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Portable interfaced robot arms equipped with mobile user interactions are significantly being utilized in modern world. The application of teaching robotics is being used in challenging pandemic situation but it is still challenging due to mathematical formulation. This article utilizes the augmented reality (AR) concept for remote control-based human-robot interaction using the Bluetooth correspondence. The proposed framework incorporates different modules like a robot arm control, a regulator module and a distant portable smartphone application for envisioning the robot arm points for its real-time relevance. This novel approach fuses AR innovation into portable application which permit the continuous virtual coordination with actual physical platform. The simulation yields effective outcomes with 96.94% accuracy for testing stage while maintaining error and loss values of 0.194 and 0.183 respectively. The proposed interface gives consistent results for teaching application in real time changing environment by outperforming existing methods with an accuracy improvement of 13.4

A decade back, emergency voice communication was the only target to support the patient in an ambulance. It is now evolved from emergency voice communication to vital signal monitoring and operating the machines from the remote place. This evolution requires support from technology to meet the high data rates along with reliability for the specified applications. The millimeter-wave (mmWave) communication support high data rate requirements of vehicular communication. However, in the case of mmWave, the radio signals vary fast. It poses the implementation challenge to the mmWave system in this scenario. The other implementations challenges of mmWave are high path loss, severe blockage and frequent beam updates which inhibit seamless connectivity (reliability) to vehicular nodes. However, the reliability is always a prime concern for any vehicular communication system. This paper addresses these challenges by implementing a novel energy-efficient strategy based on RSUs deployment and radio access technology (RAT). The strategy is to deploy RSUs on either side of the road and use an optimal combination of mmWave and microwave RAT. The essential analysis of such a hybrid system involves the evaluation of parameters based on the analytic model. Hence, this paper analytically obtains the expression for seamless coverage and connectivity. The analysis is also extended to rate and energy efficiency calculations. The analysis is supported by probabilistic models-based simulations that agree closely with computation results. The results claim that the proposed model leads to improved performance in terms of coverage and rate while maintaining the cost and energy efficiency within the limits.

Neuronal population activity in the brain is the combined response of information in the spatial domain and dynamics in the temporal domain. Modeling such Spatio-temporal mechanisms is a complex process because of the complexity of the brain and the limitations of the hardware. In this paper, we demonstrate how information processing principles adapted from the brain can be used to create a brain-inspired artificial intelligence (AI) model and represent Spatio-temporal patterns. The same is demonstrated by designing the tiny brain using spiking neural networks, where activated neuronal populations represent information in the spatial domain and transmitting signals represent dynamics in the temporal domain. Spatially located sensory neurons excited by input visual stimuli further activate motor neurons to trigger a motor response that causes behavior modification of the robotic agent. Initially, an isolated brain network is simulated to understand the excitation part from sensory to motor neurons while plotting waveform between membrane potential and time. The response of the network to stimulate robot body movements is also plotted to demonstrate representation. The simulation shows how the response of particular visual stimuli modifies behavior and helps us understand the body and brain synchronization. The perceived environment and resultant behavior response allow us to study body interaction with the environment.

This work proposes a novel frequency-reconfigurable circular patch antenna incorporated with a rectangular slot and a narrow slot capable of producing constant dipole-like radiation patterns. The antenna compactness is achieved with the integration of the rectangular slot defected ground structure (DGS) on the ground. The proposed antenna is able to perform continuous frequency tuning between 1.91 and 2.77 GHz with a frequency ratio of 1.5:1, in addition to stable dipole-like radiation patterns. The resonant frequency of the antenna is controlled by tuning a simple DC biasing network that consists of three RF varactor diodes located on the narrow slot DGS. Implementing the DC biasing network at the narrow slot DGS while maintaining the large slot DGS helps the antenna miniaturization and maintains the constant dipole-like radiation pattern over all frequency tuning range. The results are validated via simulations and experimental validations in terms of reflection coefficients and the radiation patterns. Measurements indicated that an impedance bandwidth of 85 MHz is featured for each tuned frequency band, with dipole-like patterns and an average gain of 1.57 dBi.

