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In this paper, three millimeter wave antennas are presented for 60 GHz. Each antenna is an array of 2 x 2 microstrip antennas. All three antennas utilize thin substrate of RT Duroid 5,880 having permittivity εr = 2.2. The basic design of 2 x 2 array antenna utilizing RT Duroid is extended for two superstrate loaded antennae designs. The first design uses foam and the other design uses RT Duroid with air gap as superstrates. 2 x 2 array patch engraved on RT Duroid above ground plane acts as driven patch, while the patch incised upon the superstrate acts as a parasitic patch. Optimization of the basic design achieves highest gain in millimeter wave region, whereas the superstrate loaded design results in a much wider bandwidth. A comparison of all design configurations is carried out through the sensitive study of the simulation results, including return loss, polarization and radiation patterns, which validates the designs for millimeter wave region. [ABSTRACT FROM AUTHOR]

Phased Array Antennas (PAA) are the ideal solution for a variety of system applications, including air traffic control and collision avoidance radar for WLAN and cellular communication. A microstrip antenna array is used as it is easy to design and fabricate. It has small size, lightweight and efficient and high gain. Antenna array designs are important areas of research in active phased array RADAR that can meet the subject requirement. Microstrip antennas are used in a variety of wireless applications including radars, cellular phones, wireless sensor networks and in medical applications. The paper reviews different configurations of microstrip antenna array for phased array radar. [ABSTRACT FROM AUTHOR]

Providing broadband internet for all people using prevailing technologies is a challenging task, especially for communities who live in rural and remote areas. One possible solution to provide broadband internet for rural areas is using wireless technologies which work at unused spectrum. TV White Space (TVWS) scenario in developing countries is much unlike those in developed countries. The availability of underutilized spectrum in UHF band is significant in these countries in contrast to developed countries, where only sporadic spectrum gaps are available. The paper describes issues related to TVWS usage for secondary application in a rural area of South-East, Nigeria. In order to provide broadband internet for rural and remote areas, feasibility of TVWS was done. The network architecture for the proposed system was modeled using the reality of available communication infrastructure. The propagation model was developed and the propagation prediction of the proposed network was done using a radio planning tool. [ABSTRACT FROM AUTHOR]

In medical fields, detection of brain tumors and their feature extraction is very important. By observing various image modalities, different anatomy structures of human brain can be visualized. It is very difficult to identify the abnormal tissue structures of brain using simple imaging techniques. Image processing technique used to detect brain tumors and classify them contains several steps. The steps include preprocessing, feature extraction and classification. To classify and recognize the images, feature extraction techniques are applied. The paper reviews suitable brain tumor texture feature extraction techniques and classification methods. These methods are very useful to classify the benign and malignant tumors of brain. These techniques are more beneficial to extract the hidden information of an image, and this feature set gives high classification accuracy. [ABSTRACT FROM AUTHOR]

The paper explorers Free Space Optical (FSO) communication with its flashes and corns. FSO technology is useful where the physical connection is impractical due to high cost or other considerations, and in most cases, optical data transmission is done via optical fibers, because it allows transmission over relatively large distances without alignment issues and relatively very less disturbing influences of atmosphere. But optical data transmission using fiber has also many limitations. Some limitations are removed by FSO technology, such as it provides high data rates, low power consumption, low installation cost and easily upgradable. FSO performance parameters, i.e., internal and external parameters, and some modulation techniques used in FSO technology are also discussed. [ABSTRACT FROM AUTHOR]

The paper investigates and compares the performance parameters like load, delay, throughput, and data sent and received for a wireless network. The study has been conducted using two network simulators, Network Simulator-2 (NS-2) and Opnet Modeler (IT Guru Academic Edition), which are widely used in the field of network simulations. The network that has been selected is the wireless network consisting of 12 nodes each with Ad-hoc Ondemand Distance Vector (AODV) as routing protocol, the application used is FTP (File Transfer Protocols) and the bandwidth selected is 11 Mbps for all kind of communications. [ABSTRACT FROM AUTHOR]

In recent years, reversible logic has gained importance in several emerging fields such as nanotechnology, quantum computing, optical computing and cryptography. The paper proposes a design for gray to binary code converter using reversible logic. The proposed design shows better performance in parameters such as gate count, constant inputs, quantum cost and garbage outputs, than the existing designs. [ABSTRACT FROM AUTHOR]

Femtocells are the new emerging technology of heterogeneous networks, which are used to improve the signal strength of the networks at homes or indoor . These femtocell devices are operated by Internet or broadband connection to provide good quality of signal strength at homes or indoor where it is difficult to get direct signals or good quality signals from the macro cells. The ranges of these femtocell devices are around a few meters, which are very small. Long-Term Evolution (LTE) is purely based on hard handover, which follows the standard handover technology. Due to the small range of femtocell devices, frequent numbers of handovers occur . So conventional handover schemes generate more delay during handovers, which is not suitable for femtocell networks. In this paper, we discuss the temporary area network handover technique and compare the temporary area-based technique with standard handover technique and prefetch-based techniques. [ABSTRACT FROM AUTHOR]

