared to radio frequency (RF). However, the tendency of receiver to detect multipath signals (due to signals bouncing off surface or the bottom) induces large delay spreads and thus strong channel frequency selectivity. Additionally, rapid spatial and temporal variations in underwater acoustic (UWA) channel makes it hostile for communication systems based on single carrier modulation. Multicarrier modulation techniques, on the other hand, can greatly improve bandwidth utilization and help deal with time dispersal effects. Orthogonal frequency division multiplexing (OFDM) is a proven multicarrier communication system having capabilities to cope with frequency selectivity and delay spreads effectively. OFDM has started to get attention for being a simpler alternative to high complexity and high maintenance single carrier systems in UWA communication systems. This work proposes a Matlab model of an OFDM transceiver along with UWA channel characterization based on Rician shadowed fading model as it perfectly characterizes the way in which a shallow UWA channel behaves. Eventually, the proposed design allows implementation of various OFDM modulation methods and to perform Monte Carlo simulations for bit error rate comparisons together with the ability to tune multiple UWA channel parameters.

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CPM-OFDM Performance over Underwater Acoustic Channels

Journal of Marine Science and Engineering, 2021

We propose and evaluate the performance of a continuous phase modulation based orthogonal frequen... more We propose and evaluate the performance of a continuous phase modulation based orthogonal frequency division multiplexing (CPM-OFDM) transceiver for underwater acoustic communication (UAC). In the proposed technique, the mapper in traditional OFDM is replaced by CPM while a realistic model of underwater channel is employed. Bit error rate (BER) as well as peak to average power ratio (PAPR) performance of the proposed scheme is evaluated using Monte-Carlo simulations. The error performance observed clearly establishes the superiority of CPM-OFDM over traditional OFDM schemes. Specifically, a value of 7/16 or 9/16 for the modulation index gives the best error performance. Furthermore, the error performance of the proposed scheme is within acceptable values up to a transmitter–receiver distance of 1.5 km. Additionally, the PAPR performance of the proposed scheme suggests that like other OFDM schemes, a PAPR reduction scheme is mandatory for acceptable PAPR performance of CPM-OFDM.

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Monitoring Pollution and Air Quality of Pedestrian and Automotive Tunnels in the City of Makkah

2020 Industrial & Systems Engineering Conference (ISEC), 2020

Millions of Muslims annually gather in the holy city of Makkah for annual pilgrimage (HAJJ) and u... more Millions of Muslims annually gather in the holy city of Makkah for annual pilgrimage (HAJJ) and use pedestrian and automotive tunnels to move from one place to another. These tunnels generally use open-loop air circulation systems to maintain air impurities inside the tunnel within acceptable limits. Due to overcrowding and congestion, the amount of time pilgrims spend crossing the tunnel grows drastically, revealing people to hazardous vehicular emissions like volatile organic compounds (VOCs), Sulphur oxides, carbon oxides (CO and CO2) together with fine dust (PM10) and high humidity levels. Moreover, an accident or a ventilation breakdown can expose pedestrians and open vehicles/motorcyclists to high levels of harmful gases. This study presents a monitoring and control system employing internet of things (IoT) to monitor air quality and pollution of long tunnels with predictive analysis and data analytics-based reporting for municipal authorities. Specialized sensors are deployed at predetermined locations in a tunnel together with base-station nodes. These sensor nodes upload collected data to the cloud which is then stored and processed for generating reports and for advising actions to be taken, queries and alert mechanisms. This system controls tunnel aeration and ventilation systems based on some set-points for several pollutants. It alerts the tunnel users via e-notice boards when air pollutants reach alarming levels. Furthermore, the system recommends countermeasures needed to be taken like evacuation information and emergency exits. It is also able to detect fire hazards, smoke, ventilation breakdown and accidents, alerting the authorities to take actions without human involvement.

Towards Multicarrier Waveforms Beyond OFDM: Performance Analysis of GFDM Modulation for Underwater Acoustic Channels

IEEE Access, 2020

In this paper, we assess the performance of a generalized frequency division multiplexing (GFDM) ... more In this paper, we assess the performance of a generalized frequency division multiplexing (GFDM) transceiver for underwater acoustic high data-rate transmission. We also present a comprehensive overview of the work done in the field of next generation multicarrier techniques beyond orthogonal frequency division multiplexing (OFDM) for underwater acoustic (UWA) channels. Since very little work has been done in determining the feasibility of acoustic GFDM, we evaluate the performance of proposed GFDM transceiver in terms of spectral efficiency, peak to average power ratio, error rates and complexity using simulations. We employ two types of receivers-matched filter and zero forcing and evaluate their performances for several system configurations. Results presented show that the zero forcing receiver outperforms the matched filter receiver at high SNR values for almost all the configurations; exceptions being the cases where 1 st and 4 th Xia pulse shapes are employed with higher values of the roll off factor. We also compare the performance of the proposed GFDM transceiver with that of OFDM and show that GFDM outperforms OFDM by almost 4 dB for a symbol error rate of 10 −2. It is concluded that while GFDM is computationally more demanding than OFDM, it is still an appealing technique for future UWA communications due to its higher spectral efficiency, flexibility, and better error performance.

