An Efficient Scheme for PAPR Reduction of OFDM based on Selected Mapping without Side Information
Saber
Meymanatabadi
Assistant Professor, Department of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
author
Javad
Musevi Niya
Associate Professor, Department of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
author
behzad
mozaffari tazehkand
Associate Professor, Department of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
author
text
article
2012
eng
Orthogonal frequency division multiplexing (OFDM) has become a promising method for many wireless communication applications. However, one main drawback of OFDM systems is the high peak-to-average power ratio (PAPR). Selected mapping (SLM) is a well-known technique to decrease the problem of high PAPR in OFDM systems. In this method, transmitter is obliged to send some bits named side information (SI) for each data block. Such side information causes bandwidth efficiency to be decreased; in addition, incorrect detection of SI in receiver side make whole data block be lost. In this paper, we propose a technique by using linear feedback shift register (LFSR) in which side information bits are not explicitly sent. By considering an OFDM system through the use of 16-QAM modulation as an illustrated example, it is shown that the proposed technique from the view point of bit error rate (BER), probability of detection failure ( Pdf) and PAPR reduction performs very well.
AUT Journal of Electrical Engineering
Amirkabir University of Technology
2588-2910
44
v.
2
no.
2012
1
9
https://eej.aut.ac.ir/article_357_e2326a607b92bb7a3e84107a7b5e31c5.pdf
dx.doi.org/10.22060/eej.2012.357
A New Compact Ultra-wideband Linear Antenna Array for Target Detection Applications
reza
gholami
M.Sc. Student, Department of Electrical Engineering, Babol Noshirvani University of Technology, Babol, Iran
author
Bijan
Zakeri
Assistant Professor, Department of Electrical Engineering, Babol Noshirvani University of Technology, Babol, Iran
author
hossein
Mehrpour Bernety
M.Sc. Student, Department of Electrical Engineering, Babol Noshirvani University of Technology, Babol, Iran
author
text
article
2012
eng
This paper presents a low-cost compact planar microstrip-fed monopole antenna and its four-element array design for ultra-wideband (UWB) wireless communication and target detection applications, respectively, operating in the frequency span of 3 GHz to 11 GHz. A prototype was fabricated and then measured based on optimal parameters. The results of reflection coefficient (S11) and radiation patterns are shown and discussed. There is good consistency between the simulated S11 and the measured one. In addition, a 1 × 4 linear array design with the size of 100 mm × 34 mm has been proposed to achieve a higher gain. Simulation shows that the array gain is increased about 6 dBi in comparison to the single element through the whole UWB frequency range. The proposed array has an average of -15 dB side lobe level (SLL) in the mentioned range. And also, a -23 dB SLL has been achieved by applying Dolph-Chebyshev amplitude distribution at 6 GHz. Simulation results confirm that the antenna exhibits a constant bidirectional radiation pattern with a high and flat gain in case of the array design.
AUT Journal of Electrical Engineering
Amirkabir University of Technology
2588-2910
44
v.
2
no.
2012
11
19
https://eej.aut.ac.ir/article_358_21a3ebc90506c46273dc919be8992447.pdf
dx.doi.org/10.22060/eej.2012.358
Magnetic Saturation Impacts on Fault Analysis of Squirrel-Cage Induction Motors using Winding Function Approach
mansour
ojaghi
زنجان - خ صفا -کوچه شهید علوی - سمت راست - پ 7
author
Mahdi
Sabouri
author
text
article
2012
eng
Multiple coupled circuit modeling of squirrel-cage induction motors, or winding function approach is the most detailed and complete analytical model used to analyze the performance of the faulty induction motors. This paper extends the above-mentioned model to a saturable model including variable degrees of the saturation effects using an appropriate air gap function and novel techniques for locating the angular position of the air gap flux density and for estimating the saturation factor. Comparing simulated and experimental magnetization characteristics and no-load current waveforms, accuracy of the new saturable model is verified. Using saturable and non-saturable models, various simulations are carried out on faulty induction motors, and then, by comparing the results, the impacts of the saturation on the performance of the faulty motor become evident. Also, comparisons are made with the experimental and/or finite elements results, which confirm the higher accuracy of the saturable model versus non-saturable model.
AUT Journal of Electrical Engineering
Amirkabir University of Technology
2588-2910
44
v.
2
no.
