Sajjad Ali Memon - Academia.edu (original) (raw)
Papers by Sajjad Ali Memon
International Journal of Advanced Computer Science and Applications, 2020
In wireless communication, the radio spectrum is a very rare and precious resource that has curre... more In wireless communication, the radio spectrum is a very rare and precious resource that has currently become a major problem to efficiently exploit the underutilized band of the static allocated licensed band. Recently, the cognitive radio (CR) has emerged as a promising technology to overcome the spectrum crisis, in which, the licensed band can be utilized by the unlicensed user until and unless it does not affect the transmission of the licensed band. In this paper, the spectrum occupancy of three bands i.e. GSM 900, 1800 and 2100 bands have been measured through spectrum analyzer in the indoor and outdoor environment. The measured results of all the three bands have been calculated through MATLAB against the power spectral density versus frequency plots. Results have shown that the majority of the licensed band is underutilized. Therefore, the CR can play a pivotal role to efficiently utilize the unused spectrum and to overcome the cellular wireless spectrum crisis in Pakistan. The second part of this paper deals with the emerging concept of network sharing among mobile operators and its impacts on cost. Network sharing become the standard among mobile operators worldwide and so in Pakistan. Capital (CAPEX) as well as operational (OPEX) expenditure and rapid advancement in technology encouraged all operators to go for sharing business models. In Pakistan, all four mobile operators Jazz, Telenor, Zong, and Ufone are actively adopting this model to maintain EBITDA (earnings before interest, taxes, depreciation, and amortization). Mainly there are two types of network sharing, Passive infrastructure sharing, and active resource sharing. Passive network sharing is widely used in Pakistan among operators.
International Journal of Advanced Computer Science and Applications, 2018
The massive multiple-input-multiple-output (MIMO) is a key enabling technology for the 5G cellula... more The massive multiple-input-multiple-output (MIMO) is a key enabling technology for the 5G cellular communication systems. In massive MIMO (M-MIMO) systems few hundred numbers of antennas are deployed at each base station (BS) to serve a relatively small number of single-antenna terminals with multiuser, providing higher data rate and lower latency. In this paper, an M-MIMO communication system with a large number of BS antennas with zero-forcing beamforming is proposed for the improved spectral efficiency performance of the system. The zero forcing beamforming technique is used to overcome the interference that limits the spectral efficiency of M-MIMO communication systems. The simulation results authenticate the improvement in the spectral efficiency of M-MIMO system. The spectral efficiency value using zero-forcing beamforming is near to the spectral efficiency value with the nointerference scenario.
IET Communications, 2017
In massive multiple-input multiple-output (M-MIMO) systems, the base station (BS) estimates the d... more In massive multiple-input multiple-output (M-MIMO) systems, the base station (BS) estimates the downlink and uplink channels using the uplink pilot training in conjunction with channel reciprocity property of time division duplex (TDD) operation. However, this channel estimation is contaminated due to the use of non-orthogonal pilot sequences for the uplink training in neighbouring cells that results in inter-cell interference. This study proposes an effective pilot contamination elimination scheme along with zero forcing precoding for multi-cell TDD M-MIMO systems. In the proposed scheme, each BS is assigned with a specific orthogonal variable spreading factor (OVSF) code row and a set of Zadoff-Chu (ZC) sequences are used for uplink pilot training. Then, the set of ZC sequences is multiplied element-wise at each BS with its OVSF code row to generate the orthogonality among the pilot sequences across the neighbouring cells. The proposed method can promise uncontaminated channel estimation and interference free downlink transmission without requiring the knowledge of the channels' second-order statistics and without increasing the training overhead by a factor equal to the number of interfering cells. The simulation results authenticate the effectiveness and superiority of the proposed scheme over other schemes.
International Journal of Advanced Computer Science and Applications, 2018
This proposed antenna model and progressing the investigation of an inset fed wideband circular s... more This proposed antenna model and progressing the investigation of an inset fed wideband circular slotted patch antenna is suitable for 5.2 GHz satellite C-band applications. A circularly shaped slot has been chosen to be etched on diminutive square patch (4.4cm*5.64cm) of the inset feed antenna. The object of this work is to develop an efficient and inexpensive transducer system to facilitate its compatibility with monolithic microwave integrated circuits; expenses are minimized for its fabrication and trail low profile for C-band satellite links. This paper focuses on the circular profile of the microstrip patch antenna intended for the proficient gain to enhance the performance of the satellite communication. The return loss of-21.79dB with the directivity 8.22dB and gain of 8.17dB have been estimated. The efficiency of 97% with VSWR of 1.22 compensates each other with better simulation results.