The present paper investigates the capacity and secondary data rate of Multiple Inputs and Multiple Outputs (MIMO) relay channel with Amplify and Forward (AF) techniques by using cognitive and cooperative communication. The capacity of the system can be maximized by using Optimum Power Allocation (OPA) algorithm in place of equal power allocation among all nodes, while assuming that all nodes have fully Channel State Information (CSI). It has been considered that MIMO cognitive relay with spectrum sharing and cooperative strategy between nodes would maximize the secondary data rate, lifetime and enormous use of the spectrum. Our aim is to maximize the lifetime, secondary data rate and efficient spectrum use. MIMO relay is going to amplify and forward relay techniques. It means that relay is not going to decode the signal received from the source. The results showed that MIMO capacity and secondary data rate with AF relay schemes increase without using extra power and spectrum. [ABSTRACT FROM AUTHOR]

This paper focuses on the design and implementation of pipeline monitoring system using acceleration-based wireless sensor network. In this paper, a Micro Electro Mechanical Systems (MEMS)-based wireless sensor network was developed for nondestructive monitoring of pipeline systems. The system incorporates MEMS accelerometers for measuring flow-induced vibration on the surface of a pipe to determine the change in water pressure caused by rupture and the damage location. Also, field measurements of vibration were performed in pipe sections of a water-filled loop subjected to a wide range of flow rates. In addition, experimental investigation of the relationship between flow-induced vibration and the pressure fluctuations was carried out. The experimental results showed that there is a sharp change in the induced vibration of the pipe surface of about 0.07 g force and 0.22 g force, when the valves were half opened and completely opened, respectively. The results also showed that the correlation coefficient of the measured data is 1.00, which showed that there is a positive linear relationship between the flow-induced vibrations and pressure fluctuations. The results also showed that a nonlinear but proportional relationship exists between the water flow rate and flow-induced vibrations. [ABSTRACT FROM AUTHOR]

Evolutionary optimization algorithms have recently been applied for the optimal design of digital FIR filters. These algorithms approximate the frequency response of the desired filter by optimizing the coefficients of the actual filter. In this paper, a recent method, namely, Teaching-Learning-Based Optimization (TLBO) and Differential Evolution (DE) algorithms are applied for the design of linear phase digital FIR filter. The results obtained for the case of TLBO algorithm are compared statistically with those obtained using DE algorithm. The results showed faster convergence in the case of TLBO method. However, the approximation to the desired frequency response is found to be better in the case of DE algorithm. The frequency responses obtained using these algorithms are compared with those obtained using Parks-McClellan method of FIR filter design, and it is found that better performance is exhibited by TLBO and DE algorithms. [ABSTRACT FROM AUTHOR]

The paper introduces an approach to solve a quadratic equation with resource constraints using MicroBlaze soft-core processor in Xilinx EDK including both hardware and software frameworks that are used in building and implementing the system. The paper also proposes a methodology to design and implement a customized IP core for MicroBlaze-based SoC. The uniqueness of this system lies in its implementation of the solution of the quadratic equation by passing data to an adder and a multiplier core that are interfaced to the MicroBlaze-based system that was implemented on Spartan 6 xc6slx45 FPGA. A VHDL code was written for the adder and multiplier core. An embedded C code was written to run the MicroBlaze SoC in the Xilinx SDK. A board from Digilent having Xilinx Spartan 6 xc6slx45 FPGA, Xilinx ISE 12.3, Xilinx EDK 12.3 and Xilinx SDK 12.3 was used to design and implement the system, and the output was demonstrated via UART on hyper-terminal of a computer. [ABSTRACT FROM AUTHOR]

The paper describes the performance analysis of different feeding mechanisms for Rectangular Dielectric Resonator Antenna (RDRA). Due to the variety of feeding mechanisms available to antenna designers such as microstrip line fed, coaxial probe fed, Co-Planar Waveguide (CPW) fed and slot/aperture couple fed, a proper practice to select the best possible feeding mechanism is required. In this paper, an RDRA is used to investigate the performance of different feeding mechanisms-based antenna systems. These feeding techniques give a better understanding of design parameters of an antenna and their effect on return losses, bandwidth, VSWR and resonant frequency. [ABSTRACT FROM AUTHOR]

In this paper, Side Lobe Level Reduction (SLL) and control of beam broadening in beam steered linear array of isotropic radiators with uniform inter-element spacing was investigated. As a solution to the problem of beam broadening with reduced SLL, a novel method was proposed modifying primarily the search space definition in Classical Particle Swarm Optimization (CPSO). In the proposed method, search space for CPSO was defined using different amplitude distributions, namely, Chebyshev distribution, Taylor one parameter distribution and Taylor Chebyshev error distribution. CPSO, with the information of where to search, finds the optimum excitation amplitude within defined search space for achieving both reduced SLL and narrow beam width. As an example, a 16-element linear array was considered to obtain both reduced SLL and beam width narrowing within the beam steering range. The results showed the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The paper presents new Voltage Controlled Oscillator (VCO) designs using three transistors--XOR, XNOR and CMOS inverter. The output frequency was controlled with varying control voltage from 1.8 V to 3.3 V. Three-stage VCO provides the frequency in the range of 4.905 GHz to 6.958 GHz, whereas the power consumption varied in the range of 0.668 mW to 4.462 mW. Five-stage VCO depicts frequency in the range of 2.595 GHz to 3.782 GHz with power consumption variation from 0.987 mW to 6.711 mW. Moreover, a seven-stage VCO achieves the frequency range from 1.791 GHz to 2.648 GHz with power consumption variation from 1.306 mW to 8.96 mW. The phase noise results obtained with 1 MHz offset for three, five and seven-stage VCOs were -86.34 dBc/Hz, -90.849 dBc/Hz and -92.375 dBc/Hz, respectively. The power consumption, output frequency and phase noise results are compared with previously reported circuits, with the proposed circuit designing approach showing considerable improvements. [ABSTRACT FROM AUTHOR]

