research centers


Search results: Found 2

Listing 1 - 2 of 2
Sort by

Article
HIGH ALTITUDE PLATFORM STATIONS IN DESIGN WIRELESS COMMUNICATION SYSTEM FOREAR COVER THE SPECIFIC A

Author: Yousif Mohsin Hasan
Journal: Al-Qadisiyah Journal for Engineering Sciences مجلة القادسية للعلوم الهندسية ISSN: 19984456 Year: 2017 Volume: 10 Issue: 4 Pages: 600-611
Publisher: Al-Qadisiyah University جامعة القادسية

Loading...
Loading...
Abstract

This paper explains how to design a wireless communication system via high altitude platform stations HAPS to cover the specific area (Using Diwaniyah city area as a model). High altitude platform station HAPS is unmanned airplane provides the wireless communication service to the wider area. It is designed to work at high altitude between (17-22 Km) and coverage area 400 Km. This study illustrated for calculating the co-channel interference between HAPS ground station with a terrestrial station and satellite station. Free space losses for a HAPS ground station has been applied to meet the geographic of Diwaniyah city. In addition, explaining the relationship between elevation angles with the radius of the coverage area. Interference mitigation techniques have been given, such as improving the antenna radiation pattern, then it proposed the elevation angle for the HAPS's ground stations to reduce an interference between HAPS network with Fixed Service (FS) and fixed satellite service (FSS). Finally, this study explains the relationship between elevation angles with the radius of the coverage area. For more reliability, the Scenario for covers the city of Diwaniya. Two ground stations have been proposed to connect with high-altitude platform station.


Article
Improve the Performance of Transferring WiMAX OFDM Signals Over Laser Communication Links Based on Optimum Gain of Laser Transmitter

Author: Awwab Qasim Jumaah Althahab
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2015 Volume: 23 Issue: 3 Pages: 616-626
Publisher: Babylon University جامعة بابل

Loading...
Loading...
Abstract

A high-altitude platform (HAPs) that can provide high data-rate wireless services is one of the most modern technologies where a WiMAX (IEEE 802.16) base station carried and implemented over its board. HAPs can be considered as a supporting network that wireless broadband services across far distances on the Earth are transferred. The network providing a WiMAX coverage on grounding subscribers includes users on the ground, several HAPs and a satellite. An analog radio frequency (RF) over laser communication (LC) is an optical link, and it is considered as a transmitter link between the HAPs and the satellite in which the WiMAX base station is located. A laser transmitter and an optical receiver are needed to comprise a LC system. Both of them must be strictly aligned to achieve a line of sight link. On the other hand, the transmitter-receiver alignment is probably being defied due to electronic noise and mechanical vibration in the control system causing laser path loss and pointing errors. In other words, the received signal is fading due to the outcome of pointing errors, thus, link performance defects. The goal of this paper is to improve the performance of wireless mobile communication network through minimizing the outage probability of the WiMAX link. This can be done by finding the optimum value of laser transmitter gain, which is finally derived in this paper as a function of , the radial pointing error angle. Lastly, results and performance of outage probability are evaluated by using computer simulation in MATLAB 11.

المنصة عالية الارتفاع (HAPs) توفر خدمات لاسلكية ذات معدل معلومات عاليه هي واحدة من أكثر التقنيات الحديثة حيث محطة الواي ماكس WiMAX (IEEE 802.16) تحمل وتنفذ على سطحها. المنصات عالية الارتفاع ممكن اعتبارها كشبكة دعم من خلالها يمكن نقل خدمة الاتصالات ذات النطاق العريض عبر مسافات بعيدة عن الأرض. الشبكة التي تجهز تغطية كاملة للمستخدمين لإشارة WiMAX وتتألف من القمر الصناعي, عدة منصات عالية الارتفاع ومشتركين على الأرض. إشارة الترددات الراديوية التماثلية عبر اتصالات الليزر هو وصلة بصرية ويعتبر وصلة نقل بين المنصات عالية الارتفاع وبين القمر الصناعي حيث وجود محطة الواي ماكس WiMAX. نظام الاتصالات الليزرية يتألف من ناقل ومستلم ضوئي. يجب ان تكون المحاذاة بينهما ذات دقة عالية لتحقيق خط الارتباط البصري. من ناحية أخرى، محاذاة الناقل والمستلم للإشارة ربما تواجه تحدى بسبب الضوضاء الإلكترونية والاهتزازات الميكانيكية في نظام السيطرة مما يسبب في فقدان مسار الليزر وتشكيل أخطاء. بعبارة أخرى, الإشارة المستلمة سوف تتلاشى بسبب نتيجة تشكيل الأخطاء ولهذا يحصل خلل أو ضعف في الاتصال. الهدف من هذا العمل هو تحسين أداء شبكة الاتصالات اللاسلكية من خلال تقليل احتمالية القطع الاتصال لإشارة WiMAX. ويمكن القيام بذلك من خلال إيجاد القيمة المثلى لربح مرسل الليزر، والتي أخيرا اشتقت في هذا العمل كدالة ( ), زاوية الخطأ الملفت النصف قطري. في الختام النتائج وأداء احتمالية القطع نفذت باستخدام الماتلاب 2011.

Listing 1 - 2 of 2
Sort by
Narrow your search

Resource type

article (2)


Language

English (2)


Year
From To Submit

2017 (1)

2015 (1)