International Journal of Advanced Computer Science and Applications, 2018
Computed tomography angiography (CTA) has turned non-invasive diagnosis of cardiovascular anomali... more Computed tomography angiography (CTA) has turned non-invasive diagnosis of cardiovascular anomalies into a reality as state-of-the-art imaging equipment is capable of recording sub-millimeter details. Based on high intensity, the calcified plaques are easily identified in cardiac CTA; however, low density based non-calcified plaque detection has been a challenging problem in recent years. We propose an efficient method in this work for automated detection of the non-calcified plaques using discrete radial profiles. The plaque detection is accomplished using support vector machine to differentiate abnormal coronary segments. We investigated a total of 32 CTA volumes and the detection mean accuracy of 84.6% was achieved, which is in-line with the reported literature.
The <strong>Urdu-Sindhi Speech Emotion Corpus</strong> is a dataset collected at Mehr... more The <strong>Urdu-Sindhi Speech Emotion Corpus</strong> is a dataset collected at Mehran University of Engineering & Technology, Pakistan by a research team led by Dr. Zafi Sherhan Syed and Dr. Sajjad Ali Memon. The dataset consists on 1,435 audio recordings in total for seven types of emotions which include anger, disgust, happiness, neutral, sarcasm, sadness, and surprise in two low-resource languages of South Asia, that is Urdu and Sindhi. Due to ethical restrictions we cannot release audio recordings at the moment and instead release five feature sets from the OpenSmile toolkit. Please note that we will endeavour to compute any features for you locally and send those features back to you. If this interests you, please contact Dr. Zafi Syed at zafisherhan.shah@faculty.muet.edu.pk
Proceedings of the 2nd International Conference on Communication and Information Processing - ICCIP '16, 2016
In this paper, the performance of massive multiple-input-multiple-output (M-MIMO) with an infinit... more In this paper, the performance of massive multiple-input-multiple-output (M-MIMO) with an infinite number of the base station (BS) antennas is studied. The performance of such systems is only limited by the pilot contamination, which is a negative effect of reusing uplink pilot sequences in the neighboring cells. The channel estimates obtained in the presence of pilot contamination is contaminated, which results in inter-cell interference in the downlink data transmission. This paper shows the severity of pilot contamination in the multi-cell scenario and proposes the implementation of distinct orthogonal variable spreading factor code at each BS to mitigate the pilot contamination in the time-division duplex (TDD) multi-cell M-MIMO systems. The performance of the uplink and downlink sum rates of the proposed scheme is compared with those of the time-shifted pilot scheme for an infinite number of BS antennas. The simulation results show that the proposed scheme outperformed time-shifted pilot scheme, which shows the effectiveness and validity of the proposed scheme.
2019 2nd International Conference on Computing, Mathematics and Engineering Technologies (iCoMET), 2019
various advantages such as: easy to configure, low weight and low cost make microstrip patch ante... more various advantages such as: easy to configure, low weight and low cost make microstrip patch antenna (MPA) the first choice for wireless communication system. The structure of the patch antenna consists of dielectric material in between radiating patch and ground plan. In this paper we present the comparative performance analysis of 4 different shaped antennas. The shapes taken into consider are E, T, H and F. The antenna is designed to operate at is 2.4 GHz. The results of different antenna parameters such as return loss VSWR, radiation pattern, gain and directivity are analyzed on different frequency bands. The E-shaped patch antenna is found much better than the others with overall gain of 7.2 dB at 2.4 GHz. Which is suitable for RFID reader application. Simulation is done using High Frequency Structure Simulator (HFSS) antenna simulation tool.
International Journal of Advanced Computer Science and Applications, 2020
Parkinson's disease is a serious neurological impairment which adversely affects the quality of l... more Parkinson's disease is a serious neurological impairment which adversely affects the quality of life in individuals. While there currently does not exist any cure for this disease, it is well known that early diagnosis can be used to improve the quality of life of affected individuals through various types of therapy. Speech based screening of Parkinson's disease is an active area of research intending to offer a non-invasive and passive tool for clinicians to monitor changes in voice that arise due to Parkinson's disease. Whereas traditional methods for speech based identification rely on domain-knowledge based hand-crafted features, in this paper, we investigate the efficacy of and propose the deep acoustic embeddings for identification of Parkinsonian speech. To this end, we conduct several experiments to benchmark deep acoustic embeddings against handcrafted features for differentiating between speech from individuals with Parkinson's disease and those who are healthy. We report that deep acoustic embeddings consistently perform better than domain-knowledge features. We also report on the usefulness of decision-level fusion for improving the classification performance of a model trained on these embeddings.
