Beamforming for Relay Assisted MIMO

In cellular wireless communication systems, the current and future networks are promising to provide multimedia services at the cell edges and beyond the cell boundaries efficiently and cost effectively. The relay assisted MIMO networks have got much attraction to meet the requirements by providing high capacity, link reliability and high quality of service. The performance of the relay assisted networks is maximized by making the use of beamforming design at the relay nodes. This chapter describes the recent developments in relay beamforming design for Amplify-and-Forward (AF) relay networks and introduces a new beamforming scheme to improve the network performance in terms of ergodic capacity. The chapter contributes in introduction to basic MIMO channel, various relaying strategies and introduction to relay assisted network topologies. It is followed by critical literature review on AF beamforming techniques. This leads towards the novel and efficient relay beamforming design, its performance evaluation and validity by comparing with various available beamforming techniques.

Review on 60GHz Low Noise Amplifier for Low Power and Linearity

In the extremely high frequency radio spectrum of 30-300 GHz, the band from 57-64 GHz has been de-regulated. The biggest challenge in designing products at this frequency is the design of CMOS based transceiver circuit components. This chapter deals with the review of 60 GHz LNA design. LNA was chosen as this is the first component of the receiver circuit and its performance affects the transceiver efficiency. In this chapter the review is done on 60GHz LNA's design addressing the linearization, and low power challenges. To address these challenges, in literature there are many LNA architectures such as simple cascode topology, Current reuse topology etc. The major advantage of current reuse topology is its load transistor shares the same bias current of driver which results in reduced power dissipation by maintaining the maximum gain. The main objective of this chapter is to address gain, power dissipation and linearization challenges by reviewing the different current reuse architectures and linearization techniques used to implement 60GHz LNA.

Study of Some New Topologies and Associated Techniques Used for the Achievement of Planar Filters

This chapter will treat firstly a summary of the filters synthesis by using Butterworth and chebyshev techniques. After that, a second part will be devoted to the design of planar filters using different techniques; this section will present some examples in bibliography. The aim of this part is to understand the different methods and steps followed to design planar filters, in the same time to discover and to define the different parameters which characterize a filter structure. Therefore, we have chosen some new research studies on low pass filers. The last part will present our contribution in designing planar filter. The first filter structure is a dual bandpass microstrip filter operating for DCS and Wimax applications, this section will introduce the different steps followed to achieve such filter. The second circuit is a novel design low cost microstrip lowpass filter with a cutoff frequency of 2.3 GHz. At the end, we will present a transformation of the microstrip filter to a CPW lowpass filter making it easy for integration with passive and active microwave components.

IP-CHOCK Reference Detection and Prevention of Denial of Service (DoS) Attacks in Vehicular Ad-Hoc Network

Vehicular Ad-Hoc Network (VANET) is a subset of Mobile Ad-Hoc Network (MANET) and it is considered as a substantial component of Intelligent Transportation System (ITS). DoS attacks on VANET are varying and may be overwhelmed by VANET protocols, such as TCP or UDP flooding attacks. Different secure communications models can be used to detect and prevent IP spoofing DoS attacks, by which the attacks are committed by fraudulent and malicious nodes. In this chapter, an efficient detection method has been proposed to detect UDP flooding attacks, called Bloom-Filter-Based IP-CHOCK (BFICK). A prevention method using IP-CHOCK has also been proposed to prevent DoS, called Reference Broadcast Synchronization (RBS). In principle, the combined method is based on the IP-CHOCK filter concept of packets during an attack incident and with busy traffic condition. Fake identities from malicious vehicles can be analyzed with help of the existing reliable IP addresses. Beacon packets were exchanged periodically by all the vehicles to announce their presence and to forward it to the next node.

Automatic Target Recognition from Inverse Synthetic Aperture Radar Images

In this chapter, Inverse Synthetic Aperture Radar, a special type of active microwave synthetic aperture radar is introduced and its applications in military surveillance are presented. Then, the basic principles involved in data acquisition and image generation are explained. The issues and challenges involved in processing the ISAR images for autonomous target detection and identification are discussed later. The proposed classification method is explained and its accuracy is evaluated experimentally against the conventional classification method in the rest of the chapter.

