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This paper deals with the case of secure wireless multicasting through multiple-input multiple-output (MIMO) radio system in which two co-existing users communicate with two groups of receivers in the presence of multiple eavesdroppers. Calculation of the secrecy multicast capacity of each group shows the impact of co-channel interferences (CCI) on it. Application of zero-forcing (ZF) or selective...
This paper presents a novel technique to enhance the robustness of space–frequency block coded (SFBC) orthogonal frequency-division multiplexing (OFDM) systems. The proposed system shapes the channel matrix of a frequency-selective fading channel into a piecewise flat fading over each block of two adjacent subcarriers. Analytical and simulation results show that the proposed scheme substantially outperforms...
In this paper, we provide a new approach based on Fourier series model with time varying coefficients for received signal in ultra short pulse or ultra wide band (UWB) radar using an MMSE estimator for estimating the Fourier coefficients that determine the velocity and range of a moving target without appealing to a matched filter. We demonstrate that it is impossible to determine velocity of a target...
Ultra-wideband (UWB) technology is a new concept in wireless short-range communication. It has numerous advantages that are resulted in producing different new products in various applications. This technology uses very short duration pulses hence occupies very large transmission bandwidth. This phenomenon may cause harmful interference in the existing wireless devices. The main objective of this...
The Global Positioning System (GPS) provides special features which can be utilized for wide range of applications. By providing information such as location, direction and speed, GPS is traditionally used for navigation. Nowadays many more applications, from farming, surveying to incident detection in fact fully utilized the GPS. This study accesses GPS signal and determines vehicle location and...
This paper presents the design of a reconfigurable successive approximation analog to digital converter (ADC) for both ultra wideband and Bluetooth applications. The behavioral level design is presented along with the circuit implementation. The ADC architecture employs a split capacitor array DAC which reduces the power consumption. The ADC is implemented in a 0.18mum CMOS process and circuit level...
The discovery of randomness in apparently predictable physical systems have evolved into a new science, the science of chaos. Chaotic systems are unstable and aperiodic, making them naturally harder to identify and to predict. Recently, many researchers have been looking at ways to utilize the characteristics of chaos in communication systems and have actually achieved quite remarkable results. This...
In this paper we investigate the ionospheric GPS-TEC observations at New Zealand Scott Base Antarctica (GC: 77.9degS, 166.8degE, CGM: 79.94degS 327.63degE) during the year 2004. Our results and discussions will include the daily TEC variations, diurnal TEC and statistical analyses.
The ionospheric TEC and scintillation measurements were investigated at ARAU, Malaysia station based on GPS measurements during major storm on 15-16 May 2005. The major storm was observed for the period from 12 to 17 May 2005 and was accompanied by a moderate solar activity with F10.7 > 100 and SSN > 100. The maximum readings of geomagnetic indices Dst, Kp and Ap recorded by the World Data Centre...
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