This paper proposes a new circuit for 1-bit CMOS full adder cell. The proposed adder cell is designed using mixed CMOS static logic style. It provides good Power Delay Product (PDP), less power dissipation and less delay. The performance parameters like number of transistors used, power dissipated, delay and PDP, i.e., energy consumed per element of existing adder cells, are compared with the proposed adder cell. The simulation is carried out using Cadence tool virtuoso spectre simulation and using 45 nm CMOS process technology. The results showed that the proposed cell has better performance parameters and operates at ultra low power supply. [ABSTRACT FROM AUTHOR]

Microstrip antennas are frequently used in wireless applications. They are well known for their beneficial mechanical characteristics like low profile, planar but conformal to nonplanar, easy to fabricate and lightweight. They have flexibility in terms of electromagnetic parameters like gain, radiation pattern and polarization. They are used in the application of spacecraft, missiles and satellites. The paper uses FR4 material of height 1.6 mm to design high gain circular patch antenna array of 2× 2 and 2×4. Simulation of the antenna array was done by High-Frequency Structure Simulator (HFSS) v13.0. HFSS is used for calculation of antenna parameters like gain, return loss, radiation pattern and VSWR of the antenna. [ABSTRACT FROM AUTHOR]

As we evolve towards 5G networks, achieving spectral efficiency and energy efficiency and dealing with interference are among the greatest challenges encountered so far. The paper looks at interference issues and its causes in Heterogeneous Cellular Networks (HetNets) and how they have been combated using different management techniques. It is found that most of these interference management techniques, when applied to HetNets, do improve the performance of HetNets, but could not mitigate dominant interference scenarios in HetNets when frequency reuse-one deployment is employed. Solutions are proffered to these dominant interference scenarios in HetNet. [ABSTRACT FROM AUTHOR]

Survivability is an issue of great concern in high speed networks. Optical Packet Switching (OPS) is an established technique in the area of survivable high speed future networks. In this paper, network performance is evaluated in response to ingress packet size variation. The performance is evaluated for both protocols: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). Analysis is performed on mesh networks for different ingress packet size. Response of both transport layer protocols has been observed under single link failure. Network throughput with TCP is higher as compared to throughput with UDP. Network throughput is highest at 500 byte packet size, which is less than the configured Maximum Segment Size (MSS) of transport layer protocols. [ABSTRACT FROM AUTHOR]

The paper aims at studying the vital factors affecting the beam pattern and analyzing the performance of Direction of Arrival (DOA) estimation algorithms. The information needed to calculate the DOA is obtained by analyzing the wave impinging on the linear array using MATLAB. The performance evaluation of the three directions of arrival estimation (DOA) algorithms namely Delay and Sum, Minimum Variance Distorsionless Response (MVDR) and MUSIC has been done in open space and closed room. Among the three, the MUSIC algorithm has the highest resolution however the need of large number of frames to maintain the accuracy, high computational demands and the number of sources present to be known beforehand are its major limitations. [ABSTRACT FROM AUTHOR]

The common approach to realizing high gain is to use several low gain elements in an array either in linear, rectangular or circular manner. Linear arrays are used for producing narrow beam in plane parallel to the antenna axis, while wider beam in orthogonal plane. Complexities in the practical implementation of arrays make it less attractive to antenna designers. An array of efficient radiators with an efficient feed network and coarse fabrication tolerances would satisfy these requirements. In the paper, first linear array of 4 cylindrical dielectric resonator elements with uniform excitation has been designed and investigated. Later, in the same arrangement, array elements are excited according to Dolph-Chebyshev distribution for a set of optimum beam width and side lobe level. Array has shown beam width of 24o with side lobe level of 18 dB in H-plane with gain of 10 dB, whereas in E-plane, peak of 12 dB has shown beam width of 23o. Tapering in excitation is achieved with the feed network itself and hence no additional element is needed to obtain the different level of excitation. The proposed design with impedance bandwidth of 1 GHz and gain of nearly 12 dB can be used for satellite communication and other wideband wireless applications at X-band. [ABSTRACT FROM AUTHOR]