Electroporation has an application in the selective delivery of drugs explicitly into cells. However, the challenge is to achieve efficiency in delivering the drugs. The key parameter responsible for successful electroporation-mediated drug delivery is induced transmembrane voltage (ITMV). The Food And Drug Administration (FDA) has recently approved the clinical trials of DNA plasmid delivery of the COVID-19 vaccine through electroporation. The requirement is to develop a COVID-19 vaccine within a limited time. Hence, the extensive amount of laboratory experiments are not feasible. It has increased dependency on simulation-based analysis. The simulations of electroporation depend on ITMV expression for the specified cell and the environment. In this paper, we have derived the closed-form expression of ITMV (∆Vm). The closed-form expression is used in COMSOL Multiphysics simulation to obtain extracellular concentration variation as a function of time. The simulation results match the empirical results from the literature and hence validate the closed-form expression. The closed-form expression will reduce the development time of electroporation-assisted COVID-19 vaccine delivery. © 2021 by the authors.

The fast-moving world relies on intelligent connected networks to support the numerous applications of the expanded Internet-of-Things (IoT). The evolving communication requirements of this connected world require a new sixth generation (6G) radio to enable intelligent interaction with the massive number of connected objects. The energy management of billions of connected devices supporting massive Internet-of-Things (IoT) applications is the main challenge. These IoT devices and connected nodes are energy limited, and hence, energy-aware solutions are needed to enable seamless information flow between these communicating nodes. This paper presents an intelligent network solution for improved energy efficiency in a 6G-enabled expanded IoT network. A cell-free massive multiple input multiple output (mMIMO) technology is utilized for maximum energy efficiency with optimum network resource allocation. A practical power consumption model is proposed for the designed network topology which contains all the power components related to data transmission and circuit power. The proposed scheme aims to achieve maximum energy efficiency by the optimal allocation of pilot reuse factor and access point (AP) density for a given number of antennas at each AP and number of users. It is observed that the maximum energy efficiency of 5.2362 Mbit/Joule is achieved at the AP density of 29 and pilot reuse factor of 4 with PMMSE receive combining. In the end, the role of energy efficiency and area throughput tradeoff on the system performance is also evaluated, which suggests that both the energy efficiency and area throughput can be jointly increased until maximum energy efficiency is reached at a point.

Internet-of-Things (IoT) networks are witnessing a rapid proliferation of connected devices and mobile terminals each day. The wireless information flow between these massive battery-powered devices has a huge energy burden and will lead to an energy crisis in the near future; thus, there is an urgent search for sustainable energy networks. To offer a sustainable energy solution in order to meet the energy demands of these massive IoT networks, this paper presents a dynamic practical model that enables the efficient management of power resources. Two user-scheduling algorithms, namely, minimum distance scheduling (MDS) and maximum channel gain scheduling (MCS), are proposed; when these algorithms were used alongside a power optimization, they led to improved network efficiency. Further, the network’s performance was measured with parametric variations in the number of access points (APs); the deployment of APs and AP configuration is carried out for different precoding schemes. The impact of spatial correlation and the access to perfect channel state information (CSI) on the spectral efficiency of the system was also evaluated. In the end, the study compares the performance of different power-allocation methods and suggests that the power allocated to a particular user node by an AP can be controlled using the proposed algorithms. It is observed that, as compared to the MDS algorithm, the MCS algorithm results in better spectral efficiency for all the users with fractional power allocation. In addition, each AP assigns a maximum power of 141.7 mW to a user with strong channel conditions with the AP, and a minimum power of 3.1882 mW to the user with the worst channel conditions using centralized PMMSE precoding.

A phenomenon that transiently increases the permeability of the cells is known as electroporation. It is the basis for number of the applications in biomedical domains. It is essential to consider requirement of high precision and the overall size of electroporator. The recent decades have seen the development of solid-state power electronic modules. The modules enable generation of high voltage millisecond and nano-second pulses with options to reduce the overall size of the equipment. The selective modules are verified with experimental models and available for commercial usage. While the other modules are still undergoing optimization processes. The generator generates pulses for varying performances. Hence, this paper presents knowledge for different nanosecond and millisecond pulse generating circuits for electroporation purposes. The performance parameters like the width of the pulse, its amplitude are compared for different circuit topologies. The performance analysis of different topologies and their impact on the performance of the electroporation at the cell biology level are considered in this paper.

