Hadia M. El-Hennawy

WSN Application Traffic Characterization for Integration within the Internet of Things

The Internet of Things (IoT) aims to connect the growing number of sensing and monitoring devices to humans or other devices with the goal of exchanging data or controlling these devices. IoT can be considered as the set of technologies that allow small devices e.g. sensors, which constitute wireless sensor networks (WSNs) that perform specific tasks, to communicate over the Internet Protocol (IP). Cellular networks, especially LTE, are an attractive technology to provide Internet connectivity to these potentially remote devices. In order to allow the cellular networks to connect these devices reliably to the Internet, the traffic of WSNs should be studied to understand their unique requirements on the cellular infrastructure. This is because the existing cellular networks have been traditionally designed mainly to support human to human communication in which case the traffic is completely different than that of WSNs. This paper aims to shed some light on the possible integration challenges that are imposed by the integration of WSNs and LTE which manifest themselves in the difference in traffic characteristics. We perform some experiments to explore the behavior of specific WSN application traffic. We then discuss the possible adaptation that is required for the successfully integration of the two technologies.

Space-Charge Plane-Wave Interaction at Semiconductor Substrate Boundary

A theoretical investigation of space-charge plane-wave interaction at dielectric-semiconductor interfaces is presented. A full-wave and charge transport formulation is applied to the analysis of the fundamental mode of propagation in a semiconductor substrate backed with a ground plane. Closed-form expressions for the field components, charge carrier density, and current density are obtained. The reflection coefficients for both H- and E-polarized incident waves were then derived from the field solutions. The interaction between the fields and charge carriers causes a charge accumulation at the semiconductor surface in the case of H-polarization. The effects of the charge accumulation on the reflection coefficient are accounted for. Results indicate that the space charge exerts a weak effect on the reflection coefficient and a strong screening effect on the normal component of the electric field. The tangential component, however, is mainly governed by energy dissipation effect resulting from the conduction current.

UWB KSA Sign Shape Slot Microstrip Antenna Array Mutual Coupling Reduction for Official Applications

A novel single element KSA (Kingdom of Saudi Arabia) sign shape, and two element array (Ultra Wide Band) KSA sign shape slot microstrip antennas are presented. A novel KSA sign shape EBG cells are applied to reduce the mutual coupling between array elements with the same shape. The results show that a reduction in mutual coupling of 8 dB is achieved at first band (2.1 - 2.99) GHz and 33 dB at second band (5 - 9.43) GHz. The microstrip array was studied by CST simulator and fabricated by proto laser machine with precision 25µm. The antenna can be used in the military or RFID applications. Index Terms—Microstrip patch antenna, mutual coupling, EBG, KSA sign shape. compactness in EBG structures, different shapes with significant gaps are designed (5). The practical applications of EBG structures have difficulties in accommodating their physical sizes. In this paper, the proposed EBG structure is a KSA sign shape which has more gaps and compactness. The technique used in this paper to reduce mutual coupling loss, by increasing the number of EBG cells and by varying the gap distance between cells. The reduction in mutual coupling by means of periodic structure becomes particularly efficient when grating lobes must be avoided (6). Array antennas are mostly large in size also to improve the performance of the arrays EBG cells are to be placed in between the patch antenna which makes the size much larger. So as to reduce the size of the antenna the proposed method is designing small cells of KSA sign shape for placing EBG cells closer to the patch antenna placed together in the same layer. Another, major drawback of patch antennas array is narrow bandwidth. A possible way to increase the bandwidth is to either increase the height of the dielectric or decrease the dielectric constant. In this paper the first two drawbacks and its approaches are analyzed and the simulated and measured results are also obtained. This configuration is chosen because the KSA sign shape is the official page for any military application. So, this antenna may be used in soldier belts, any commodity for the military application, etc. It should be noted that its main application depends on the range of frequency. According to the chosen ranges of the operating frequency it can be used in RFID (7) or in communication systems.

New configuration for multiband ultra compact gap resonator based D-CRLH

A new compact multiband resonator based on one modified cell of dual-composite right/left-handed microstrip structure is presented in this paper. This introduced topology proposes triple band for 7.4 GHz, 9.2 GHz, and 13 GHz with insertion loss 2.3 dB, 0.6 dB, and 0.55 dB, respectively. Moreover, the return losses are equal 13 dB, 43 dB, and 10 dB, respectively. The paper elaborates the equivalent circuit model, analytical study and 3D full-wave simulation. Furthermore, the design realizes compactness size (13.2 × 5.9 mm2). The quality factor demonstrates selectivity equals 35, 8.18, and 48.1 at the four bands, respectively.

