In this paper, the near-far resistance of the minimum mean square error (MMSE) detector is derived for the multicarrier direct sequence code division multiple access (MC-DS-CDMA) communication systems. It is shown that MC-DS-CDMA has better performance on near-far resistance than that of DS-CDMA

Synthesizing arrays with low sidelobe and pencil beam radiation profile is under investigation for decades. A variety of array structures are available, but the simplest and useful structure is that of a linear array. Here, two basic symmetric Linear Antenna Array structures are assumed. The required array structure is assumed to provide low sidelobe and pencil beam profile. Departure from a uniformity in current and location profile has shown quiet appreciable improvement in the radiation pattern. The simulations are carried out using Differential Evolution Algorithm employing Best of Random mutation strategy (DEBoR).

Nonlinear dynamics of a third order phase locked loop (PLL) using a resonant low pass filter in the face of continuous wave (CW) and frequency modulated (FM) input signals is examined. The role of design parameters of the loop resonant filter and the modulation index of the input FM signal on the system dynamics is studied numerically as well as experimentally. The occurrence of chaotic oscillations in the PLL is verified by evaluating some well-known chaos quantifiers like Lyapunov Exponents from the numerical time series data

In this paper, we propose a novel joint semi-blind channel and data estimation technique based on Whitening Rotation (WR) method for Rayleigh flat fading Multiple Input Multiple output (MIMO) channel using different receiver antennas combinations. Here we divide newly proposed technique in three steps. In the first step, we use conventional Whitening Rotation based semi-blind channel estimation technique, where MIMO channel matrix H can be decomposed as H=WQ H . Whitening matrix W can be estimated blindly using second order statistical information of received data and unitary rotation matrix Q can be estimated exclusively using Orthogonal Pilot Maximum Likelihood (OPML) algorithm. In the second step, data symbols can be estimated using estimated channel H and received output data by applying maximum likelihood data estimation method. Finally in the third step, Q can be re-estimated as a Q new using OPML algorithm by considering estimated blind data symbols itself as a pilot symbols for more statistical information of unitary matrix and perform final channel estimation H final=W Q new H . Simulation results are presented under 4-PSK data modulation scheme for two transmitters and different combinations of receiver antennas to support proposed novel technique and they demonstrate improved BER performance compared to conventional WR based optimal technique and Rotation Optimization Maximum Likelihood (ROML) based suboptimal semi-blind channel estimation technique.

In this paper, an evolutionary optimization technique, Particle Swarm Optimization with Constriction Factor and Inertia Weight Approach (PSOCFIWA) is adopted for the complex synthesis of three-ring Concentric Circular Antenna Arrays (CCAA) with non-isotropic elements and without and with central element feeding. It is shown that by selection of a fitness function which controls more than one parameter of the array pattern, and also by proper setting of weight factors in fitness function, one can achieve very good results. For each optimal design, optimal current excitation weights and optimal radii are determined having the objective of maximum Sidelobe Level (SLL) reduction. The extensive computational results show that the CCAA designs having central element feeding with non-isotropic elements yield much more reduction in SLL as compared to the same not having central element feeding. Moreover, the particular CCAA containing 4, 6 and 8 number of elements in three successive rings along with central element feeding yields grand minimum SLL (-46.4 dB). Standard Particle Swarm Optimization (PSO) is adopted to compare the results of the PSOCFIWA algorithm.

The performance of M-ary optical code division multiple access (OCDMA) is analytically investigated in presence of chromatic dispersion. The study is carried out for single mode dispersion shifted and non dispersion shifted fibers. Walsh code is used as user address. The p-i-n photodetector is used for optoelectronic conversion process. In our proposed model 16 different symbols are modulated with different intensity levels and detected by direct detection technique. The numerical results show that, the reconstruction of the transmitted symbol is strongly dependent on the received symbols magnitude which is reduced by fiber length and symbol rate. It is found that the proposed OCDMA system shows better performance when dispersion shifted fiber is used as a communication medium.

In this paper, UWB technology operating in broad frequency range of 3.1-10.6 GHz has shown great achievement for high- speed wireless communications. to satisfy the UWB system requirements, a band pass filter with a broad pass band width, low insertion loss, and high stop-band suppression. UWB band-pass filter (BPF) with wireless local area network (WLAN) notch at 5.8 GHz and 3-dB fractional bandwidth of 108% using a microstrip structure is presented. Initially a two transmission pole UWB band pass filter in the frequency range 3.1-10.6 GHz is achieved by design a parallel-coupled microstrip line with defective ground plane structure using GML 1000 substrate with specification: dielectric constant 3.2 and thickness 0.762 mm at centre frequency 6.85 GHz. In this structure a ë/4 open circuited stub is introduced to achieve the notch at 5.8 GHz to avoid the interference with WLAN frequency with lies the desired UWB band. The design structure was simulated on electromagnetic circuit simulation software and fabricated by microwave integrated circuit technique. The measured VNA results show the close agreement with simulated results.

