Search

A scheme to conformingly combine the electric and magnetic field integral equations (EFIE and MFIE) is presented. Particularly the range space of the method of moments (MoM) matrix system for the mixed discretized MFIE is projected to the range space of the classically discretized EFIE and then combined with EFIE. As a result, an accurate, interior resonance free, and ideally combination factor independent matrix system for the combined field integral equation (CFIE) is obtained. Numerical examples that demonstrate the accuracy and combination factor dependence are presented.

In this study, an application of fuzzy expert system was introduced. This system was designed to determine the level of iron deficiency anemia and thus, expert physicians were provided with a system to assist them to determine an exact diagnosis prior to their treatment. While realizing the system design, the laboratory records obtained from real patients were examined, the appropriate parameters were specified, the input and output parameters were fuzzified and finally the rule base was built with the expert physician. This study used the centroid defuzzification method together with the Mamdani inference mechanism which is often used in the related literature. With the help of a visual programming language, the level of the disease was displayed in a perceptible way as the result of running the system.

In this work, performance of a multiple-input multiple-output dual hop amplify-and-forward relay network, where transmit antenna selection is employed at source and relay for transmission, and receive antenna selection and maximal ratio combining are employed at the relay and destination, respectively for reception, is analyzed over flat and asymmetric Nakagami-m fading channels. In the network, the source communicates with the destination by the help of single relay without source-destination link. The relay applies amplify-and-forward protocol to forward the signal transmitted by the source to the destination. In this paper, we derive closed-form cumulative distribution function, moments and moment generating function of end-to-end signal-to-noise ratio and closed-form symbol error probability expressions for fixed relay gain. We also derive the asymptotical outage probability and symbol error probability expressions to obtain diversity order of the network. Analytical results are validated by the Monte Carlo simulations.

We study the outage probability performance of the transmit antenna selection / generalized selection combining in a dual hop amplify-and-forward relay network over frequency non-selective and slowly Rayleigh fading channel. In the system, source and destination are equipped with multiple antennas; transmit antenna selection and generalized selection combining are employed at the source and destination, respectively. Relay helps the communication between source and destination and is equipped with single antenna. Source-destination link is not available. In this paper, we derive closed form expression of outage probability. Analytical results are supported by the simulations.

In this paper, we propose a new transmit antenna selection scheme based on shadowing side information. In the proposed scheme, single transmit antenna which has the highest shadowing coefficient is selected. By the proposed technique, usage of the feedback channel and channel estimation complexity at the receiver can be reduced. We consider independent but not identically distributed Generalized-K composite fading model, which is a general composite fading & shadowing channel model for wireless environments. Exact closed-form outage probability, moment generating function and symbol error probability expressions are derived. In addition, theoretical performance results are validated by Monte Carlo simulations.

In this work, we propose and study the performance of a new transmit diversity technique called rotation and polarization diversity. In this technique, in-phase and quadrature components of the rotated symbols are transmitted over two different polarizations of polarized transmitted antenna. By this way, in-phase and quadrature components are affected by different fading coefficients. Error performance of the proposed technique is studied over flat, slowly and correlated Nakagami-m fading channels. Analytical results are validated by the simulations results. According to the results, diversity order of the proposed technique is about twice the channel fading parameter.

In this paper, performance of Transmit Antenna Selection / Maximal Ratio Combining (TAS / MRC) in two hop Amplify-and-Forward (AF) relay system is analyzed over frequency non-selective and slowly Rayleigh fading channel. In the system, all nodes are equipped with multiple antennas; TAS is employed at the source and relay for transmission, MRC is employed at the relay and destination for reception. The source and destination communicate by the help of single relay and source-destination link is not available. In this paper, we derive closed form Cumulative Distribution Function (CDF) and Moment Generating Function (MGF) of received Signal-to-Noise-Ratio (SNR). We also derive Symbol Error Probability (SEP) expressions for the considered system. Analytical results are validated by the simulations.

In this paper, performance of joint transmit and receive antenna selection in two hop amplify-and-forward relay system is analyzed over frequency non-selective and slowly Nakagami-m fading channels. In the system, all nodes are equipped with multiple antennas; Transmit Antenna Selection (TAS) is employed at the source and relay for transmission, Selection Combining (SC) is employed at the relay and destination for reception. The source and destination communicate by the help of single relay and source-destination link is not available. In this paper, we derive closed form Cumulative Distribution Function (CDF) and Moment Generating Function (MGF) of received Signal-to-Noise-Ratio (SNR). We also derive Symbol Error Probability (SEP) expressions for the considered system. Analytical results are validated by the simulations.

In this work, performance of transmit antenna selection / maximal ratio combining in a two hop amplify and forward relay system is analyzed for frequency non-selective and slowly Nakagami-m fading channels when the fading parameters of two hops are different. In the system, tranmit antenna selection at the source and maximal ratio combining at the destination are employed. Source and destination communicate by the help of single relay which is equipped with single transmit and single receive antenna. The relay amplifies and forwards the received signal from the source to the destination. Analytical results are validated by the simulations. According to the results, diversity order of this technique is about minimum of multiplicaiton of fading parameter in the first hop with number of antennas in the source and multiplicaiton of fading parameter in the second hop with number of antennas in the destination. With this technique, error performance of the system is improved significantly.

In this work, we propose a new transmit diversity technique which we call rotation and space diversity. In this technique, in-phase and quadrature components of the rotated symbols are transmitted by two transmitter antennas such that they are affected by different fading coefficients and received by single receiver antenna. Error performance of the proposed technique is studied over frequency non-selective slowly Nakagami-m fading channels. Analytical results are validated by the simulations. According to the results, diversity order of the proposed technique is the sum of diversity orders of channels from the transmit antennas to the receive antenna and with this technique error performance of the system is improved significantly.

In this paper rotation of signal constellation together with component interleaving is applied to the original PSK scheme and performance of rotated Phase Shift Keying (PSK) scheme is analyzed over frequency non-selective slowly Nakagami-m fading channels. Then we obtained optimum rotation angles for M-PSK, M = 2,4,8. Numerical and simulation results show that Rotated PSK outperforms unrotated PSK over frequency nonselective slowly Nakagami-m fading channels considerably. Results show that rotation provides diversity order of about two for Nakagami-m fading channels.

In this paper, the improvements in Symbol Error Probability (SEP) / Bit Error Probability (BEP) performances of rotated Phase Shift Keying (PSK) modulation are studied over Nakagami-m fading channels. Optimum rotation angles are obtained by the simulations, for different m values over frequency nonselective Nakagami-m slowly fading channels.

In this paper, improvements in Symbol Error Probability (SEP) / Bit error Probability (BEP) performance of rotated Phase Shift Keying (PSK) modulation using receive antenna diversity (combining) techniques are studied over frequency nonselective Nakagami-m slowly fading channels. Optimum rotation angles are obtained by the simulations. Effects of the rotation of signal consellations on the Combining Techniques (CT) are studied.