The step graded antenna is designed for the measurement of electrical property inside the concrete samples. This paper designs, simulates and fabricates the single band microstrip antenna at the frequency of 2.76 GHz. The simulated results are compared and analysed with measured results for the designed antenna. It has been noted that the measured and simulated values corresponding to reflection coeffcieints results in offset of 0.02 GHz. The designed antenna is tested on two different composition of concrete samples. The disparity in the reflectivity of both the samples is observed due to the variance in the composition of the concrete structure. The operating frequency of the proposed antenna changes from 2.76 to 2.72 GHz when applied to both concrete samples. Thus the designed antenna can be used for the soil moisture content measurement for structural health monitoring.

This paper considers a cooperative wireless system with multiple antennas at the source. A multi-antenna relay equipped with a power splitter is introduced between the source and destination. It ut...

Background: The paper considers the wireless system with large number of users (more than 50 users) and each user is assigned large number of antennas (around 200) at the Base Station (BS). Objective: The challenges associated with the defined system are increased power consumption and high complexity of associated circuitry. The antenna selection is introduced to combat these problems while the usage of linear precoding reduces computational complexity. The literature suggests number of antenna selection techniques based on statistical properties of signal. However, each antenna selection technique suits well to specific number of users. Methods: In this paper, the random antenna selection is compared with norm-based antenna selection. It is analysed that the random antenna selection leads to inefficient spectral efficiency if the number of users are more than 50 in Multi-User Multiple-Input Multiple Output (MU-MIMO) system. Results: The paper proposes the optimization of Energy-Efficiency (EE) with random transmit antenna selection for large number of users in MU-MIMO systems. Conclusion: Also the computation leads to optimization of number of transmit antennas at the BS for energy efficiency. The proposed algorithm results in improvement of the energy efficiency by 27% for more than 50 users.

Purpose The major challenges in the modern-day wireless communication systems are increased co-channel interference owing to large number of users and the increased energy consumption owing to high circuit and/or hardware power consumption. Hence, the purpose of this paper is to present a practical approach involving linear precoding, channel estimation, user selection (US) and transmit antenna selection (AS) for enhanced reliability in multiuser multiple-input multiple output (MU-MIMO) system. Design/methodology/approach The proposed technique considers systematic and optimum deployment of users and transmits antennas for each selected user which enhances the sum rate or the system capacity. The comparison of algorithms, namely, norm-based and capacity-based US is presented with its implementation with precoding techniques, namely, block-diagonalization (BD) and zero-forcing with combining (ZFC) which is used to minimize co-channel interference. In this paper, a power consumption model is proposed for energy efficiency calculation in MU-MIMO system. Also, post analysis, the variant of US and AS algorithms optimizing the performance of BD and ZFC precoding technique is proposed. Findings It is seen that the proposed MU-MIMO system with norm-based US and norm-based AS improves over existing US-based systems by 43% in terms of sum rate and 19% in terms of energy efficiency for 100 users. Originality/value It is seen that the proposed MU-MIMO system with norm-based US and norm-based AS improves over existing US-based systems by 43% in terms of sum rate and 19% in terms of energy efficiency for 100 users.

The cultural heritage has its importance due to the information communicated by the heritage to the future generations. It is difficult to preserve cultural heritage over the centuries because of their volatile nature. In this paper, the preservation aids are considered for sculptures. The sculpture also includes the type of monument. The challenges are face deterioration during logistic and handling. Hence, it destroys the information carried by sculpture. In addition, the knowledge about materials used for construction of these sculptures help in maintenance of these sculpture. It helps in reconstructing the shape and color, which have been damaged earlier. The common techniques reported in the literature for broken structure and material estimation are optical coherence tomography (OCT), X-ray, THz scanning and Raman spectroscopy. These techniques used for retrieving material information are not portable and are costlier. Thus, the need is established in this paper for the device offering 3D scanning along with the material details of each scanned pixel. This paper aims at material estimation of old age sculptures from 11th century CE and 13th century CE housed at Government Museum and Art Gallery, Chandigarh, India using radio frequency technique. The device captures the 3D scanning of the sculptures to maintain its heritage for a longer time. Further, the device needs to be portable and affordable so that it can be provided to various stakeholders of culture heritage preserve.

