Fayez W. Zaki

Multi-level stable and energy-efficient clustering protocol in heterogeneous wireless sensor networks

Classical clustering protocols in wireless sensor networks (WSNs) assume that all nodes are equipped with the same amount of energy. As a result, they cannot take full advantage of the presence of node heterogeneity. In this study, a stable and energy-efficient clustering (SEEC) protocol for heterogeneous WSNs is proposed. In addition, the extension to multi-level of SEEC is presented. It depends on the network structure that is divided into clusters. Each cluster has a powerful advanced node and some normal nodes deployed randomly in this cluster. In the multi-level architectures, more powerful supper nodes are assigned to cover distant sensing areas. Each type of nodes has its role in the sensing, aggregation or transmission to the base station. At each level of heterogeneity, the optimum number of powerful nodes that achieves the minimum energy consumption of the network is obtained. The proposed protocol is a heterogeneous awareness to prolong the stability period, which is crucial for many applications. The performance of the proposed protocol is compared by existing homogeneous and heterogeneous protocols. Simulation results show that the proposed protocol provides a longer stability period, more energy efficiency and higher average throughput than the existing protocols.

Energy efficiency of virtual multi-input, multi-output based on sensor selection in wireless sensor networks

In this paper, a weighted node selection technique in wireless sensor networks is proposed. It is an energy-efficient cooperative technique where a selected number of sensors at the transmitting end are connected with a selected number of sensors at the receiving end to form a virtual multi-input multi-output. The proposed technique is based on a weighted selection function that combines geographical location, inter-sensor distance in a cluster, channel estimate energy, power circuit, channel loss, mobility factor, and residual energy of each sensor. The weight of each of these parameters in the selection function depends on the degree that this parameter affects the energy consumption. Then, the cluster head selects the sensors with better selection parameters that reduce the overall energy consumption. The numerical results show that the proposed weighted node selection technique achieves a significant improvement in the energy consumption, delay, and network lifetime than the conventional techniques with and without the selected number of sensors. Its improvement reaches 15% in the energy consumption that leads to an increase in the network lifetime by four times the network lifetime of other techniques. Copyright

DCT and DWT feature extraction and ANN classification based technique for non-destructive testing of materials

Eddy current (EC) nondestructive testing (NDT) based on probe impedance and magnetic flux density in the defect regions is considered in this work. For this a numerical model is introduced for the development of the EC-NDT system using 3D finite element analysis. This model is used to simulate the material defects and prepares the data required for computer simulation of the EC-NDT system. The image data for three types of cracks in two types of materials are processed by discrete cosine (DCT) and discrete wavelet (DWT) transforms for feature extraction. Depending on the extracted features, the defects are classified using artificial neural network. A series of computer simulation experiments are carried out to assess the performance. 100% correct crack identification is achieved.

C2. Uplink performance of MIMO multi-hop LTE-A based on Link Adaptation

Multi-hop cellular network with relay components is a major concern in research studies around the world. This is due to the fact that it can aid the cell to achieve coverage extension, throughput and capacity enhancement. LTE-Advanced is the candidate from (3GPP) to meet (IMT)-Advanced requirements. This paper discuss the impact of RS placement on the LTE-Advanced Uplink performance using MIMO and AMC schemes, taking into consideration the effect of different arrival rates from random positioning UEs in the cell. Simulation results show the RS coverage area, total uplink cell throughput, and mean file transfer times for different RS positions with SISO-AMC (Adaptive Modulation and Coding) scheme and compare results with 2×2MIMO-AMC scheme.

Processing and classification of palmprint images

Palmprint segmentation, which involves extracting a suitable part of a palmprint for feature extraction and matching, provides the basis for palmprint identification. Segmentation aims at automatically and precisely extracting the central part of a palmprint for feature extraction. In this paper, a square-based segmentation method is introduced. The main idea is to first define key points on a palmprint. An orthogonal coordinate system is then established by using the three points. During segmentation, a square with fixed size is extracted from a predefined position under the coordinate system. The basic rule in determining the size and position of the square is to ensure that the part of the extracted image is available in all palmprints. To perform palmprint identification, the PCA is applied to the segmented palms for dimensionality reduction. Wavelet transform features were fused with PCA to improve identification results. The hamming distance was used for classification purpose. Results have shown that fusing PCA and wavelet features had led to an identification ratio of 99.4% which is better than previously investigated techniques.