Mehran University Research Journal of Engineering and Technology, 2017
Multicarrier transmission technique has become a prominent transmission technique in high-speed w... more Multicarrier transmission technique has become a prominent transmission technique in high-speed wireless communication systems. It is due to its frequency diversity,small inter-symbol interference in the multipath fading channel, simple equalizer structure, and high bandwidth efficiency. Nevertheless, in thetime domain, multicarrier transmission signal has high PAPR (Peak-to-Average Power Ratio) thatinterprets to low power amplifier efficiencies. To decrease the PAPR, a CCSLM (Convolutional Code Selective Mapping) scheme for multicarrier transmission with a high number of subcarriers is proposed in this paper. Proposed scheme is based on SLM method and employs interleaver and convolutional coding. Related works on the PAPR reduction have considered either 128 or 256 number of subcarriers. However, PAPR of multicarrier transmission signal will increase as a number of subcarriers increases. The proposed method achieves significant PAPR reduction for ahigher number of subcarriers as well as better power amplifier efficiency. Simulation outcomes validate the usefulness of projected scheme.
January 2019, 2019
Accurate segmentation of anatomical organs in medical images is a complex task due to wide inter-... more Accurate segmentation of anatomical organs in medical images is a complex task due to wide inter-patient variability and several acquisition dependent artefacts. Moreover, image noise, low contrast and intensity inhomogeneity in medical data further amplifies the challenge. In this work, we propose an effective yet simple algorithm based on composite energy metric for precise detection of object boundaries. A number of methods have been proposed in literature for image segmentation; however, these methods employ individual characteristics of image including gradient, regional intensity or texture map. Segmentation based on individual featres often fail for complex images, especially for medical imagery. Accordingly, we propose that the segmentation quality can be improved by integrating local and global image features in the curve evolution. This work employs the classic snake model aka active contour model; however, the curve evolution force has been updated. In contast to the conv...
International Journal of Advanced Computer Science and Applications, 2018
Wireless body area networks are being widely used due to the increase in the use of wireless netw... more Wireless body area networks are being widely used due to the increase in the use of wireless networks and various electrical devices. A Wearable Patch antenna is used for enhancement of various applications for WBAN. In this paper, a low profile wearable microstrip patch antenna is designed and suggested for constant observation of human vital signs such as blood pressure, pulse rate and body temperature using wireless body area network (WBAN) technology. The operating frequency of the antenna is taken as 2.45 GHz which lies in industrial, scientific and medical (ISM) frequency band. Polyester textile fabric with a relative permittivity of 1.44 and thickness of 2.85 mm is used as a substrate material. The proposed antenna is designed to achieve better return loss, VSWR, gain and low value of specific absorption rate (SAR) as compare to other existing wearable antenna. The achieved antenna return loss at 2.45 GHz is about-10.52 dB and gain of 7.81 dB. The VSWR value achieved at 2.45 GHz is 1.84, which is good in terms of good impedance matching. Other antenna field parameters like 2D and 3D gain, radiation pattern, and SAR value have been calculated. High-Frequency Structure Simulator (HFSS) is used to design and simulate the proposed antenna.
International Journal of Advanced Computer Science and Applications, 2018
International Journal of Advanced Computer Science and Applications, 2018
The performance of co-time co-frequency full duplex (CCDF) communication systems is limited by th... more The performance of co-time co-frequency full duplex (CCDF) communication systems is limited by the selfinterference (SI), which is the result of using the same frequency for transmission and reception. However, current communication systems use separate frequencies for transmission and reception, respectively. Therefore, SI is an important issue to be fixed for future-generation systems. As the radio frequency (RF) spectrum is very scared and a CCDF system has the potential to reduce the current spectrum use by half. In this paper, a CCDF communication system is modeled and a combination of RF and digital cancellations is used to mitigate the SI. The simulation results reveal that the proposed combination of RF and digital cancellation achieve the bit-errorrate of 10-11 at an interference-to-signal ratio of 10 dB, which is satisfying value for CCDF communication. The achieved efficiency of the proposed system is 13 bits/sec/Hz at a signal-tonoise ratio of 50 dB. The antenna separation of 35 dB is considered for the proposed model to keep the data loss as minimum as possible. The performance can be improved further by increasing digital-to-analog converter bits but with added complexity.
International Journal of Information and Electronics Engineering, 2015
The multi-carrier transmission signal in MC-CDMA has a high Peak-to-Mean Envelope Power Ratio (PM... more The multi-carrier transmission signal in MC-CDMA has a high Peak-to-Mean Envelope Power Ratio (PMEPR) which results in nonlinear distortion and system performance degradation. To reduce PMEPR, a pre-interleaver and error control coding based selective mapping method is proposed in this paper. This method generates 2 n sequences of the original data sequence via adding n PMEPR control bits to the original data followed by an interleaver and error control code to make original data more random. The covolutional codes, cyclic codes and low density parity check (LDPC) codes are used as error control codes. The proposed method achieves significant PMEPR reduction and avoids the need of side information transmission. The simulation results reveal the validity of proposed method. Index Terms-MC-CDMA, peak to average power ratio (PAPR), high power amplifier (HPA), selective mapping.