Rain attenuation is one of the main impairments that limit radio signals in high rain rate regions, especially at higher frequencies such as Ku, K and Ka frequency bands. Therefore, rain rate and rain attenuation predictions are some of the fundamental steps to consider when designing terrestrial line of sight communication links. The paper presents rain rates at 1 min integration for 0.01 percentage of time exceedance using Chebil, Lavergnat-Golé and power law conversion rain rate models for Akungba-Akoko, Ondo State, Nigeria. This was achieved using 5 min integration rainfall data for a period of three years. The rainfall data were measured by the Nigerian Environmental and Climate Observing Program (NECOP) instrumentation installed at the Adekunle Ajasin University, Akungba-Akoko. The estimated rain rates were used as input parameters to compute the total rain-induced attenuation at 0.01 percentage of time exceedance for 15 GHz, 23 GHz and 30 GHz through a path length of 10 km for vertical and horizontal polarizations, using Moupfouma, ITU-R and Lin attenuation models. Lavergnat-Golé conversion model gave the highest rain rate estimation in the region, while Lin attenuation model gave the highest estimation for total rain-induced attenuation, which is also closest to that of the ITU-R attenuation model. Generally, for all operating frequency bands and rain rates, the total rain-induced attenuation at horizontal polarization is higher compared to that at vertical polarization. Results from the analysis provide a broad knowledge of rain attenuation in the tropical region which can serve as a good preliminary design tool for terrestrial link engineers. [ABSTRACT FROM AUTHOR]

Propagation models are required for proper planning of a network and for accurate interference estimation, or else, it could result in networks with high co-channel interference and waste of power. The paper aims at adapting a propagation model that is best suitable for Minna city in Niger State, Nigeria. This is done by modifying some existing empirical propagation models--Free space, Hata, CCIR and Ericsson path loss models--to suit Minna city using VHF television signals of Nigeria Television Authority (NTA) Minna, channel 10. The station transmits at 210.25 MHz for video signal. The signal levels of the transmitted signal were measured along five radial routes from the transmitting station with a digital signal level meter, and Global Positioning System (GPS) was used to measure the corresponding distances. Data processing and computation were carried out using Statistical Package for Social Sciences (SPSS) and Microsoft (MS) Excel software package. The results showed that the Ericsson model gave more accurate prediction for path loss in Minna city after general modification with the correction factor of -38.72 and Root Mean Square Error (RMSE) of 6.34 dB. [ABSTRACT FROM AUTHOR]

High packing density and low power dissipation in a chip are the needs of very large-scale integrated circuits. As technology is shrinking, conducting channels are becoming shorter to add more devices onto the fixed area, but simultaneously certain factors arise which degrade the device performance. To overcome the limitations of short channel MOS transistors, several designs for the device architecture like Double Gate (DG) and Triple Gate (TG) MOS structures have been explored. The paper reviews the performance advantages of each advanced structure and relative dependence on various process parameters. Also, the developed analytical models for calculating drain current, surface potential, transcapacitances, etc., of these structures have been assessed. [ABSTRACT FROM AUTHOR]

Heterogeneous cellular Network (HetNet) is a promising technology for 5th Generation (5G) mobile networks that can potentially improve spatial resource reuse and extend coverage, therefore allowing it to achieve significantly higher data rates than single-tier networks. However, the performance of HetNet is limited by co-channel (inter-UE, inter-cell) interference. Hence, resource allocation is carefully done in this paper to ensure that the loss in achievable data rate due to interference does not diminish the gain in the achievable data rate due to higher spatial reuse. The resources considered are the spatial resource (unit-beamformer) and the power resource. Distributed spatial resource allocation problem is formulated as a quadratic optimization problem with non-convex quadratic constraints and solved by exploiting Karush-Kuhn-Tucker (KKT) conditions. The proposed hybrid power resource allocation scheme involves a three-step process, starting with two power optimization procedures. These two power optimization procedures are formulated as convex optimization problems and solved by exploiting KKT conditions and CVX (a Matlab software for discipline convex programming), respectively, while the third step involves utilizing results from the aforementioned power optimization procedures to compute average powers allocated to UEs. The simulation results of the proposed method, when compared with other existing methods showed significant improvement. [ABSTRACT FROM AUTHOR]

Advancement in information and communication systems leads to next generation wireless networks that should support higher capacity and data rate, low end-to-end latency, low infrastructure cost and high energy efficiency. To support next generation requirements, 5G will be the most prominent network based on massive MIMO (mMIMO). mMIMO has multiple number of antennas that help to fulfill the requirements of 5G, but there are some issues like pilot contamination, hardware impairments, inter-antenna correlation due to space constraints and non-orthogonal waveform design that needs to be rectified for utilizing advantages of mMIMO sufficiently. The paper reviews the various limitations and relevant techniques to solve these shortcomings of 5G wireless network. [ABSTRACT FROM AUTHOR]

The paper proposes a coding scheme for avoiding crosstalk and reducing power consumption. System-on-Chip (SoC) buses are associated with delay, power and reliability problems. Capacitive crosstalk and high power consumption due to various capacitances are the major causes of this problem. Verilog simulation of encoder and decoder modules are designed to avoid these problems. [ABSTRACT FROM AUTHOR]