Apple is one of the most popular fruits due to its dietary composition and the presence of biologically active compounds that have positive impacts on human health. This is the reason it is cultivated extensively worldwide. To preserve food items drying is one of the oldest techniques. The dried apples can be stored for a longer duration and are used as packaged snacks. Fruits can be dried rapidly with the help of microwave drying technique and hence it is used by industries to dry food items at a commercial scale. In this research paper, the microwave drying technique is applied to an apple in a COMSOL Multiphysics simulator. Then the results are observed to know at what temperature and for how much time apple should be dried so that its nutrients remain preserved.

The major challenges faced by the mobile users are the poor quality of communication and the fast battery drainage. The varying channel characteristics in wireless communication is the main reason for huge signal drops and poor signal quality. The channel estimation plays an important role and is crucial for determining the accuracy of the system. In this paper, the two channel estimation techniques, namely least square (LS) and minimum mean square error (MMSE) are analyzed for multi-antenna communication scenario. The different practical channel scenarios are considered to evaluate the performance of the proposed system in terms of average sum spectral efficiency (SE). It is observed that the maximum average sum SE is obtained with MMSE channel estimation for Rician fading channels. The impact of varying channel statistics with spatial correlation is also evaluated for different pilot reuse factors. Further, the comparison of different receive combiners based on the channel estimates for signal detection is performed in terms of computational complexity.

Quantum-dot cellular automata (QCA) is one of the applicable alternatives to current CMOS because of static hazards, leakage current and smaller area requirement. Therefore, it has achieved an important place in a digital circuit. In this work, the design of an efficient 2:1 demultiplexer structure based on a 3-input majority gate is proposed. This DEMUX design outperforms the existing 2:1 DEMUX designs available in the literature in terms of effective area, cell count and delay. The proposed demultiplexer design has 0.25% less effective area, 21 number of QCA cells with the delay of 1 clock cycle.

In this paper a compact wideband Filtenna structure with stopband characteristics has been presented. The proposed filtenna is a planar elliptical patch with a CSRR structure embedded in the partial ground. The elliptical shape is utilized to attain the wideband characteristics whereas the CSRR is etched out to filter out the undesired bands. This filtenna design exhibits an impedance bandwidth of 3.3 GHz ranging from 2.47 GHz to 5.77 GHz covering the WLAN (2.4/5.2 GHz) and WiMAX (2.5/ 3.5/ 5.5 GHz) bands and effectively rejects the higher bands beyond 5.77 GHz. The designed filtenna achieves a maximum gain of 4.11 dBi and a bidirectional radiation pattern over the desired bandwidth. The overall dimensions of the proposed filtenna is 40 mm x 50 mm x 1.6 mm with the patch area 14 mm x 10 mm. The proposed filtenna is designed, simulated and optimized using CST Microwave Studio and has been fabricated and tested to validate the proposed design.

The health benefits of Indian gooseberry have resulted in a tremendous growth in its consumption in the form of tasty candy and marmalade prepared by drying process. The candy production process is...

The major challenge in the current scenario of wireless system is increasing number of users and hence increased co-channel interference within the limited spectrum available for communication. The compromise in terms of user quality and reliability of communication system is evitable from increased number of call drops and busy channels during mobile voice calls. The above mentioned challenge is attributed for increase in the number of users accommodated in the defined spectrum. The paper presents a novel user selection and transmit antenna selection based approach for enhanced reliability in multi-user multiple input multiple output system, which is next generation wireless system. In contrast to existing technique for multiple antennas and which is evolution of regular channel inversion with block diagonalization, the proposed technique considers systematic and optimum deployment of user selection in the system to enhance sum rate or the system capacity. The comparison of algorithms viz. random, norm based and capacity based user selection is presented with its implementation with precoding techniques which is used to minimize co-channel interference. The analysis proposes that, for each selected user if the transmit antennas are chosen with presented algorithm, the sum rate is improved by 17%. Also, the bit error rate performance of linear precoding with user selection is equivalent to non-linear precoding without user selection.