European Transactions on Telecommunications, 2006
In this study, we propose to apply interleavers as a mapping function of selected mapping (SLM) t... more In this study, we propose to apply interleavers as a mapping function of selected mapping (SLM) to reduce peak-to-average power ratio (PAPR) of multi-carrier code division multiple access (MC-CDMA) signals. Additionally, a new method is proposed to send information about selected interleaver without explicit side information. The proposed method employs a scramble code and pilot symbols sent through pilot channel. The SLM with pseudo-random interleavers enables MC-CDMA signal transmitter to obtain the same PAPR reduction ability as SLM with random phase rotation, that is conventional SLM with the best phase rotation way. We confirm that the receivers can detect selected interleavers without degradation of bit error rate by the proposed interleaver estimation method. Copyright # 2006 AEIT.
Journal of Communications, 2017
Massive MIMO has been acknowledged as a promising technology to counter the demand for higher dat... more Massive MIMO has been acknowledged as a promising technology to counter the demand for higher data capacity for wireless networks in 2020 and beyond. However, each Base Station (BS) requires good enough knowledge of Channel State Information (CSI) on both the uplink and the downlink as massive MIMO relies on spatial multiplexing. In Time Division Duplex (TDD) massive MIMO systems, this CSI is acquired using channel reciprocity. However, the use of nonorthogonal uplink pilot sequence due to limited coherence time leads to pilot contamination in TDD massive MIMO systems that results in inter-cell interference in the downlink data transmission. This paper proposes a design of orthogonal uplink pilot sequences for multi-cell TDD massive MIMO systems. We propose to use Zadoff-Chu Pilot Sequences (ZCPS) and eliminate pilot contamination during channel estimation process. In the proposed design, each BS is assigned with a specific orthogonal code and the set of ZCPS is multiplied element-wise at each BS with BS-specific orthogonal code to generate orthogonality among pilot sequences across neighboring cells. The proposed design eliminates pilot contamination during channel estimation process thus achieves significant sum-rate gains as verified by the simulation results.
International Journal of Wireless and Microwave Technologies
One of the key issues of wireless communication networks is the spectrum crisis, and studies note... more One of the key issues of wireless communication networks is the spectrum crisis, and studies noted that static licensed bands are in the under-utilization stage. Recently Cognitive Radio Network facilitates a solution to minimize the spectrum crisis in which unlicensed users can utilize the licensed spectrum without transmission interference. To achieve this task we used Machine Learning techniques for analyzing spectrum occupancy which is an efficient method to analyze spectrum occupancy and provides high accuracy. Supervised machine learning algorithms namely Logistic regression, K nearest neighbor, and Naive Bayes are used to classify a given frequency band. In this paper we collect spectrum samples of GSM 900, 1800, and 2100 bands using Rohde & Schwarz FSH6 Handheld Spectrum Analyzer for developing a dataset, using that dataset we trained the classifiers and analyze their classification performance accuracy. Results have shown the best performance on the validation and testing partition for various Unweighted Average Recall (UAR) of each classifier. Here the Logistic Regression classifier learns the best representation from their feature vector. This research is helpful to measure the spectrum occupancy of different static allocated licensed bands for 24/7. This will give better ideas about spectrum utilization, future spectrum allocation and comfort to serve more users in the limited spectrum. The occupancy measurements of current allocated spectrums can not only provide a convincing basis for making future spectrum allocation policies, but also provide technical support for the development of new communication technologies.
To document the sustained virological response (SVR) in rapid virological responders (RVR) of gen... more To document the sustained virological response (SVR) in rapid virological responders (RVR) of genotype-3 chronic hepatitis C with standard interferon (SdIF).
Objective: To determine the frequency of acute HCV infection after needle stick injury and its tr... more Objective: To determine the frequency of acute HCV infection after needle stick injury and its treatment outcome. Methodology: Patients with HCV positive needle stick injury and reporting within 72 hours of incident were selected. Co-infections with HBV, HDV, HIV, hematological disorders and depression were excluded. Anti-HCV was done at presentation and those testing positive were excluded. HCV RNA was done after two weeks or anti-HCV after six weeks of incident. Those testing positive were kept under observation for 16 weeks for spontaneous resolution. After this period HCV RNA and Genotype were done and therapy with Peg-interferon was started. Rapid, early and sustained virological responses were checked. Results: Two hundred eight patients with HCV positive needle stick injury were selected, 10 (4.8%) developed acute HCV infection out of them one (10%) had spontaneous recovery during the observation period of 16 weeks. seven (77.8%) achieved rapid virological response and eight (88.9%) achieved sustained virological response. Conclusions: Acute HCV is an uncommon disease to diagnose; it has favorable response to therapy if initiated early after a strict surveillance of patients for 8-16 weeks.