This paper presents an approach for edge detection using the fuzzy logic and the evolutionary learning techniques such as Bacterial Foraging (BF), Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and Gravitational Search Algorithm (GSA). Detection of edge pixels in color images by fuzzy detectors is the main focus of this paper. In this approach, a circular mask is applied separately on Red (R), Green (G)and Blue (B) components of the RGB color space to compute Univalue Segment Assimilating Nucleus (USAN) (Smith and Brady, 1997) area about every pixel in the image leading to the USAN area image. A histogram-based Gaussian membership function is used to detect the strong edges and the modified bell-shaped function is used to detect the weak edges from this image after fuzzification. Entropy and edge sharpness factors involved in the objective function and the parameters that control the shape and range of the modified bell-shaped function are optimized using different evolutionary techniques. The edge maps of the three color components are obtained by subjecting the fuzzified USAN area images of color components to adaptive thresholding. The final edge map is obtained by combining the edge maps of the above three color components. Experimental results show that this approach is less sensitive to noise without causing edge displacement. Visual and quantitative analyses demonstrate that the proposed method is better than the traditional edge detectors available in literature. [ABSTRACT FROM AUTHOR]

Telecom services signify the social and economic development of a nation. The telecommunications sector is one of the prime sectors required for the transformation and development of a nation. The Indian telecommunications sector has undergone a major process of evolution and progression. The National Telecom Policy was declared in 1994, and was subsequently reformed and carried forward under the National Telecom Policy, 1999. The Indian telecom sector is a spectator to the complete revolutionary transformation due to reformation of various policies in the last decade. It has achieved a phenomenal escalation during the last few years and is poised to take a big leap in the future. This growth has resulted in some adverse effects like accumulation of Green House Gases (GHG), issues in spectrum management and paucity of energy. Increasing public demand for corporate social responsibility and an authentic desire to effect positive change in the environment are leading the telecommunications service providers and their suppliers to diminish their carbon footprint. There are many emerging issues in the management of spectrum like reform of previous regulatory framework, streamlining the Standing Advisory Committee on Frequency Allocation (SACFA) clearances, delicensing spectrum bands for broadband services, spectrum trading and the lack of unique global unified standard. Many industries and institutions are carrying out research for efficient telecommunication infrastructure. This paper focuses on the issues related to energy, environment, spectrum as well as remedies to overcome the challenges. Use of renewable energy resources, effective and transparent spectrum management and one unified standard with convergence of different technologies can be future prospects for the betterment of service providers as well as subscribers. [ABSTRACT FROM AUTHOR]

This paper describes controlled oscillator as a main part of slave clock suitable for synchronization supply, its parameters and their effect on oscillator applicability, particularly in telecommunications equipment. The variables under survey consist of the input phase, the output phase and phase transmission of the timing signal. The paper also deals with questions relating to the band of synchronization. [ABSTRACT FROM AUTHOR]

The Global Positioning System (GPS) has become an important tool in determining the threedimensional position, velocity and time. GPS position accuracy relies on the precise knowledge of the pseudorange measurement from each satellite to the receiver. Multipath is one of the major error sources after ionospheric propagation error that causes a pseudorange error measurement. Multipath can seriously degrade the accuracy of any application that relies on precise measurements, including navigation, surveying and earthquake movement and tsunami detection. This paper presents an analysis of the multipath error estimated on the L1 frequency (1575.42 MHz) of all the GPS satellites that are visible from the Andhra University College of Engineering, Visakhapatnam. We present MATLAB programs for creating colorized polar maps of high-frequency multipath using TEQC report files of single epoch data. The analysis is done using the TEQC toolkit (Estey and Meertens, 1999). TEQC toolkit is used in analyzing the multipath error on the pseudorange observed due to the code and phase on each satellite. The analysis is useful in indicating the actual local direction of multipath on the ground and also gives the orientation with respect to the geometry of the satellites in the sky. This information can aid the interpretation of ground multipath geometry at the site. [ABSTRACT FROM AUTHOR]

The application of signal processing techniques to wireless communications is an emerging area that has recently achieved dramatic improvement in results and The First Generation (1G) and Second Generation (2G) of mobile telephony were indented for voice transmission. The Third Generation (3G) is meant for both voice and data applications. The thirst for effective communication and higher bandwidth has led to the evolution of the next generation wireless systems, and newer technologies are being deployed to provide the user with information and entertainment anywhere and anytime. The 3G mobile radio systems (International Mobile Telecommunication (IMT)-2000 globally and Universal Mobile Telecommunication System (UMTS) in Europe) are becoming a reality today. The network infrastructure is currently being deployed in many countries. Manufacturers, network operators and service providers are now focusing on the development of new services and applications as well as suitable business models to make 3G mobile communication an economic success. One important lesson to be learnt from the development of 3G is that the potential future services and applications, including the expected user behavior should be taken into account from the very beginning to derive the technical requirements. This approach is essential to enable the economic success of future system. The present paper deals with overview of pulse shaping in modern wireless communication in the Wideband Code Division Multiple Access (WCDMA) domain. [ABSTRACT FROM AUTHOR]

This paper addresses physical layer modeling of all the necessary features of 802.16 (d) Worldwide Interoperability for Microwave Access (WiMAX) system. WiMAX system model code has been developed in Matlab to simulate and analyze the performance of a system. Bit Error Rate (BER) performance of the system is analyzed over Additive White Gaussian Noise (AWGN) channel and Rayleigh faded multipath channel. Rayleigh faded channel is modeled using Jakes' sum-of-sinusoids method and Pilot-based channel estimation is employed. Recursive Systematic Convolution (RSC) turbo code is included in the modeling to improve the BER performance. [ABSTRACT FROM AUTHOR]

