arXiv subjects

Nazar Ali

Publications and source records attributed to Nazar Ali.

7 recordsLinked to original sources

arXiv2018

Compact Low-Profile Wearable Antennas For Breast Cancer Detection

Many lives can be saved if tumors are detected in early stages, which can result in a bigger chance for recovery. Many patients find it irritating to get regular checkups due to the fact that the majority of the monitoring systems are complicated, not available everywhere and not mobile. Furthermore, for medical field applications, micro-strip antennas are efficient and have flexible properties that are utilized in imaging, diagnosis and treatment. It is known that breast cancer is the most common type of cancer in the world, and the earlier its been detected the better. In the early stages of breast cancer, getting rid of from the tumors is much easier and more guaranteed. Nowadays, the main method that is used in the hospitals for breast cancer detection is the Ultra-Wideband method (UWB). However, Many patients find it irritating to get regular check ups due to the fact that the majority of the monitoring systems are complicated and not mobile.

eess.SP↗

arXiv2018

Assessment of SFSDP Cooperative Localization Algorithm for WLAN Environment

Cooperative localization for indoor WiFi networks have received little attention thus far. Many cooperative location algorithms exist for Wireless Sensor Network Applications but their suitability for WiFi based networks has not been studied. In this paper the performance of the Sparse Finite Semi Definite Program (SFSDP) has been examined using real measurements data and under different indoor conditions. Effects of other network parameters such as varying number of anchors and blind nodes are also included.

eess.SP↗

arXiv2017

Error Rates Analysis of MIMO Space-Time Block Codes in Generalized Shadowed Fading Channels

This paper introduces a new and unified bit error rates performance analysis of space-time block codes (STBC) deployed in wireless systems with spatial diversity in generalized shadowed fading and noise scenarios. Specifically, we derive a simple and a very accurate approximate expressions for the average error rates of coherent modulation schemes in generalized $η-μ$ and $κ-μ$ shadowed fading channels with multiple input multiple output (MIMO) systems. The noise in the network is assumed to be modeled using the additive white generalized Gaussian noise (AWGGN), which encompasses the classical Laplacian and the Gaussian noise environments as special cases. The derived results obviate the need to re-derive the error rates for MIMO STBC systems under many multipath fading and noise conditions while avoiding any special functions with high computational complexity. Published results from the literature, as well as numerical evaluations, corroborate the accuracy of our derived generalized expressions.

cs.IT↗

arXiv2017

Exploring Symmetry in Wireless Propagation Channels

Wireless communications literature is very rich with empirical studies and measurement campaigns that study the nature of the wireless propagation channel. However, despite their undoubted usefulness, many of these studies have omitted a fundamental yet key feature of the physical signal propagation, that is, wireless propagation asymmetry. This feature does not agree with the electromagnetic reciprocity theorem, and the many research papers that adopt wireless channel symmetry, and hence rendering their modeling, unexpectedly, inaccurate. Besides, asymmetry is unquestionably an important characteristic of wireless channels, which needs to be accurately characterized for vehicular/mobile communications, 5G networks, and associated applications such as indoor/outdoor localization. This paper presents a modest and a preliminary study that reports potential causes of propagation asymmetry. Measurements conducted on Khalifa University campus in UAE show that wireless channels are symmetric in the absence of symmetry impairments. Therefore, care should be taken when considering some practical wireless propagation scenarios. Key conclusions and recommendation are summarized. We believe that this study will be inspiring for the academic community and will trigger further investigations within wireless propagation assumptions.

cs.IT↗

arXiv2017

Investigation of Wireless Channel Asymmetry in Indoor Environments

Asymmetry is unquestionably an important characteristic of the wireless propagation channel, which needs to be accurately modeled for wireless and mobile communications, 5G networks, and associated applications such as indoor/outdoor localization. This paper reports on the potential causes of propagation asymmetry. Practical channel measurements at Khalifa University premises proved that wireless channels are asymmetric in realistic scenarios. Some important conclusions and recommendation are also summarized.

cs.IT↗

arXiv2017

Moment Generating Functions of Generalized Wireless Fading Channels and Applications in Wireless Communication Theory

In this paper, new exact and approximate moment generating functions (MGF) expression for generalized fading models are derived. Specifically, we consider the $η-λ-μ$, $α-μ$, $α-η-μ$, $α-λ-μ$, $α-κ-μ$, and $α-λ-η-μ$ generalized fading distributions to derive approximate MGF expressions. The new expressions are very accurate and, in contrast to earlier results in the literature, avoid any complicated special functions, e.g. the Meijer-$G$ and Fox $H$-functions. As such, the new MGF expressions allow easier and more efficient analytical manipulations, which also apply for their special cases such as the Rayleigh, Rice, and Nakagami-m fading. As an illustrative application, the average bit error rates for each of the fading models are evaluated using the new derived MGF expressions. The accuracy of the analytical results by using the numerically computed results as a basis of comparison as well as published results from the literature.

cs.IT↗

arXiv2017

Linear and Circular Microphone Array for Remote Surveillance: Simulated Performance Analysis

Acoustic beamforming with a microphone array represents an adequate technology for remote acoustic surveillance, as the system has no mechanical parts and it has moderate size. However, in order to accomplish real implementation, several challenges need to be addressed, such as array geometry, microphone characteristics, and the digital beamforming algorithms. This paper presents a simulated analysis on the effect of the array geometry in the beamforming response. Two geometries are considered, namely, the linear and the circular geometry. The analysis is performed with computer simulations to mimic reality. The future steps comprise the construction of the physical microphone array, and the software implementation on a multichannel digital signal processing (DSP) system.

cs.SD↗