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Open access

Jamal Zaidouni, Atika Menhaj, Kamal Ghoumid, Slimane Mekaoui, Ali El Moussati and Yassin El Hillali

Abstract

The use of Constant False Alarm Coded Anticollision Radar (CFACAR) is very interesting in automotive environment. Due to the orthogonality properties of used codes this system is most robust to multi-user interferences. The actual version of the receiver called in this paper Single Correlation Receiver (SCR), is not able to detect the targets in very low input Signal to Noise Ratio (SNR). To resolve this problem, we present a new receiver called Averaging Correlation Receiver (ACR), that computes the average of the M later correlations. Then, we developed the expression of detection and false alarm probabilities for the new receiver in mono and multi-user scenarios. These probabilities are used to plot the new Receiver Operating Characteristics (ROCs). They are drawn for different values of input SNR and length M of ACR. There is a suitable value of M, according to some equation, that can be taken to have a good detection (ROCs more perfect). Also, we found that for a fixed SNR, we must increase sufficiently the length M but it is possible only for low relative velocity of the target. For a velocity of 5Km/h with M = 1055, we can lessen the value of the SNR until we reach SNR = -45 dB.

Open access

Petr Dostálek, Libor Pekař and Pavel Navrátil

Abstract

This paper is aimed at the description of hardware design, software equipment and the functionality of the second evolution of the intelligent multipurpose input/output microcontroller converter and control unit designed and assembled by the authors. Preceding stages of the unit development are concisely overviewed first, the deficiencies of which give rise to the primary motivation of this contribution. Then separate hardware parts of the novel unit are described in detail including electronic schematic diagrams. The device firmware and software capabilities are introduced as well. The advantages of the unit are highlighted compared to older versions. Its functionality, performance and efficiency are then verified by a laboratory control-related dynamic responses measurement example. In the contrary to previous evolutions, a more compact hardware design, increased A/D and D/A converter resolutions, added USB communication capability, better and more accurate analog circuits with more advanced operation amplifiers, the use of OLED instead of LCD display, the pulse-width modulated signal generated by the microcontroller unit itself can be considered among the most important improvements. Moreover, the direct use of the serial link may reduce noise significantly and makes the device more universal.

Open access

Seetaiah Kilaru

Abstract

Many software based OFDM techniques were proposed from last half decade to improve the performance of the system. This paper tried to implement the same with Hardware implementation. We created Hardware based MISO platform with OFDM. We implemented Alamouti algorithm on this test bed. The test bed is implemented with the help of Field Programmable Gate Array (FPGA). The test bed is functionalized with the help of FPGA through Xilinx based system generator for DSP. In this paper we considered the 2×1 MISO implementation with Alamouti algorithm. The simulation results showed that BER and SNR are considerably high for MISO than SISO. The results also proved that proposed OFDM based Alamouti implementation for MISO is excellent in all performance criterions.

Open access

S. Baher Safa Hanbali and Radwan Kastantin

Abstract

the well-known range-Doppler coupling property of the LFM (Linear Frequency Modulation) pulse compression radar makes it more vulnerable to repeater jammer that shifts radar signal in the frequency domain before retransmitting it back to the radar. The repeater jammer, in this case, benefits from the pulse compression processing gain of the radar receiver, and generates many false targets that appear before and after the true target. Therefore, the radar cannot distinguish between the true target and the false ones.

In this paper, we present a new technique to counter frequency shifting repeater jammers. The proposed technique is based on introducing a small change in the sweep bandwidth of LFM waveform. The effectiveness of the proposed technique is justified by mathematical analysis and demonstrated by simulation.