Orthogonal Frequency-Division Multiplexing (OFDM) can be used in conjunction with a Multiple Input Multiple Output (MIMO) transceiver to increase the diversity gain and/or the system capacity by exploiting spatial domain. The combination of MIMO techniques with OFDM(MIMO-OFDM) is regarded as a promising solution to enhance the data rate of future broadband wireless communication systems. The great finding was that the well-known flat fading MIMO algorithms can be reused on a carrier-by-carrier basis since the channel becomes orthogonal in the frequency domain with OFDM. This reduces the computational effort and makes MIMO-OFDM attractive for mobile applications. The performance of wireless systems is however limited by multipath fading and interference from other users. In MIMO-OFDM systems, instability of transmitter/receiver Radio Frequency (RF) oscillators and the time varying fading channels can destroy the orthogonality of subcarriers. This causes serious Intercarrier Interference (ICI), thus leading to significant system performance degradationwhich becomes more severe as the normalized doppler frequency increases. ICI is a major performance limiter in MIMO-OFDM systems. The ICI cancellation in MIMO-OFDM system is an active area of research. In this paper, a review of ICI cancellation techniques has been presented. [ABSTRACT FROM AUTHOR]

This paper experimentally studies a simple slot-fed Cylindrical Dielectric Resonator Antenna (CDRA). The antenna consists of a Cylindrical Dielectric Resonator (CDR) fed by a microstrip line feed through a coupling slot. The study is carried out by using three antennas with different Dielectric Resonator (DR) thickness and provides dual bands with improved bandwidth. It is observed that the impedance bandwidth increases from 37.09% to 70.9% as the thickness of DR is increased. The return loss and radiation patterns of the proposed antennas are measured and presented. [ABSTRACT FROM AUTHOR]

The paper presents application of Artificial Neural Network (ANN)-based technique for the analysis of aperture coupled feed microstrip patch antenna. Thorough discussion of ANN along with back propagation algorithm has been done. A neural network-based model using back prorogation algorithm was developed with the help of few antennae variable geometrical parameters as inputs and their responses. This trained network is able to locate the resonance frequency for microstrip patch antenna having aperture coupled feed operating within the L (1-2 GHz), S (2-4 GHz), C (4-8 GHz) and partial X-band X (8-10 GHz) bands. These frequency bands are useful for various indoor Wireless Local Area Network (WLAN) applications and little satellite communication respectively. Developed ANN model takes design (geometrical) parameters of antenna like square patch dimension (length = width), length of the slot on the ground plane, width of the slot as inputs and deliver the respective resonance frequency as output within almost no time. The validity of the network is tested with the simulation results obtained from the CST software and experimental result. [ABSTRACT FROM AUTHOR]

The paper describes the design and analysis of CMOS Voltage Controlled Ring Oscillator (VCRO) based on the delay cells proposed by Changzhi and Jenshan (2010). The two-stage CMOS VCRO exhibits very low power consumption and wide tuning range when realized using GPDK 45 nm CMOS process. The design parameters of the transistors in the delay cell are chosen at a minimum scale in this technology so as to achieve the lowest power consumption. The oscillator has a very low power consumption of 2.97 μW with a supply voltage of 1 V. This also exhibits a wide tuning range from 6.4 GHz to 16.4 GHz. Because of its wide tuning range, it can be used for electronic warfare applications. The phase noise of this ring oscillator is found to be -78 dBC/Hz @10 MHz offset which can be improved by increasing the size of the transistors and adding more number of stages. The layout of the VCRO is created using the Cadence virtuoso layout XL tool, which shows that the chip area is 2.82 x 3. 67 μm. [ABSTRACT FROM AUTHOR]

During the handoff process, a mobile station is transferred from one base station to another as a mobile station user moves across the cellular coverage area of a cellular system. Power control is one of the most critical aspects of all cellular systems as all mobile stations operate over battery which has a limited life. Further, safety reasons and interference are also related to power control. Power control and soft handoff are the two essential techniques for effectively increasing the spectral efficiency in a Code Division Multiple Access (CDMA)- based system. Soft handoff and power control exhibit a close relationship in a CDMA-based system. This paper presents an overview and critical analysis of the published work over soft handoff and power control in the downlink direction of a Wideband CDMA (WCDMA) cellular system and discusses the current trends therein. [ABSTRACT FROM AUTHOR]

The antenna required for wireless communication should be lightweight, low cost and small size. This paper presents the design and analysis of microstrip antenna. The proposed antenna offers more wideband as compared to designed rectangular microstrip. Both antennas use microstrip line for feeding purpose. In the present scenario, researchers are aiming at developing a novel design of microstrip antenna which would provide good broadband and gain. The proposed microstrip patch antenna has shown bandwidth improvement with good return loss and also improvement in antenna gain. The well-known technique of rectangular shaped feed line of the square microstrip antenna is changed and the corresponding change in bandwidth and gain of the antenna is compared. Improvement in bandwidth with good return loss and gain of the antenna is also observed. The compact patch antenna is meant to operate in X-band of frequency ranging from 8 to 12 GHz. The proposed microstrip antenna has shown an overall wideband of bandwidth 500 MHz with a peak gain of 10.34, and is very useful in many wireless applications for X-band. [ABSTRACT FROM AUTHOR]