International Journal of Advanced Computer Science and Applications, 2020
In wireless communication, the radio spectrum is a very rare and precious resource that has curre... more In wireless communication, the radio spectrum is a very rare and precious resource that has currently become a major problem to efficiently exploit the underutilized band of the static allocated licensed band. Recently, the cognitive radio (CR) has emerged as a promising technology to overcome the spectrum crisis, in which, the licensed band can be utilized by the unlicensed user until and unless it does not affect the transmission of the licensed band. In this paper, the spectrum occupancy of three bands i.e. GSM 900, 1800 and 2100 bands have been measured through spectrum analyzer in the indoor and outdoor environment. The measured results of all the three bands have been calculated through MATLAB against the power spectral density versus frequency plots. Results have shown that the majority of the licensed band is underutilized. Therefore, the CR can play a pivotal role to efficiently utilize the unused spectrum and to overcome the cellular wireless spectrum crisis in Pakistan. The second part of this paper deals with the emerging concept of network sharing among mobile operators and its impacts on cost. Network sharing become the standard among mobile operators worldwide and so in Pakistan. Capital (CAPEX) as well as operational (OPEX) expenditure and rapid advancement in technology encouraged all operators to go for sharing business models. In Pakistan, all four mobile operators Jazz, Telenor, Zong, and Ufone are actively adopting this model to maintain EBITDA (earnings before interest, taxes, depreciation, and amortization). Mainly there are two types of network sharing, Passive infrastructure sharing, and active resource sharing. Passive network sharing is widely used in Pakistan among operators.
International Journal of Advanced Computer Science and Applications, 2018
The massive multiple-input-multiple-output (MIMO) is a key enabling technology for the 5G cellula... more The massive multiple-input-multiple-output (MIMO) is a key enabling technology for the 5G cellular communication systems. In massive MIMO (M-MIMO) systems few hundred numbers of antennas are deployed at each base station (BS) to serve a relatively small number of single-antenna terminals with multiuser, providing higher data rate and lower latency. In this paper, an M-MIMO communication system with a large number of BS antennas with zero-forcing beamforming is proposed for the improved spectral efficiency performance of the system. The zero forcing beamforming technique is used to overcome the interference that limits the spectral efficiency of M-MIMO communication systems. The simulation results authenticate the improvement in the spectral efficiency of M-MIMO system. The spectral efficiency value using zero-forcing beamforming is near to the spectral efficiency value with the nointerference scenario.
IET Communications, 2017
In massive multiple-input multiple-output (M-MIMO) systems, the base station (BS) estimates the d... more In massive multiple-input multiple-output (M-MIMO) systems, the base station (BS) estimates the downlink and uplink channels using the uplink pilot training in conjunction with channel reciprocity property of time division duplex (TDD) operation. However, this channel estimation is contaminated due to the use of non-orthogonal pilot sequences for the uplink training in neighbouring cells that results in inter-cell interference. This study proposes an effective pilot contamination elimination scheme along with zero forcing precoding for multi-cell TDD M-MIMO systems. In the proposed scheme, each BS is assigned with a specific orthogonal variable spreading factor (OVSF) code row and a set of Zadoff-Chu (ZC) sequences are used for uplink pilot training. Then, the set of ZC sequences is multiplied element-wise at each BS with its OVSF code row to generate the orthogonality among the pilot sequences across the neighbouring cells. The proposed method can promise uncontaminated channel estimation and interference free downlink transmission without requiring the knowledge of the channels' second-order statistics and without increasing the training overhead by a factor equal to the number of interfering cells. The simulation results authenticate the effectiveness and superiority of the proposed scheme over other schemes.
International Journal of Advanced Computer Science and Applications, 2018
This proposed antenna model and progressing the investigation of an inset fed wideband circular s... more This proposed antenna model and progressing the investigation of an inset fed wideband circular slotted patch antenna is suitable for 5.2 GHz satellite C-band applications. A circularly shaped slot has been chosen to be etched on diminutive square patch (4.4cm*5.64cm) of the inset feed antenna. The object of this work is to develop an efficient and inexpensive transducer system to facilitate its compatibility with monolithic microwave integrated circuits; expenses are minimized for its fabrication and trail low profile for C-band satellite links. This paper focuses on the circular profile of the microstrip patch antenna intended for the proficient gain to enhance the performance of the satellite communication. The return loss of-21.79dB with the directivity 8.22dB and gain of 8.17dB have been estimated. The efficiency of 97% with VSWR of 1.22 compensates each other with better simulation results.