Adaptation of Winlink 2000 Emergency Amateur Radio Email Network to a VHF Packet Radio Infrastructure

This chapter presents software and hardware solutions for interconnecting an existing VHF amateur packet radio infrastructure with ‘Winlink 2000' radio email network. Having in mind that a number of households, schools, and offices are equipped with Internet connections, and that many radio amateurs at such locations are active on their VHF (or UHF) digital networks on a daily basis, the connectivity between the two systems will increase the chances for citizens who suffer after disasters such as earthquakes, heavy rains and floods, followed by malfunction in commercial communicating services – to remain electronically wired with the rest of world by email. The chapter provides a tutorial on constructing, installing, and testing a simple packet radio repeater station, additionally equipped with computer programs with ‘Winlink 2000' compatibility.

Microwave Power Protectors

In this chapter, microwave power attenuator and limiter theory and technological realization are presented. The chapter is divided in two sections, first section is dedicated to attenuator circuits and the second section is dedicated to power limiters circuits. Authors describe, in first section, principles characteristic and fundamentals of attenuator and detail of the most common topologies such as T-attenuator, PI-attenuator and bridged-attenuator. After a presentation of important equations needed to calculate attenuation rate provided by each of these previous cited topologies, authors present the variable attenuator based on active component (PIN diode, Transistors). In second section, authors present power limiter characteristic and fundamentals. Afterward, they present a state of arts of technological solution to design power limiter based on solid state components such as PIN diode and Schottky diodes.

The Design of New Structures of Planar Diplexers Using Microstrip Resonators

In this chapter, three planar diplexers based on microstrip resonators are presented. An overview on diplexers is introduced. Then, two designed and fabricated microstrip diplexers with compact size and good performances are exposed. The first diplexer is designed using open loop resonators while the second circuit is achieved based on triangular loop resonators. The third structure represents a compact diplexer designed by using a pair of H-shaped resonators coupled with a coupling patch and two Input/Output (I/O) feed lines. The incorporated slots in the ground plane of the proposed circuit allow the control of the resonant frequencies and enhance its electrical performances. Furthermore, the introduction of these slots represents an interesting solution to miniaturize the microwave filter and diplexer. An analytic method is applied to extract the equivalent LC model of the band pass filters and diplexer. A full wave electromagnetic Analysis is achieved to evaluate the electrical performances of the proposed diplexers by using ADS and CST-MWS.

Developments in Efficient Antenna Designs Using EBG Structures

Since 2002, when the Federal Communication Commission (FCC) released the bandwidth 3.1-10.6 GHz, there has been increasing interest in the use of UWB systems because of their low power consumption, low cost, precise positioning and promising candidate for short-range high-speed indoor data communications. Planar circular monopoles like designs are a good example for UWB applications due to their merits such as ease of fabrication, Acceptable radiation pattern, and large impedance bandwidth. However, some narrowband systems also operate in this frequency like WiMAX, WLAN and X-Band satellite downlink communication band etc. cause interference in UWB range. To overcome any interference with these systems it is desirable to design UWB antenna with band notches. However, most techniques of obtaining notches uses antenna design specific approaches therefore EBG structures can be used to obtain single and multi-notch antennas. The technique used for obtaining notches using EBG is antenna design independent and can be applied to most of the antennas without compromising antenna performance.

An Accurate and Efficient Analytical Method to Extract the Parameters of the Single and Double Diode Photovoltaic Cells Models

For Photovoltaic systems designers and manufacturers, it is very important to develop suitable models to closely emulate the characteristics of PV cells, predict their behavior and evaluate their efficiency. So the main contribution of this chapter is to propose an improved and accurate method for identifying and determining the equivalent circuit elements values of photovoltaic module using only exact analytical equations and four manufacture's data reference, i.e., the open-circuit voltage (VOC), the short-circuit current (ISC), the current and the voltage at the maximum power point (IM, VM). In order to extract the five-parameter Single or Double-Diode models of photovoltaic module, the authors try initially to determine analytically all parameters according to RS (the value of the series resistance). Thus, all these parameters are calculated once RS is determined. Rapid and iterative algorithm is then designed to solve a strongly nonlinear equation in order to extract the value of RS in a precise manner and without any mathematical simplification used usually by many other authors.