2012
21
31
https://eej.aut.ac.ir/article_359_05766be62df74a2b5e049d91807465f6.pdf
dx.doi.org/10.22060/eej.2012.359
Statistical Variation Analysis of Formant and Pitch Frequencies in Anger and Happiness Emotional Sentences in Farsi Language
Davood
Gharavian
Assistant Professor, Department of Electrical Engineering, Shahid Beheshti University, Tehran, Iran
author
text
article
2012
eng
Setup of an emotion recognition or emotional speech recognition system is directly related to how emotion changes the speech features. In this research, the influence of emotion on the anger and happiness was evaluated and the results were compared with the neutral speech. So the pitch frequency and the first three formant frequencies were used. The experimental results showed that there are logical and reasonable relations between the emotions and variations of these speech features. These results were also used to confirm our previous research about emotion recognition and emotional speech recognition.
AUT Journal of Electrical Engineering
Amirkabir University of Technology
2588-2910
44
v.
2
no.
2012
33
45
https://eej.aut.ac.ir/article_361_d0394f6f335b5f4c6db7e187e3fb95a0.pdf
dx.doi.org/10.22060/eej.2012.361
The Development of Maximum Likelihood Estimation Approaches for Adaptive Estimation of Free Speed and Critical Density in Vehicle Freeways
Amin
Ramezani
Assistant Professor, Control and Intelligent Processing Center of Excellence, School of ELec & Comp, Engineering, University of Tehran, Tehran, Iran
author
Behzad
Moshiri
Professor, Control and Intelligent Processing Center of Excellence, School of ELec, & Comp. Engineering, University of Tehran, Tehran, Iran
author
Ashkan
Rahimi Kian
Associate Professor, Control and Intelligent Processing Center of Excellence, School of ELec & Comp, Engineering, University of Tehran, Tehran, Iran
author
text
article
2012
eng
The performance of many traffic control strategies depends on how much the traffic flow models are accurately calibrated. One of the most applicable traffic flow model in traffic control and management is LWR or METANET model. Practically, key parameters in LWR model, including free flow speed and critical density, are parameterized using flow and speed measurements gathered by inductive loop detectors and Closed-Circuit TV. The challenging problem here is continuous changes in these parameters due to traffic conditions (traffic composition, incidents) and environmental factors (dense fog, strong wind, snow) and missing data. In this paper Maximum Likelihood approaches are developed to the LWR model identification while inaccurate observations are available at the traffic control center. A Maximum Likelihood method is accomplished via the employment of an Expectation Maximization algorithm. To approximate first and second derivatives of optimal filter without sticking in analytical complexities, The EM algorithm is implemented based on particle filters and smoothers. Two convincing simulation results for two sets of field traffic data are used to demonstrate the effectiveness of the proposed approaches.
AUT Journal of Electrical Engineering
Amirkabir University of Technology
2588-2910
44
v.
2
no.
2012
47
58
https://eej.aut.ac.ir/article_362_23c0e55fc4378e26726b09dac8c4fb87.pdf
dx.doi.org/10.22060/eej.2012.362
Optimum Design of BrushLess DC Motor with Minimum Torque Pulsation using FEM & PSO
Mojtaba
Pourjafari
M.Sc. Student, Department of Engineering, University of Guilan, Rasht, Iran
author
Esmael
Fallah Choolabi
Assistant Professor, Department of Engineering, University of Guilan, Rasht, Iran
author
mehrdad
jafar bolan
Associated Professor, Department of Electrical Engineering, Malek Ashtar University of Technology, Shahin shahr, Iran
author
text
article
2012
eng
Despite many advantages of BrushLess DC motor, torque pulsation is one of the most important disadvantages of it. At first, an optimum primary design of BLDC motor is done using PSO algorithm. Then, other parameters for reducing the torque pulsation are considered by finite element method. It is shown that fractional slot structure has many advantages than conventional one. Both cogging and ripple torque have been reduced for fractional structure. In the next steps, other important torque pulsation parameters, such as magnet embrace, offset and skew are considered. Proper embrace, skew and offset are achieved for reducing torque pulsation by nonlinear finite-element analysis.
AUT Journal of Electrical Engineering
Amirkabir University of Technology
2588-2910
44
v.
2
no.
2012
59
70
https://eej.aut.ac.ir/article_360_e08ac42ef37b7a597bc79a3a5cd0a9b4.pdf
dx.doi.org/10.22060/eej.2012.360