10,109 research outputs found
Development of a dc-ac power conditioner for wind generator by using neural network
This project present of development single phase DC-AC converter for wind
generator application. The mathematical model of the wind generator and Artificial
Neural Network control for DC-AC converter is derived. The controller is designed to
stabilize the output voltage of DC-AC converter. To verify the effectiveness of the
proposal controller, both simulation and experimental are developed. The simulation and
experimental result show that the amplitude of output voltage of the DC-AC converter
can be controlled
Modeling of Orthogonal Frequency Division Multiplexing (OFDM) for Transmission in Broadband Wireless Communications
Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier modulation technique that provides high bandwidth efficiency because the carriers are orthogonal to each other and multiple carriers share the data among themselves. The main advantage of this transmission technique is its robustness to channel fading in wireless communication environment. This paper investigates the effectiveness of OFDM and assesses its suitability as a modulation technique in wireless communications. Several of the main factors affecting the performance of a typical OFDM system are considered and they include multipath delay spread, channel noise, distortion (clipping), and timing requirements. The core processing block and performance analysis of the system is modeled usingMatlab
A Link Quality Model for Generalised Frequency Division Multiplexing
5G systems aim to achieve extremely high data rates, low end-to-end latency
and ultra-low power consumption. Recently, there has been considerable interest
in the design of 5G physical layer waveforms. One important candidate is
Generalised Frequency Division Multiplexing (GFDM). In order to evaluate its
performance and features, system-level studies should be undertaken in a range
of scenarios. These studies, however, require highly complex computations if
they are performed using bit-level simulators. In this paper, the Mutual
Information (MI) based link quality model (PHY abstraction), which has been
regularly used to implement system-level studies for Orthogonal Frequency
Division Multiplexing (OFDM), is applied to GFDM. The performance of the GFDM
waveform using this model and the bit-level simulation performance is measured
using different channel types. Moreover, a system-level study for a GFDM based
LTE-A system in a realistic scenario, using both a bit-level simulator and this
abstraction model, has been studied and compared. The results reveal the
accuracy of this model using realistic channel data. Based on these results,
the PHY abstraction technique can be applied to evaluate the performance of
GFDM based systems in an effective manner with low complexity. The maximum
difference in the Packet Error Rate (PER) and throughput results in the
abstraction case compared to bit-level simulation does not exceed 4% whilst
offering a simulation time saving reduction of around 62,000 times.Comment: 5 pages, 8 figures, accepted in VTC- spring 201
A comparison of digital transmission techniques under multichannel conditions at 2.4 GHz in the ISM BAND
In order to meet the observation quality criteria of micro-UAVs, and particularly in the context of the Β« TrophΓ©e Micro-Drones Β», ISAE/SUPAERO is studying technical solutions to transmit a high data rate from a video payload onboard a micro-UAV. The laboratory has to consider the impact of multipath and shadowing effects on the emitted signal. Therefore fading resistant transmission techniques are considered. This techniques paper have to reveal an optimum trade-off between three parameters, namely: the characteristics of the video stream, the complexity of the modulation and coding scheme, and the efficiency of the transmission, in term of BER
Visualization on colour based flow vector of thermal image for movement detection during interactive session
Recently thermal imaging is exploited in applications such as motion and face detection. It has drawn attention many researchers to build such technology to improve lifestyle. This work proposed a technique to detect and identify a motion in sequence images for the application in security monitoring system or outdoor surveillance. Conventional system might cause false information with the present of shadow. Thus, methods employed in this work are Canny edge detector method, Lucas Kanade and Horn Shunck algorithms, to overcome the major problem when using thresholding method, which is only intensity or pixel magnitude is considered instead of relationships between the pixels. The results obtained could be observed in flow vector parameter and the segmentation colour based image for the time frame from 1 to 10 seconds. The visualization of both the parameters clarified the movement and changes of pixel intensity between two frames by the supportive colour segmentation, either in smooth or rough motion. Thus, this technique may contribute to others application such as biometrics, military system, and surveillance machine
Multiuser MIMO-OFDM for Next-Generation Wireless Systems
This overview portrays the 40-year evolution of orthogonal frequency division multiplexing (OFDM) research. The amelioration of powerful multicarrier OFDM arrangements with multiple-input multiple-output (MIMO) systems has numerous benefits, which are detailed in this treatise. We continue by highlighting the limitations of conventional detection and channel estimation techniques designed for multiuser MIMO OFDM systems in the so-called rank-deficient scenarios, where the number of users supported or the number of transmit antennas employed exceeds the number of receiver antennas. This is often encountered in practice, unless we limit the number of users granted access in the base stationβs or radio portβs coverage area. Following a historical perspective on the associated design problems and their state-of-the-art solutions, the second half of this treatise details a range of classic multiuser detectors (MUDs) designed for MIMO-OFDM systems and characterizes their achievable performance. A further section aims for identifying novel cutting-edge genetic algorithm (GA)-aided detector solutions, which have found numerous applications in wireless communications in recent years. In an effort to stimulate the cross pollination of ideas across the machine learning, optimization, signal processing, and wireless communications research communities, we will review the broadly applicable principles of various GA-assisted optimization techniques, which were recently proposed also for employment inmultiuser MIMO OFDM. In order to stimulate new research, we demonstrate that the family of GA-aided MUDs is capable of achieving a near-optimum performance at the cost of a significantly lower computational complexity than that imposed by their optimum maximum-likelihood (ML) MUD aided counterparts. The paper is concluded by outlining a range of future research options that may find their way into next-generation wireless systems
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