Wireless technologies are growing at a rapid speed in all around the world. In wireless technologies domain 5G is the next big thing to research. This topic elaborates about internet of things in 5G system which is definitely a game changer in upcoming generations. It’ll enhance the wireless services in upcoming times and will open the sea of opportunities as well as services. Recent 4G LTE technology is insufficient in matching up the data transfer speed, AI, self-driven vehicles, health systems, space technology and multiple instruments connectivity for next times. For these concerns 5G is going to be the pristine technology to meet our demands in future. Health systems and space technologies are changing at a superfast speed and these are currently on 4G technology. All the futuristic applications will require high band width, faster connectivity at multiple devices and latency with data rates. We’ll have an elaborative detailing about the obstacles and possibilities in 5G IOT systems.

An electrically tunable, textile-based metamaterial (MTM) is presented in this work. The proposed MTM unit cell consists of a decagonal-shaped split-ring resonator and a slotted ground plane integrated with RF varactor diodes. The characteristics of the proposed MTM were first studied independently using a single unit cell, prior to different array combinations consisting of 1 × 2, 2 × 1, and 2 × 2 unit cells. Experimental validation was conducted for the fabricated 2 × 2 unit cell array format. The proposed tunable MTM array exhibits tunable left-handed characteristics for both simulation and measurement from 2.71 to 5.51 GHz and provides a tunable transmission coefficient of the MTM. Besides the left-handed properties within the frequency of interest (from 1 to 15 GHz), the proposed MTM also exhibits negative permittivity and permeability from 8.54 to 10.82 GHz and from 10.6 to 13.78 GHz, respectively. The proposed tunable MTM could operate in a dynamic mode using a feedback system for different microwave wearable applications.

The crop-waste is available in abundant to generate energy. The energy conversion process involve production of biofuel from crop-waste. This paper considers the conversion of rice straw to energy. The conversion involve the preprocessing of rice straw which includes drying and its conversion to powder form. This paper proposes the microwave assisted drying process for rice straw. The single strand of rice straw is considered in the paper. The Multiphysics simulation is performed to understand the heat generation and heat-transfer rate with variation in the size of rice straw. The proposed process involves the cutting of rice straw to specific sizes. The rice straw size plays an important role in absorbing microwave energy. The heating pattern depends on the mode of transverse electric field interacting with specified size of rice straw. The different modes getting excited in the rice straw depends on its size. It is observed in this paper that the large size of rice straw help in achieving multiple modes in a single strand of rice straw. Hence, it results in optimized microwave process to achieve the uniform heating in rice straw. The cutting of rice straw before microwave processing requires the rice straw to size between 8 cm to 12 cm.

This paper proposes a reconfigurable antenna for RFID system which can operate between 860MHz to 960MHz frequency that belongs to ultra-high frequency (UHF) band used in Malaysia with the center frequency of 910MHz. One rectangular slot and two triangle-shaped slots are used in designing this antenna. A good circular polarization obtained from the slotted structure along the diagonal axis in the design. RF pin diodes are used as the switching mechanism of the antenna. However, in this work to proof the concept of switching mechanism, copper pins are used as artificial switches. Parasitic elements are deployed on the right and left side of the driven element to assist the radiation pattern reconfiguration. Overall, the proposed antenna able to steer the beam at approximately at -30°, -16°, and 10° with peak gain of 3.2dB and average gain of 2.5dB. With this result, overall coverage of UHF RFID reader antenna could be improved.