B3. Dual polarized channel strip-map SAR system for land imaging

A proposed dual polarized strip-map synthetic Aperture Radar (SAR) simulation based on ray tracing method has been introduced for land imaging. A high resolution-wide swath SAR image for a random rough surface can be obtained by this simulation. The random rough surface is characterized by the statistical properties of the surface geometry described by the root mean square height hrms and the correlation length lc. The influence of the roughness and the dielectric properties of the surface on the backscattered signals received by the SAR antenna are discussed at c-band (5 GHz). The operating wavelength 6 cm is shorter than the surface variation. This enables the use of the geometrical theory of diffraction to account for the backscatter form the rough surface. The proposed SAR system will be used to demonstrate a high resolution image of the Suez Canal region.

Cooperative wideband spectrum sensing over Rician and Nakagami fading channels

Spectrum sensing technique is the most crucial factor that determines the performance of Cognitive Radio (CR) systems. Wideband spectrum sensing using Nyquist and sub Nyquist sampling rates proved to have better performance than other types of spectrum sensing. Multi-rate spectrum sensing technique have advantage over other wideband spectrum sensing technique regarding the probability of detection, probability of false alarm and the implementation complexities. In this paper, analysis of the effect of two different fading channels namely; Rician fading channels (with different values of Rice factor K) and Nakagami-m channel (with different values of Nakagami factor m) on the performance of multi-rate spectrum sensing systems are presented. Results are consistent with previous published studies on the effect of other types of fading namely; Rayleigh and log-normal fading channels.

Connection Admission Control Reward Optimization for Different Priority Classes in Homogeneous Wireless Network

Nowadays, Connection Admission Control (CAC) reward optimization for a service with different priority classes in a homogeneous wireless network has become one of the most important issues. In this paper, a novel expansion for the Guard Channel Based Incremental and Dynamic Optimization algorithm is presented. GUIDO will be used to analyze a reward scheme that correlates service demand with weights on pricing, after which optimal weights are deduced for maximum system reward, taking into consideration QoS for the different priority classes. An analytical model is presented based upon Lagrangian Optimization criterion and is used to verify the optimal weights. The paper thus, suggests the optimal weights on pricing for maximum system reward and offers an analytical derivation for them.

Performance Assessment for the Selection Transmit Diversity in Adaptive Polarized MIMO Pre-RAKE System

This paper evaluates the performance of the Selection Transmit Diversity (STD) technique in adaptive Polarized Multiple-Input Multiple-Output (MIMO) Pre-RAKE system. The proposed system will be examined in Frequency Division Duplex (FDD) mode. For the same spatial dimensions, the proposed system will be compared with the Pre/Post RAKE systems and the single-polarization Pre-RAKE STD systems. As will be shown, our system can achieve a much better performance in addition to simplify the receivers implementation. Also, the system performance will be investigated in case of excluding the cross-pol Pre-RAKEs in the base station. The paper discusses the effect of the polarization diversity characteristics as well as the impact of the imbalance in the co-polarized power intensities on the BER performance. For slowly-varying channels, an assessment for the system performance will be investigated under different Feedback Information (FBI) rates. In addition, a performance comparison for vehicular and pedestrian environments will be presented.

Electromagnetic simulation for land imaging using fully polarimetric SAR system

In this paper, a simulation concept is presented for creating full polarimetric synthetic aperture radar (SAR) images based on ray tracing and geometrical theory of diffraction GTD. The RRS model is illuminated by a virtual SAR sensor whose signal is approximated by rays sent through the SAR aperture. The path of each ray is traced starting from the SAR aperture until the ray reached back the aperture; taking into account the direct and multiscatter paths. The cross-polarization is studied as a useful source of data that can be used with co-polarization data to retrieve the surface roughness parameters (root-mean-squared height hrms and the correlation length lc) and the dielectric properties. The effectiveness of the roughness parameters and the electric properties of the surface on the scattered signals are studied using high frequency approximations (6 cm wavelength), which is much shorter than the surface variation. This empowers the utilization of the geometrical theory of diffraction to represent the backscatter signals form the rough surface. The proposed fully polarimetric SAR system will be used to demonstrate a four polarized images of the Suez Canal region.

Wide-band sensing and optimization for cognitive radio networks using multi-rate sub-Nyquist spectrum sensing (MS3)

Recently in cooperative spectrum sensing, there are many researches on designing strategies for the optimization of the length of the sensing time (as a part of the total frame length) while fulfilling the objective of achieving certain level of protection of primary users. The performance of cooperative spectrum sensing scheme is greatly affected by the length of the sensing time selected or calculated by the fusion scheme. Different scenarios and types of energy detectors were studied. In this paper a sensing time - throughput trade off scenario is designed using generalized energy detector (GED) combined with the use of the wideband multi-rate sub-Nyquist spectrum sensing technique (MS3). The objective is to calculate and determine an optimum value of the sensing time that maximizes the secondary user throughput while achieving maximum protection of the primary user. The strategy for finding the optimum value of the sensing time is the same followed by other researchers, which derived and calculated the optimum sensing time and throughput using other types of energy detectors. The calculations and simulation results showed that MS3 technique proved to have better performance (smaller sensing time while achieving higher value of probability of detection Pd).