Open access

Hemant Patidar, Gautam Kumar Mahanti and Ramalingam Muralidharan

Abstract

This paper presents a comparative analysis of three evolutionary algorithms, namely, Backtracking Search Algorithm, Cuckoo Search Algorithm and Artificial Bee Colony Algorithms for synthesis of a scanned linear array of uniformly spaced parallel half wavelength dipole antennas. Here, antenna parameters, namely Side Lobe Level, reflection coefficient and wide null depth are taken into consideration for comparison between algorithms. In addition to it, statistical parameters, namely best fitness value, mean and standard deviation of the fitness values obtained from algorithms are compared. Mutual coupling that exists among the antenna elements is included in obtaining radiation patterns and the self-impedances along with the mutual impedances are calculated by induced Electro-Motive Force method. Two different examples are shown in this paper to validate the effectiveness of the utilized approach. Although, this approach is applied to a linear array of dipole antennas; this can be utilized for other array geometries as well.

Open access

Radosław O. Schoeneich, Marcin Golański, Michał Kucharski, Marek Franciszkiewicz and Dawid Zgid

Abstract

This paper describes an idea and realisation of hidden data transmision using Tiny Aggregation Covert Channel (TAGCC)in Wireless Sensor Networks. Our solution uses data aggregation mechanism called Tiny Aggregation (TAG). The protocol is based on idea of hidden messages sending without generate additional data packets and encryption. The paper describes details of proposed algorithm and simulation results obtained during testing of the sensor networks with hidden channel TAGCC.

Open access

Weston Mwashita and Marcel Ohanga Odhiambo

Abstract

As more and more Base Stations (BSs) are being deployed by mobile operators to meet the ever increasing data traffic, solutions have to be found to try and reduce BS energy consumption to make the BSs more energy efficient and to reduce the mobile networks’ operational expenditure (OPEX) and carbon dioxide emissions. In this paper, a BS sleeping technology deployable in heterogeneous networks (HetNets) is proposed. The proposed scheme is validated by using extensive OMNeT++/SimuLTE simulations. From the simulations, it is shown that some lightly loaded micro BSs can be put to sleep in a HetNet when the network traffic is very low without compromising the QoS of the mobile network.

Open access

Mariusz Suchenek

Abstract

The acoustic properties of the photoacoustic Helmholtz cell can be improved by conical modification of the duct ends. The cone profile of the duct ends was studied, and according to the previous work, not all modifications of the parameters provide an increase of the Q-factor of the resonator. The aim of this work is to investigate the influence of the conical modification of the duct using a step-approximated model.

Open access

A. Lekova, A. Krastev and I. Chavdarov

Abstract

In the context of learning new skills by imitation for children with special educational needs, we propose Wireless Kinect-NAO Framework (WKNF) for robot teleoperation in real time based on Takagi-Sugeno (T-S) Fuzzy Inference System. The new solutions here are related to complex whole-body motion retargeting, standing body stabilization, view invariance and smoothness of robot motions. The raw depth Kinect data are fuzzified and processed by median filter. The joint angles estimation for motion mapping of Human to NAO movements is based on fuzzy logic and featured angles rather than direct angles are calculated by Inverse Kinematics due to differences in the human and robot kinematics. During the joint angles calculation nonlinearities are observed as a result of ambiguity of Kinect 3D joint coordinates in different offsets. NAO kinematic limitations and nonlinearities in workspace are decomposed and linearly approximated by T-S fuzzy rules of zero and first order that have local support in 2D projections. To prevent the robot to fall down, the center of mass is considered in order NAO to stay within a support and safe polygon. The feasibility of the proposed framework has been proven by real experiments.

Open access

V. Sgurev and S. Drangajov

Abstract

A linear programming model is proposed for interpretation of the problem for allocation of resources between a finite number of consumption stores at which the risks occurring are considered. At that linear constraints are imposed between the resources in the detached points and between the risks occurring at that. Results are obtained related to reducing this problem to a general Linear Programming (LP) program in which optimal solution is sought for minimization of the expenses for allocation of the resources as well as for taking the risks. A numerical realization of the linear model proposed is carried out that confirms the theoretical results received.