Mutation in islet amyloid polypeptide (IAPP) gene results into its protein misfolding and fibril formation. Isolation of various mammalian species shows its conservation from 89- to 93-amino acid sequence sharing homology with cats, rats, mice, and guinea pigs. For the present study, detailed phylogenetic analysis is carried out for the upstream promoter region of IAPP gene, IAPP messenger RNA (mRNA), and proIAPP protein of nine mammalian species. Sequence analysis has shown partial conservation among the rodent species and the canidae group; however, the primate group species has shown maximum conservation of all sequences under considerations with respect to the human IAPP sequences. Our novel approach of analyzing mRNA and protein sequence conservation of proIAPP delineates the importance for developing IAPP models in closely related species sharing a common ancestor with the time divergence. Further, transcription factor binding sites were critically analyzed for the upstream promoter region of the IAPP gene. These probable binding sites were predicted for DNA motifs recognized by transcription factors, which may prove to be helpful in predicting the regulatory mechanism in understanding the regulation of IAPP gene under in vitro or in vivo conditions. Therefore, confirming the co-evolutionary relationship of IAPP among different species will help us guide in studying transcription factor binding site for poorly studied IAPP gene and targeting disease mutation initiating pancreatic amyloidosis in clinical applications. The phylogenetic and gene promoter analysis presented in the paper reveals regulatory elements for beta cell death caused by pancreatic amyloidosis and resulting in type 2 diabetes (T2D) onset.

In cognitive radios, the primary user sensing plays an important role in defining a compromise between spectrum efficiency and licensed user interference. In this paper, the performance of cognitive radio is optimised using human opinion dynamics (HOD) inspired continuous opinion dynamics optimiser (CODO) with sensing parameters and throughput as arguments of objective function. The optimisation parameters are throughput, probability of false alarm and sensing time under varying signal to noise ratio (SNR) conditions with fixed frame period and at least 90 % probability of detection. Further, a new concept of human interaction for forming opinions is proposed to explore the idea of sensing-throughput optimisation. A statistical analysis showed that the proposed algorithm exhibits an improvement of 0.2 % in probability of detection with the condition that probability of detection is at least 90 %, as per the Federal Communication Commission (FCC) guidelines. Here, the frame period is kept fixed at 224.25 ms and the sensing time does not exceed 31.59 ms. There is also a drop of 5.25 % in false reports and an enhancement of 0.08 % in normalised throughput as compared to swarm intelligence technique when probability of detection is 95 % for the above frame period and sensing time. This implies that the cognitive user will not have to vacate the band on wrong reporting and can continue transmitting the data until the primary signal is indeed detected. Further, a maximum normalised throughput of 0.9088 is recorded at a minimum sensing time of 17.10 ms indicating that only ~8 % of the frame is utilised for sensing. Keywords

Circuit designing with quantum dot cellular automata is one of the most recent technologies which aim at scaling of devices. In this logic design technique, the organization of quantum cells defines the circuit. It is based on field coupled computing. The quantum dot cellular automata has numerous advantages including less area occupied, lack of interconnects, higher clock frequency, and since it doesn’t involve transfer of electrons or flow of current, it has the potential to perform low power calculation. This paper presents the comparison of 1-bit memory cell designed using CMOS technology and quantum dot cellular technology. The quantum dot cellular technology results in lesser occupied area at high clock frequency.

Radio devices employ the technology of cognition to sense the radio frequency environment. Cognitive radios are mainly for reliable communication and for efficient usage of spectrum resources. They identify an apt action that needs to be applied to a particular situation called reasoning. The results of applied actions provide information which helps them to modify their behavior called learning. Learning can be categorized as supervised learning and unsupervised learning. In supervised learning, the radio device already has some knowledge about the surrounding environment. In unsupervised learning, the radio device has no knowledge of the surrounding environment. To design the real cognitive systems, various AI techniques are metaheuristic algorithms, rule-based systems, artificial neural networks, ontology-based systems, hidden Markov models and case-based systems. This paper focusses on the learning aspect of the CR and the role of artificial intelligence in CR.

In this paper, an optimized ultra-compact planar inverted F antenna (PIFA) is proposed. Planar inverted F antenna (PIFA) is most commonly used antenna in modern day Mobile devices. While electronics industry is starving for compactness in their design, the concept used in the proposed design further reduces size of antenna. The overall dimensions of proposed antenna are 14.94 × 16 mm for 3G/4G standards. In proposed design 21.61% size reduction is reported in comparison to conventional rectangular patch PIFA designs. The concept can be further utilized in designing antenna for different standards by optimizing size for specific frequency. A fractal shape Patch shorted at one end is used in the proposed design. The fractal patch is extended 6.59 mm above the ground plane. The comparison is performed between measurement of fabricated and simulated S11 for proposed antenna. The novelty of design is inherited in extension of edges of patch towards ground which enable further reduction in size of antenna. Parametric optimization of antenna is performed for calculation of extended edge dimensions. Return loss for fabricated antenna is measured using vector network analyzer. The results of fabricated antenna show good agreement with simulated results and calculations.