The Long-Term Evolution (LTE) supports peak data rates, higher bandwidth, reduced costs, improved coverage and capacity, integration and backward compatibility with the existing systems. These features are part of LTE-A release. One key feature is carrier aggregation. It refers to aggregation of existing component carriers to provide higher spectrum bandwidth. This supports deployment bandwidth of a maximum 100 MHz and would help to maintain high user data speed of 500 Mbps uplink and 1 Gbps downlink. Bandwidth is very limited and expensive. But by using carrier aggregation, we are depending on existing bandwidth and hence efficiently using it. This paper provides an overview of types, compatibility and simulation results of carrier aggregation for different carriers (Aleksandar et al., 2011). [ABSTRACT FROM AUTHOR]

The increasing demand for wireless communication services without corresponding increase in radio frequency spectrum allocation and better performance motivates the need for new techniques to improve spectrum utilization and system performance which is smart antenna system. The paper presents Least Mean Square (LMS) adaptive algorithm for Smart Antenna (SA) systems. The LMS incorporates an iterative procedure that makes successive correction to the weight vector in the desired direction which eventually leads to Minimum Mean Square Error (MMSE). The LMS algorithm is presented for interference rejection of adaptive array antennas and gives sharper beams directed towards the desired users. The experimental results of LMS are investigated using MATLAB for different jamming angles, message frequency and for number of sensors. The simulation results are useful for mobile applications for reducing noise and interference. [ABSTRACT FROM AUTHOR]

To increase the capacity of an optical fiber, Wavelength Division Multiplexing (WDM) is used which allocates a certain wavelength to each channel. In this paper, the performance of 4- and 8-channel WDM optical network has been analyzed at various channels spacing and for different input powers of CW Lorentzian laser at data rates of 20 Gbps using Modified Duo-binary Return to Zero (MDRZ), Non-Return to Zero (NRZ), Return to Zero (RZ) and Carrier Suppressed Return to Zero (CSRZ) modulation formats. As channels are multiplexed in WDM, dispersion is introduced. In order to overcome this problem, dispersion compensating fibers are used in symmetrical dispersion fiber compensation technique. In this investigation, transmission distance covered is up to 390 km using Single Mode Fiber (SMF) and Dispersion Compensating Fiber (DCF). For performance evaluation criteria, Bit Error Rate (BER), Eye Opening Penalty (EOP) and Quality factor (Q-factor) have been analyzed. [ABSTRACT FROM AUTHOR]

The demand for high speed networks has significantly increased. In order to supply network capacity to attend to this demand, optical networks have been considered as the most reliable and economic solution to provide high transmission rates. High speed network works efficiently with appropriate routing techniques. The objective of this paper is to calculate and compare the performance of static routing techniques and dynamic routing techniques in wired networks. The effect of variations in bandwidth and number of nodes on the network performance are analyzed over a wide range of values. The parameters used for evaluation of performance are throughput, packet loss ratio, average latency and average jitter. Simulations are performed and analyzed in NS-2.35, and it is concluded that dynamic routing protocol shows better results as compared to static routing protocol network sizes considered. As network size increases, dynamic routing proves to be even more efficient. [ABSTRACT FROM AUTHOR]

Free Space Optical (FSO) communication offers a promising technology for future high speed networks by providing huge transmission bandwidth, light weight, small size, low cost, low power and license free deployment as compared to the present radio frequency systems. Since in FSO communication, the atmosphere is used as a channel, atmospheric turbulence effects cause fading and misalignment of signal at the receiver and deteriorate the Bit Error Rate (BER) performance. This paper is focused on analyzing the FSO communication system performance in Delhi by modeling FSO communication system using basic Wavelength Division Multiplexing (WDM) technique with optimizing several system parameters in different turbulent environments such as fog and rain. Performance is analyzed in terms of Signal-to-Noise Ratio (SNR), received optical power and BER for different meteorological effects at data rate of 2.5 Gbps, 5 Gbps and 15 Gbps. From the results, it is concluded that the quality of received signal can be improved with priority-based optimization of parameters that increases link range up to 115 km in clear weather condition at 15 Gbps. [ABSTRACT FROM AUTHOR]

While the transition to 6G network technology has introduced significant advancements in mobile communications, it has also presented challenges to achieving optimal signalinterference-noise-ratio (SINR), especially in urban and suburban environments. This study focuses on SINR distributions within the lower-value spectrum characteristic of 6G environments, with the goal of refining coverage probability models. Through advanced simulations, the study enhanced existing models by considering factors such as antenna heights and signal frequencies. The findings showed a sharp initial increase in coverage probability in urban areas with additional base stations, contrasting with a more linear improvement in suburban areas. Specifically, urban coverage probability improved from 0.60 to 0.77, while suburban coverage saw a gradual increase from 0.50 to 0.63 with increased base station density. The study highlighted the need for tailored 6G deployment strategies to effectively address the unique challenges of urban versus suburban settings. The findings offer valuable insights for network planners and operators in optimizing 6G networks, emphasizing the significance of SINR optimization in achieving high-quality network coverage across different geographical landscapes. [ABSTRACT FROM AUTHOR]