International Journal of Advanced Computer Science and Applications, 2018
Computed tomography angiography (CTA) has turned non-invasive diagnosis of cardiovascular anomali... more Computed tomography angiography (CTA) has turned non-invasive diagnosis of cardiovascular anomalies into a reality as state-of-the-art imaging equipment is capable of recording sub-millimeter details. Based on high intensity, the calcified plaques are easily identified in cardiac CTA; however, low density based non-calcified plaque detection has been a challenging problem in recent years. We propose an efficient method in this work for automated detection of the non-calcified plaques using discrete radial profiles. The plaque detection is accomplished using support vector machine to differentiate abnormal coronary segments. We investigated a total of 32 CTA volumes and the detection mean accuracy of 84.6% was achieved, which is in-line with the reported literature.
The <strong>Urdu-Sindhi Speech Emotion Corpus</strong> is a dataset collected at Mehr... more The <strong>Urdu-Sindhi Speech Emotion Corpus</strong> is a dataset collected at Mehran University of Engineering & Technology, Pakistan by a research team led by Dr. Zafi Sherhan Syed and Dr. Sajjad Ali Memon. The dataset consists on 1,435 audio recordings in total for seven types of emotions which include anger, disgust, happiness, neutral, sarcasm, sadness, and surprise in two low-resource languages of South Asia, that is Urdu and Sindhi. Due to ethical restrictions we cannot release audio recordings at the moment and instead release five feature sets from the OpenSmile toolkit. Please note that we will endeavour to compute any features for you locally and send those features back to you. If this interests you, please contact Dr. Zafi Syed at zafisherhan.shah@faculty.muet.edu.pk
Proceedings of the 2nd International Conference on Communication and Information Processing - ICCIP '16, 2016
In this paper, the performance of massive multiple-input-multiple-output (M-MIMO) with an infinit... more In this paper, the performance of massive multiple-input-multiple-output (M-MIMO) with an infinite number of the base station (BS) antennas is studied. The performance of such systems is only limited by the pilot contamination, which is a negative effect of reusing uplink pilot sequences in the neighboring cells. The channel estimates obtained in the presence of pilot contamination is contaminated, which results in inter-cell interference in the downlink data transmission. This paper shows the severity of pilot contamination in the multi-cell scenario and proposes the implementation of distinct orthogonal variable spreading factor code at each BS to mitigate the pilot contamination in the time-division duplex (TDD) multi-cell M-MIMO systems. The performance of the uplink and downlink sum rates of the proposed scheme is compared with those of the time-shifted pilot scheme for an infinite number of BS antennas. The simulation results show that the proposed scheme outperformed time-shifted pilot scheme, which shows the effectiveness and validity of the proposed scheme.
2019 2nd International Conference on Computing, Mathematics and Engineering Technologies (iCoMET), 2019
various advantages such as: easy to configure, low weight and low cost make microstrip patch ante... more various advantages such as: easy to configure, low weight and low cost make microstrip patch antenna (MPA) the first choice for wireless communication system. The structure of the patch antenna consists of dielectric material in between radiating patch and ground plan. In this paper we present the comparative performance analysis of 4 different shaped antennas. The shapes taken into consider are E, T, H and F. The antenna is designed to operate at is 2.4 GHz. The results of different antenna parameters such as return loss VSWR, radiation pattern, gain and directivity are analyzed on different frequency bands. The E-shaped patch antenna is found much better than the others with overall gain of 7.2 dB at 2.4 GHz. Which is suitable for RFID reader application. Simulation is done using High Frequency Structure Simulator (HFSS) antenna simulation tool.
International Journal of Advanced Computer Science and Applications, 2020
Parkinson's disease is a serious neurological impairment which adversely affects the quality of l... more Parkinson's disease is a serious neurological impairment which adversely affects the quality of life in individuals. While there currently does not exist any cure for this disease, it is well known that early diagnosis can be used to improve the quality of life of affected individuals through various types of therapy. Speech based screening of Parkinson's disease is an active area of research intending to offer a non-invasive and passive tool for clinicians to monitor changes in voice that arise due to Parkinson's disease. Whereas traditional methods for speech based identification rely on domain-knowledge based hand-crafted features, in this paper, we investigate the efficacy of and propose the deep acoustic embeddings for identification of Parkinsonian speech. To this end, we conduct several experiments to benchmark deep acoustic embeddings against handcrafted features for differentiating between speech from individuals with Parkinson's disease and those who are healthy. We report that deep acoustic embeddings consistently perform better than domain-knowledge features. We also report on the usefulness of decision-level fusion for improving the classification performance of a model trained on these embeddings.