Speech compression using wavelet transform

A great deal of mathematical and engineering analysis depends on methods for representing a complex phenomenon in terms of elementary, well-understood phenomena. Recently wavelet theory has provided a new method for decomposing a function or signal. Wavelet transforms of real signals tend to create low-value coefficients at the finer scale. This property makes it possible to devise compression schemes that quantise the fine-scale coefficients more severely than coefficients at other scales. In this paper, two schemes for speech compression based on wavelet transform are introduced. In the first one, short time segments of speech samples are wavelet transformed and quantised using different types of quantisers. In the second scheme, a linear prediction is carried out using the autocorrelation method and tapped delay line transversal filter, then the prediction residual is wavelet transformed, quantised, and transmitted. A good quality speech reproduction is obtained at compression ratios of 50%-90.36%. The system may find its applications in cellular and satellite communications.

Studies on relay modes and system capacity in WiMAX IEEE 802.16m multi-hop relay networks

Relay technologies have been actively studied and considered in the standardization process of next-generation mobile broadband communication systems such as 3GPP LTE-Advanced, IEEE 802.16j, and IEEE 802.16m. This paper introduces and compares different relay schemes as applied to IEEE 802.16m WiMAX. Simulation results show that relay technologies can effectively improve service coverage and system throughput. Three relay transmission schemes are then summarized and evaluated in terms of transmission efficiency under different radio channel conditions. This paper focuses on the performance analysis of IEEE 802.16m multi-hop relay systems in downlink traffic, MATLAB program was used. Through these tools, a performance analysis of these systems was carried out under different deployment scenarios. Within the different scenarios several aspects of the system design were considered. These include the methods to determine the type of relay mode to maximize the gain that can be provided through the deployment of relays.

Comparative Study of Power Saving and Delay in LTE DRX, Directional-DRX and Hybrid-Directional DRX

With integration of advanced long term evolution networks (LTE networks) in mobile technology, 5G networks are introduced due to broadband spectrum extension which requires higher power consumption. Discontinuous reception (DRX) sleep mode mechanism is provided to accommodate lower power consumption of user equipment terminals (UEs). For mmWave directional communication air interface in LTE between UE and LTE eNB, UE performs beam searching and alignment with LTE eNB (4G base station) after every short/long DRX cycle during ON duration. Dual connectivity of UE to both LTE eNB and NR NodeB (5G New RAN base station) is a hybrid-directional system. This allows us to propose a sleep mode mechanism which is called hybrid directional-DRX (HD-DRX). In HD-DRX, UE performs beam searching and alignment with NR NodeB during ON duration only if data packet intimation. A semi-Markov chain process is introduced to describe UE state transition. Depending on this chain, power saving factor and average delay are calculated. HD-DRX power saving as compared to LTE DRX and Directional-DRX (D-DRX) is conducted. Due to different beam searching procedure, another comparison of average delay is assigned between D-DRX and HD-DRX. Data traffic model parameters are considered and numerical analysis is validated using MATLAB program simulations.

Performance Evaluation of Sleep Mode on Power Saving in WiMAX IEEE 802.16m and LTE DRX

Power saving represents a vital role in mobile communications networks such as IEEE 802.16m and LTE. Modern user equipment (UEs) require high data rates and low power consumption. It is found that arranging sleep mode mechanisms ensures UE battery longer lifetime. In this paper, different sleep mode mechanisms are investigated for both IEEE 802.16m and LTE networks. The analyses are based on Markov and Semi-Markov chains. It is focused on the determination of UE transition state. Web traffic model parameters were considered in MATLAB simulation and a comparison assessment was conducted between WiMAX IEEE 802.16m and LTE DRX. It was found that LTE DRX sleep mode provides more power saving than WiMAX IEEE 802.16m sleep mode. The study is now implemented for 5G networks with encouraging results.

Joint energy and spectral efficient power allocation for long term evolution-advanced

Abstract In wireless communication systems, energy efficiency (EE) and spectral efficiency (SE) tradeoff is a challenging issue as they are inversely proportional to each other. Most previous work has provided the communication between two points that may lead to the inefficient use of network resources. It is crucial to study optimal power allocation (PA) including relay nodes in order to improve power saving and data rate. This paper proposes a PA optimization method for multi-user, based on EE and SE in Long Term Evolution-Advanced (LTE-A). The optimization problem is formulated as multi-objective optimization (MOO), considering both downlink and uplink transmissions. The mathematical expression of optimal power for EE and SE (OPES) is derived for Transparent and Non-Transparent modes with amplify-and-forward (AF) relay. Numerical results confirm the effectiveness of the proposed OPES formula compared to previously used techniques.