Time Delay Estimation (TDE) between the signals received at the spatial sensor pair has been a topic of significant importance because this estimated delay can be used as input in plenty of applications for further processing of the signal. The estimation of the delay should be accurate enough in order to avoid or minimize the propagation of the error to the subsequent stages. The generalized cross-correlation method is the most popular and widely used technique for TDE due to accuracy and low computational complexity. The paper presents a comparison of weighting functions used in generalized cross-correlation along with their simulation results. It has been shown how each weight affects the peak sharpening in the correlation function. Simulation has been carried out with different types of sound and noise. The effect of varying Signal-to-Noise Ratio (SNR) on the estimated delay has also been studied. [ABSTRACT FROM AUTHOR]

With the advent of satellite-based navigation technology such as Global Positioning System (GPS), the air transport system has seen a dramatic change particularly in the civil aviation sector. To meet the world-class standards of the navigational aids installed at various airports, a detailed investigation of the existing navigational aids and improvement possibilities is the need of the hour. However, the standalone GPS is not commensurate with the requirements of critical navigation guidance as mentioned in Category I (CAT I) Precision Approaches (PAs). Due to the tremendous increase in air traffic, enhancement of the performance of ground and space-based navigational system is essential. Flight accidents occur due to course variations in the navigational aids. Hence, there is a need to improve the accuracy and performance of navigational aids. The performance of GPS is affected by deviational generation points, and the predominant deviation generation point that limits the position accuracy next only to the ionospheric propagation deviation (7-100 m) is the multipath error. This paper presents a new receiver signal processing algorithm, i.e., Isolating Multipath Effects from the Position Estimate Residuals (IMEPER) in GPS receivers to estimate multipath error. [ABSTRACT FROM AUTHOR]

In Wireless Sensor Network (WSN), the life span depends on the energy consumption of the sensor node; reducing the energy consumption of each node in turn increases the lifetime of the network. Clustering is an effective technique to reduce the energy consumption. Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is the first hierarchical cluster-based routing protocol successfully used in the WSN. In this paper, a recent survey of hierarchical routing protocols which are based on LEACH protocol is presented. Specifically, the network lifetime and energy consumption for each protocol is shown and a comparison of these protocols in terms of advantages, disadvantages, communication pattern and energy efficiency is made to identify the research issues to be solved, and an idea for the future proposed routing algorithms of wireless networks based on LEACH routing algorithm is presented. Further, simulation of the LEACH and improved LEACH-CC protocol is done using MATLAB. [ABSTRACT FROM AUTHOR]

An antenna array consists of distributed antenna elements whose outputs are combined in such a way that the parameters of communication system are optimized. A smart antenna is an antenna array system aided by some "smart" algorithms designed to adapt to different signal environments. Through beamforming, smart antennas offer low co-channel interference and large antenna gain to the desired signal, leading to better performance than conventional antenna systems. Since beamforming is performed in software, forming several beams with the same array is possible by simply reusing the array output. The signal received at each antenna element is multiplied by an optimum weight and these products are added to get the desired output signal. The weight vector can be calculated using one of the many adaptive algorithms such as Least Mean Square (LMS) algorithm, Sample Matrix Inversion (SMI) algorithm, Recursive Least Square (RLS) algorithm and their variants. The SMI algorithm has a faster convergence rate since it employs direct inversion of covariance matrix to compute the weights. This paper analyzes how weight vector and beam pattern of the smart antenna system are changing for different angles of arrival of desired signal and also for different number of antenna elements in an antenna array. [ABSTRACT FROM AUTHOR]

Rectangular Microstrip Antenna (RMA) with square notch at its center is designed with an infinite ground and studied for its dual frequency characteristics. A microstrip antenna in its simplest configuration consists of a radiating patch on one side of a dielectric substrate (€r) and a ground plane on the other side. In this paper, substrate (FR4) of permittivity of 4.4 and thickness of 1.6 mm and rectangular patch having dimension of 25.5 × 33.2 mm are used to fabricate microstrip antenna. However, this configuration has a disadvantage--surface waves are formed which reduces the efficiency and gain of RMA. An Electromagnetic Band Gap (EBG) structure is introduced on the other side of substrate which acts as ground plane to suppress the surface wave excited by radiating patch, resulting in the enhancement of gain and efficiency of antenna, named as EBGRMA. For making EBG structure, RMA is modified by etching five columns of holes of dimension 4 × 4 mm on the bottom ground side of patch which has dimension 63.75 × 83 mm. The five columns of square hole have center-to-center distance of 8 mm making up an equivalent EBG structure. Later, a metallic reflector is placed at a distance of 8.5 mm below the bottom side of substrate so that power is reflected and thereby increases the gain and directivity of EBGRMA. Patch is fed by a probe at a coordinate of 4.5 and 5.2 mm. The resonant frequency selected for this research is 2.4 GHz. [ABSTRACT FROM AUTHOR]