Mehran University Research Journal of Engineering and Technology, 2017
Multicarrier transmission technique has become a prominent transmission technique in high-speed w... more Multicarrier transmission technique has become a prominent transmission technique in high-speed wireless communication systems. It is due to its frequency diversity,small inter-symbol interference in the multipath fading channel, simple equalizer structure, and high bandwidth efficiency. Nevertheless, in thetime domain, multicarrier transmission signal has high PAPR (Peak-to-Average Power Ratio) thatinterprets to low power amplifier efficiencies. To decrease the PAPR, a CCSLM (Convolutional Code Selective Mapping) scheme for multicarrier transmission with a high number of subcarriers is proposed in this paper. Proposed scheme is based on SLM method and employs interleaver and convolutional coding. Related works on the PAPR reduction have considered either 128 or 256 number of subcarriers. However, PAPR of multicarrier transmission signal will increase as a number of subcarriers increases. The proposed method achieves significant PAPR reduction for ahigher number of subcarriers as well as better power amplifier efficiency. Simulation outcomes validate the usefulness of projected scheme.
January 2019, 2019
Accurate segmentation of anatomical organs in medical images is a complex task due to wide inter-... more Accurate segmentation of anatomical organs in medical images is a complex task due to wide inter-patient variability and several acquisition dependent artefacts. Moreover, image noise, low contrast and intensity inhomogeneity in medical data further amplifies the challenge. In this work, we propose an effective yet simple algorithm based on composite energy metric for precise detection of object boundaries. A number of methods have been proposed in literature for image segmentation; however, these methods employ individual characteristics of image including gradient, regional intensity or texture map. Segmentation based on individual featres often fail for complex images, especially for medical imagery. Accordingly, we propose that the segmentation quality can be improved by integrating local and global image features in the curve evolution. This work employs the classic snake model aka active contour model; however, the curve evolution force has been updated. In contast to the conv...
International Journal of Advanced Computer Science and Applications, 2018
Wireless body area networks are being widely used due to the increase in the use of wireless netw... more Wireless body area networks are being widely used due to the increase in the use of wireless networks and various electrical devices. A Wearable Patch antenna is used for enhancement of various applications for WBAN. In this paper, a low profile wearable microstrip patch antenna is designed and suggested for constant observation of human vital signs such as blood pressure, pulse rate and body temperature using wireless body area network (WBAN) technology. The operating frequency of the antenna is taken as 2.45 GHz which lies in industrial, scientific and medical (ISM) frequency band. Polyester textile fabric with a relative permittivity of 1.44 and thickness of 2.85 mm is used as a substrate material. The proposed antenna is designed to achieve better return loss, VSWR, gain and low value of specific absorption rate (SAR) as compare to other existing wearable antenna. The achieved antenna return loss at 2.45 GHz is about-10.52 dB and gain of 7.81 dB. The VSWR value achieved at 2.45 GHz is 1.84, which is good in terms of good impedance matching. Other antenna field parameters like 2D and 3D gain, radiation pattern, and SAR value have been calculated. High-Frequency Structure Simulator (HFSS) is used to design and simulate the proposed antenna.
International Journal of Advanced Computer Science and Applications, 2018
International Journal of Advanced Computer Science and Applications, 2018
The performance of co-time co-frequency full duplex (CCDF) communication systems is limited by th... more The performance of co-time co-frequency full duplex (CCDF) communication systems is limited by the selfinterference (SI), which is the result of using the same frequency for transmission and reception. However, current communication systems use separate frequencies for transmission and reception, respectively. Therefore, SI is an important issue to be fixed for future-generation systems. As the radio frequency (RF) spectrum is very scared and a CCDF system has the potential to reduce the current spectrum use by half. In this paper, a CCDF communication system is modeled and a combination of RF and digital cancellations is used to mitigate the SI. The simulation results reveal that the proposed combination of RF and digital cancellation achieve the bit-errorrate of 10-11 at an interference-to-signal ratio of 10 dB, which is satisfying value for CCDF communication. The achieved efficiency of the proposed system is 13 bits/sec/Hz at a signal-tonoise ratio of 50 dB. The antenna separation of 35 dB is considered for the proposed model to keep the data loss as minimum as possible. The performance can be improved further by increasing digital-to-analog converter bits but with added complexity.
International Journal of Information and Electronics Engineering, 2015
The multi-carrier transmission signal in MC-CDMA has a high Peak-to-Mean Envelope Power Ratio (PM... more The multi-carrier transmission signal in MC-CDMA has a high Peak-to-Mean Envelope Power Ratio (PMEPR) which results in nonlinear distortion and system performance degradation. To reduce PMEPR, a pre-interleaver and error control coding based selective mapping method is proposed in this paper. This method generates 2 n sequences of the original data sequence via adding n PMEPR control bits to the original data followed by an interleaver and error control code to make original data more random. The covolutional codes, cyclic codes and low density parity check (LDPC) codes are used as error control codes. The proposed method achieves significant PMEPR reduction and avoids the need of side information transmission. The simulation results reveal the validity of proposed method. Index Terms-MC-CDMA, peak to average power ratio (PAPR), high power amplifier (HPA), selective mapping.