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Automated Generation of Course Improvement Plans Using Expert System

International Journal of Quality Assurance in Engineering and Technology Education, 2017

To satisfy ABET's continuous improvement criterion, an instructor, teaching a course suggests... more To satisfy ABET's continuous improvement criterion, an instructor, teaching a course suggests, at the end of the course, an improvement plan to be implemented when the same course is taught next time. Preparation of such a course improvement plan may be mandatory if a pre-specified target level of students' learning is not attained. Since, manual preparation of a course improvement plan is difficult, an idea of generating it using an expert system is presented. The objective is to make the task of improvement plan preparation easier and enjoyable. The proposed expert system has a set of remedies and a set of rules in a data base. A web-based interface queries the instructor about teaching and assessment tools used in the course. The inference engine selects the most appropriate remedy based on instructor's preferences. A cloud implementation of the expert system has been used to test it for a course.

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Obtaining ABET Student Outcome Satisfaction from Course Learning Outcome Data Using Fuzzy Logic

EURASIA Journal of Mathematics, Science and Technology Education, 2017

One of the approaches for obtaining the satisfaction data for ABET "Student Outcomes" (SOs) is to... more One of the approaches for obtaining the satisfaction data for ABET "Student Outcomes" (SOs) is to transform Course Learning Outcomes (CLOs) satisfaction data obtained through assessment of CLOs to SO satisfaction data. Considering the fuzzy nature of metrics of CLOs and SOs, a Fuzzy Logic algorithm has been proposed to extract SO satisfaction data from the CLO satisfaction data for any given course. The membership functions for the fuzzy variables namely CLOs, SOs and CLO-SO relationship have been defined with an implementable procedure to suit the problem. A set of 24 rules form the rule base of the fuzzy logic algorithm. The algorithm has been implemented and tested in MATLAB. An application example of a real-world problem has been presented.

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Assessment Design Through an Expert System and Its Application to a Course of Hydraulics

Proceedings of the Canadian Engineering Education Association, 2017

An assessment consists of questions addressing the required learning outcomes of a course. If a p... more An assessment consists of questions addressing the required learning outcomes of a course. If a pool of questions of various types is made available then assessment design reduces to selection of questions, one by one, from the pool. Since the number of possible questions for a course may be quite large, and several preferences have to be matched, manual selection of a suitable question is not possible. This paper presents an enhanced implementation of a previously presented idea of a methodology for assessment design with an application to a course of Hydraulics with an initial pool of 1,000 questions. Each question is tagged with a set of attributes. The rules are generated by the expert system itself. The idea of a score of relevance has been introduced. The enhanced implementation displays a set of questions with their relevance scores rather than a single question to let the instructor choose from them. An instance of MS SQL Server at Azure database is used for the web-based cl...

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Viterbi Detection of OFDM-CPM Signals

ABSTRACT

Automated Knowledge Discovery in Facility Layout Planning

This paper proposes a novel methodology for facilities layout planning and optimization in which ... more This paper proposes a novel methodology for facilities layout planning and optimization in which fitness evaluation of layout alternatives is done in an automated manner using an artificial neural network trained to user preferences. The intrinsically uncertain, unstructured, and often tacit nature of facilities layout design preferences and constraints necessitates the use of domain experts in the fitness evaluation of layout alternatives. However, unavailability of domain experts in a timely or economical fashion highlights the need for resorting to the use of automation in this important area. To test the key novel component of the proposed approach, a variety of artificial neural networks are trained on a large data set containing both qualitative and quantitative fitness of layout alternatives and subjective ranking by a domain expert utilizing the knowledge of the application domain. Simulation results strongly support the viability of the proposed concept. Such an automated a...

Hussain 2013, Tasadduq, Ahmad - - On the Contribution of Power Variance in PAPR Reduction for OFDM Signals - IJAACS

Viterbi Decoding of Ofdm-CPM Signals

Recently, a new class of Orthogonal Frequency Division Multiplexing–Continuous Phase Modulation (... more Recently, a new class of Orthogonal Frequency Division Multiplexing–Continuous Phase Modulation (OFDM–CPM) signals that out performs conventional OFDM–PSK signals was introduced. In these signals, binary data sequence is mapped to complex symbols using the concept of correlated phase states of a CPM signal. While optimum and suboptimum,minimum,error probability algorithms have been employed,to arrive at this superiority, in this paper

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A novel adaptive boundary search algorithm for solving facility layout problems

We examine the (dis)incentive effects created by the respective tax systems to invest in human ca... more We examine the (dis)incentive effects created by the respective tax systems to invest in human capital in Atlantic Canada and compare this to a select group of provinces from the rest of Canada. While findings show a steady decline in effective tax rates through the years, thereby creating an incentive effect to invest in post-secondary education, disproportionately higher rate gap differentials in the Atlantic Provinces, on average, combined with negative comparative statics reveal a somewhat different undertone. The counterproductive nature of the competing policies effectively nullifies any status quo argument for education or tax policy in the Atlantic Provinces, when compared to their brethren. The graduate retention rebate provides some solace to the narrative in helping to alleviate early tax burdens and equalize returns, but is difficult to claim effectiveness in assuaging any monetary windfall associated with migration. * Collins would like to acknowledge the support of the CRS-SSHRC institutional research grant at St. Francis Xavier University in helping to complete this research.

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