An innovative data-acquisition circuit for temperature monitoring and control is designed and interfaced to printer port of a web server computer. Further, an interactive web application program has been developed and kept running in the server computer for controlling the operation of the data-acquisition circuit. Authenticated clients can access the web based instrumentation system through Internet / Intranet

This paper presents a novel low profile inverted-F- L antenna (IFLA) for worldwide interoperability for microwave access (WiM AX) applications by means of numerical simulation. The antenna has compact size of 9×20 mm2 and provides a wide bandwidth of 750 MHz (5150~5900 MHz) which covers the 5.5 GHz WiMAX applications. Moreover it has very high peak gain of 8.04 dBi with 1.38 dBi gain variation within the 10 dB return loss bandwidth. The VSWR of the proposed IFLA varies from 1.79849 to 1.91245 within the antenna 10 dB return loss bandwidth. The antenna provides peak return loss of -29.903 dB at 5.45 GHz and the input impedance of proposed IFLA is 47.8595 at 5.5 GHz.

This paper represents the numerical simulations of high gain inverted-F and loaded inverted-F antennas (IFA) for WLAN/Wi-Fi applications. The dimensions of the anten- nas are 16×34, 21×34 and 26×34 mm2 in case of IFA, slightly loaded IFA (SLIFA) and heavily loaded IFA (HLIFA) respec- tively. The antennas contain a very good peak gain of 7.89, 8.11 and 8.15 dBi with less than 1.2, 1.0 and 0.8 dBi gain varia- tion within the -10 dB return loss bandwidth for IFA, SLIFA and HLIFA respectively. Moreover the proposed antennas can provide more than the required bandwidths for WLAN/Wi-Fi operations at 2.4 GHz (2.4~2.484 GHz) band. In addition, the proposed antennas have achievable return loss and radiation characteristics. Due to the compactness of the antennas, they are promising to be embedded within the different portable devices employing WLAN/Wi-Fi applications.

The paper studies the dynamics of a conventional positive going zero crossing type digital phase locked loop (ZC1-DPLL) taking non-ideal responses of the loop constituent blocks into account. The finite width of the sampling pulses and the finite propagation delay of the loop subsystems are properly modeled mathematically and the system dynamics is found to change because of their influence considered separately. However, when these two are taken simultaneously, the system dynamics can be made nearly equivalent to that of the ideal system. Through an extensive numerical simulation a set of optimum parameters to overcome design limitations have been obtained.

The popularity of compact sized antennas are increasing recently due to their significant properties such as, tiny size, high gain, impedance merely 50 and ! and very low phase difference. To achieve this goal, in this paper a Triple Inverted-F Antenna (TIFA) is designed for the 5 GHz WLAN and Bluetooth applications and it operates between the wide frequency ranges 4.75-8.2 GHz. This antenna also provides lower gain variation with peak return loss of -35.14, -25.795 and -22.37 dB at 5.2, 5.5 and 5.8 GHz respectively. In addition, the size of the antenna is only 12×20 mm2.

Network-on-chip (NoC) is a new aspect for designing of future System-On-Chips (SoC) where a vast number of IP cores are connected through interconnection network. The communication between the nodes occurred by routing packets rather than wires. It supports high degree of scalability, reusability and parallelism in communication. In this paper, we present a Mesh routing architecture, which is called Diametrical 2D Mesh of Tree, based on Mesh-of-Tree (MoT) routing and Diametrical 2D Mesh. It has the advantage of having small diameter as well as large bisection width and small node degree clubbed with being the fastest network in terms of speed. The routing algorithm ensures that the packets will always reach from source to sink through shortest path and is deadlock free.

The rapid growth in electronics, sensors and communication technology has made it possible to construct the WSN consists of large number of portable sensors. Because of this measurement accuracy of various parameters in the field has been increased. It has increased the quality of WSN. But due to the use of large numbers of portable sensor nodes in WSN, probability of sensor node failure gets increased. It has affected the reliability and efficiency of WSN. To maintain the high quality of WSN, detection of failed or malfunctioning sensor node is essential. The failure of sensor node is either because of communication device failure or battery, environment and sensor device related problems. To check the failed sensor node manually in such environment is troublesome. This paper presents a new method to detect the sensor node failure or malfunctioning in such environment. The proposed method uses the round trip delay (RTD) time to estimate the confidence factor of RTD path. Based on the confidence factor the failed or malfunctioning sensor node is detected. Hardware based simulation result indicates the easy and optimized way of detecting failed or malfunctioning sensor node in symmetrical WSN