In this paper, a new compact hybrid fractal antenna with ultrawideband (UWB) behavior is proposed. Two merged fractals shapes, i.e. Sierpinski carpet and Sierpinski Gasket fed with coplanar waveguide (CPW) feed make patch as multiband and broadband antenna. The antenna is optimized using particle swarm optimization for side length of Sierpenski Gasket fractal and bandwidth. The overall width of the patch is taken as a parameter for optimizing bandwidth. The total size of presented antenna is 59 × 29 mm2. The antenna resonates at 2–5.2 GHz, so that wideband operation is observed. Antenna with this type of characteristics can be used when UWB response at lower frequencies is required. Sierpenski Gasket performs two functions in the proposed design, i.e. to radiate as well as impedance transformer to Sierpenski carpet. The proposed design presents novelty in design to achieve proper impedance matching to edge of Sierpenski carpet design with CPW feed by making Sierpenski Gasket as impedance transformer.

The ever increasing demand of wireless communication systems has led to search of suitable spectrum bands for transmission of data. The research in the past has revealed that radio spectrum is under-utilized in most of the scenarios. This prompted the scientist to seek a solution to utilize the spectrum efficiently. Cognitive Radios provided an answer to the problem by sensing the idle (licensed) bands and allowing (secondary) users to transmit in these idle spaces. Spectrum sensing forms the main block of cognition cycle. This paper reviews the current trends in research in the domain of spectrum sensing. The author describes the type of channel being modelled, diversity combining schemes used, optimal algorithms applied at fusion centre, spectrum sensing techniques employed. Further, the research challenges are discussed. It is presented that various attributes like sensing time, throughput, rate reliability, optimum cooperative users, sensing frequency etc. needs to be addressed. A trade-off needs to be established to optimize two opposing parameters like sensing and throughput.

The scarcity of spectrum can be overcome by using the spectrum efficiently and effectively. There is a need for devising techniques that can help in sensing the spectrum judiciously so that the Secondary Users can optimally access the spectrum holes. This will support higher transmission of data, thereby enhancing the throughput. Further, the presence of Primary Users should be detected accurately in order to avoid interference. The sensing-throughput trade-off problem of spectrum sensing stage of cognitive radios can be optimized by means of computational intelligence techniques like swarm intelligence. This paper implements Particle Swarm Optimization technique to optimize Throughput, Probability of false alarm and sensing time under varying Signal-to-Noise Ratio conditions. It has been studied that bigger swarm-size does not improve the results, but takes longer processing time.

Cognitive Radio is a technology that enables unlicensed users (referred to as Secondary users) to use the spectrum of the licensed users (i.e. the Primary Users) whenever the licensed user is not transmitting data. This utilizes the spectrum efficiently. Cognitive Radio Networks (CRNs) detect Primary Users (PUs) using spectrum sensing and utilizes the spectrum holes (or vacant bands) for the transmission of data of Secondary User (SU). Spectrum sensing is carried out in a fixed time period called ‘Time Frame’. This Time Frame is divided into sensing time and transmission time. Higher sensing time will lead to better detection of PU but will lead to lesser transmission time and hence lesser throughput. On the contrary, if transmission time is higher, then sensing time is less, so PU detection will be compromised. It also leads to PU interference. There is a need of a tradeoff between sensing time and transmission time. Thus, there is a need for some optimal sensing time at which there is maximum possible throughput and no interference with the licensed user. This paper proposes a hybridized Ant Colony Optimization (ACO) - Particle Swarm Optimization (PSO) technique for spectrum sensing in cognitive radio networks. The results depict that the proposed technique is better than standalone optimization technique in terms of total error rate, throughput, probability of detection for varying sensing time and probability of false alarm.