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The following topics are dealt with:optical wireless communication; signal processing; photonics communications system; wireless sensor network; security; cryptography; ad hoc network; teletraffic models; computer networks; channel coding; channel equalisation; image processing; antenna; chaos and optimisation.
Emphatic phonemes are an important and unique subset of Arabic phonemes. These phonems are difficult to pronounce especially for non-native Arabic speakers and for many normally-educated Arabs. In Arabic, all emphatic phonemes have their own non-emphatic counterparts. In this work, acoustic analysis for the four pairs of emphatic/non-emphatic pairs in Modern Standard Arabic (MSA) is carried out. Formant...
SincN FIR filters are used in a number of digital signal processing applications. They are constituted of a cascade of N sinc filters, each of length M. Straightforward recurrence relations for fast computation of the impulse response coefficients can be derived using Z-Transform techniques. A simple general expression, valid for all the filter coefficients, can be obtained as well. Moreover, generating...
In this paper a new least mean square (LMS) based adaptive weighting algorithm is proposed. It is appropriate for antenna array systems with moving targets and mobile applications. The essential goal of this algorithm is to reduce the complexity of weighting process and to decrease the time needed for adjusting the antenna radiation pattern. The main lobe of antenna will be adjusted in the direction...
A thorough comparison is made between the different implementation schemes of Space-Time and Space-Frequency Block Coded OFDM, showing the features of each alternative, and suggesting typical situations where it excels. New designs are also introduced to complete the comparison set. The issue of mixing diversity modes is addressed, too.
Spectrally Efficient Frequency Division Multiplexing (SEFDM) system promises bandwidth savings by multiplexing overlapped non-orthogonal sub-carriers. Work in the literature has confirmed that despite the non-orthogonal structure of the sub-carriers, efficient detection of the SEFDM signal is achievable. However, loosing orthogonality brings along many design and implementation challenges. In particular,...
This paper present a novel feature selection method based on a ensemble of optimal wavelet packet and learning machine (OWLM). First, the lifting schemes (LS) are used to construct a single decomposition stage of the wavelet transform (WT), these schemes are a fast and flexible implementation for the WT. Then the update and predictor operator of the LS are optimized by Genetic Algorithms (GA) and...
In a communication system the receiver has to be synchronized to the incoming data signal in order to rebuild the transmitted data. Therefore a timing recovery circuit is necessary. Most known implementations of this feature assume that in a digital receiver the samples are processed one after another. This is not true for high speed receivers that are clocked at some stage with a rate less than the...
This paper proposes a fast and efficient multi-processor architecture for devices a requiring high speed performance. The proposed method connects four basic processor modules (BPM) including CPU's in a pipeline shape to enhance execution speed. Also, using a specific BPM selectively regarding to multimedia applications increases the efficiency, and has more flexibility by software implementation...
Accommodating of future demand uncertainty is an important issue in IP networks to continue at acceptable level of service during high traffic load periods. This aspect should also be considered during optical backbones design for high-speed client networks. This paper presents an intelligent fuzzy adaptive approach for spare bandwidth management in Dense Wavelength Division Multiplexing (DWDM) optical...
In communication systems which transmit a continuous stream of data, the coded data symbols are typically transmitted in frames. Frames contain one or multiple blocks of coded data. The Start Of a Frame (SOF) is especially required to synchronize the decoder, especially in systems which use modern codes such as Turbo codes. This process is known as frame synchronization. We examine the general problem...
The collision probability experienced by each node on a link plays an important role in estimating the available bandwidth at the Medium Access Control (MAC) layer. The available bandwidth is a crucial information to the decision made by Admission Control for QoS support in wireless networks. Most of existing Admission Control schemes proposed for wireless Ad-Hoc networks neglect the fact that collision...
A Graphical SystemC-based Wireless Sensor Network environment is presented. It allows system-level simulations with graphical inputs and outputs to easily simulate such distributed systems. The IEEE 802.15.4 standard is modeled; it is then possible to easily simulate scenarios at high level, taking many hardware and software low level parameters into account. It also enables design space exploration...
Mobile ad-hoc networks (MANETS) are formed by a collection of mobile nodes that have the ability to form a communication network without the help of any fixed infrastructure. Because of the nature of these networks, routing protocols play a prominent role in their scalability and overall performance. Due to limited radio transmission range, multiple hops may be required in order to exchange data among...
Microscopic aspects of traffic codes for heterogeneous traffic flow are considered to be optimal for the performance of vehicular ad-hoc network. Within the scope of this concept, fluid dynamic model was applied for density estimation of heterogeneous traffic conditions. The effect of jamming density on velocity and density dynamics having influence of safety distance between the vehicles is accordingly...
The sparse and fluctuating bandwidth that characterize wireless links in ad-hoc networks present challenging conditions in our goal to ensure Quality of Service (QoS) in wireless connections and to maintain a satisfactory Quality of Experience (QoE) for the end user. In this environment, it is not only necessary to determine the current available bandwidth for a given link, but also to predict it...
In this paper, the issues in wireless resource management in multiuser multiple input multiple output (MIMO) systems are addressed. In particular, we investigate the problems in the design of user scheduling algorithms based on spatial division multiple access (SDMA). We review the existing scheduling algorithms optimized for single input single output (SISO) multiuser systems and point out their...
This paper provided a measurement campaign of simple antenna system mounted on a vehicle by utilising a Japanese geostationary test satellite called Engineering Test Satellite VIII (ETS-VIII). We developed an antenna system that was compact, light weight, and promising in low cost production. The antenna system was built by a 16-cm patch array antenna, which had simple satellite-tracking method that...
Dual-band planar antennas for Global Navigation Satellite System (GNSS) based remote sensing are presented. The antenna designed can cover both L1 and L2 bands, centred at 1.575 GHz and 1.227 GHz, respectively. They will be used onboard satellites remote sensing satellites as part of an instrument to measure ocean roughness by GNSS reflectometry, and the meteorology of the atmosphere by radio occultation...
In this paper, we present a Direction of Arrival estimation algorithm by combining Expectation Maximization (EM) and Matrix Pencil Method (MPM). It is possible that, when using a long uniform array, a few elements may fail, or the half-wavelength spacing between the elements may not be satisfied due to the spatial constraint. Under such situation, the array is known as sublattice array, which is a...
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