European Transactions on Telecommunications, 2006
In this study, we propose to apply interleavers as a mapping function of selected mapping (SLM) t... more In this study, we propose to apply interleavers as a mapping function of selected mapping (SLM) to reduce peak-to-average power ratio (PAPR) of multi-carrier code division multiple access (MC-CDMA) signals. Additionally, a new method is proposed to send information about selected interleaver without explicit side information. The proposed method employs a scramble code and pilot symbols sent through pilot channel. The SLM with pseudo-random interleavers enables MC-CDMA signal transmitter to obtain the same PAPR reduction ability as SLM with random phase rotation, that is conventional SLM with the best phase rotation way. We confirm that the receivers can detect selected interleavers without degradation of bit error rate by the proposed interleaver estimation method. Copyright # 2006 AEIT.
Journal of Communications, 2017
Massive MIMO has been acknowledged as a promising technology to counter the demand for higher dat... more Massive MIMO has been acknowledged as a promising technology to counter the demand for higher data capacity for wireless networks in 2020 and beyond. However, each Base Station (BS) requires good enough knowledge of Channel State Information (CSI) on both the uplink and the downlink as massive MIMO relies on spatial multiplexing. In Time Division Duplex (TDD) massive MIMO systems, this CSI is acquired using channel reciprocity. However, the use of nonorthogonal uplink pilot sequence due to limited coherence time leads to pilot contamination in TDD massive MIMO systems that results in inter-cell interference in the downlink data transmission. This paper proposes a design of orthogonal uplink pilot sequences for multi-cell TDD massive MIMO systems. We propose to use Zadoff-Chu Pilot Sequences (ZCPS) and eliminate pilot contamination during channel estimation process. In the proposed design, each BS is assigned with a specific orthogonal code and the set of ZCPS is multiplied element-wise at each BS with BS-specific orthogonal code to generate orthogonality among pilot sequences across neighboring cells. The proposed design eliminates pilot contamination during channel estimation process thus achieves significant sum-rate gains as verified by the simulation results.
International Journal of Wireless and Microwave Technologies
One of the key issues of wireless communication networks is the spectrum crisis, and studies note... more One of the key issues of wireless communication networks is the spectrum crisis, and studies noted that static licensed bands are in the under-utilization stage. Recently Cognitive Radio Network facilitates a solution to minimize the spectrum crisis in which unlicensed users can utilize the licensed spectrum without transmission interference. To achieve this task we used Machine Learning techniques for analyzing spectrum occupancy which is an efficient method to analyze spectrum occupancy and provides high accuracy. Supervised machine learning algorithms namely Logistic regression, K nearest neighbor, and Naive Bayes are used to classify a given frequency band. In this paper we collect spectrum samples of GSM 900, 1800, and 2100 bands using Rohde & Schwarz FSH6 Handheld Spectrum Analyzer for developing a dataset, using that dataset we trained the classifiers and analyze their classification performance accuracy. Results have shown the best performance on the validation and testing partition for various Unweighted Average Recall (UAR) of each classifier. Here the Logistic Regression classifier learns the best representation from their feature vector. This research is helpful to measure the spectrum occupancy of different static allocated licensed bands for 24/7. This will give better ideas about spectrum utilization, future spectrum allocation and comfort to serve more users in the limited spectrum. The occupancy measurements of current allocated spectrums can not only provide a convincing basis for making future spectrum allocation policies, but also provide technical support for the development of new communication technologies.
To document the sustained virological response (SVR) in rapid virological responders (RVR) of gen... more To document the sustained virological response (SVR) in rapid virological responders (RVR) of genotype-3 chronic hepatitis C with standard interferon (SdIF).
Objective: To determine the frequency of acute HCV infection after needle stick injury and its tr... more Objective: To determine the frequency of acute HCV infection after needle stick injury and its treatment outcome. Methodology: Patients with HCV positive needle stick injury and reporting within 72 hours of incident were selected. Co-infections with HBV, HDV, HIV, hematological disorders and depression were excluded. Anti-HCV was done at presentation and those testing positive were excluded. HCV RNA was done after two weeks or anti-HCV after six weeks of incident. Those testing positive were kept under observation for 16 weeks for spontaneous resolution. After this period HCV RNA and Genotype were done and therapy with Peg-interferon was started. Rapid, early and sustained virological responses were checked. Results: Two hundred eight patients with HCV positive needle stick injury were selected, 10 (4.8%) developed acute HCV infection out of them one (10%) had spontaneous recovery during the observation period of 16 weeks. seven (77.8%) achieved rapid virological response and eight (88.9%) achieved sustained virological response. Conclusions: Acute HCV is an uncommon disease to diagnose; it has favorable response to therapy if initiated early after a strict surveillance of patients for 8-16 weeks.