Interference Environment Between High Altitude Platform Networks (HAPN), Geostationary (GEO) Satellite and Wireless Terrestrial Systems

A new broadband telecommunication system has been recently proposed for provision of fixed, mobile and personal services adopting the use of high altitude platform stations placed in a fixed position in the stratospheric layer at heights from 15.5 to 30 km. The International Telecommunication Union (ITU) has allocated a pair of 300 MHz of spectrum in the V band for these services, which is already in use by geostationary satellite and wireless terrestrial systems as co-primary allocations. This paper addresses an in-depth co-channel interference analysis and proposes a C/I (carrier-to-interference) calculation model applicable to all the interference propagation paths as well as sharing criteria between HAPN, GEO satellite and wireless terrestrial systems extracted from simulations performed in urban, suburban and rural environments. By evaluating the interference density cumulative probability distribution functions, sufficient geographical separation distances between the ground stations are proposed which guarantee the harmonic co-existence between the three broadband systems. Maintaining the platform stable in the stratosphere is a key issue, and in this paper the effect of the three different stratospheric platform’s movement models (ITU, HELINET, HALO) appearing in the literature, on C/I levels is estimated.Vasilis F. Milas {received the Diploma in Electrical and Computer Engineering from the National Technical University of Athens, Greece, in 2000. From October 2000 until October 2001 he joined Space Engineering S.P.A in Italy (Rome) as a field practicing engineer where he was mainly involved into the design and realization of satellite telecommunication systems. Since November 2001 he is a member of the Mobile Radiocommunications Laboratory at the National Technical University of Athens working towards his Ph.D. degree with focus on high altitude platform systems and interference characterization on wireless communication systems.Philip Constantinou {received the Diploma in Physics from the National University of Athens in 1972, the Master of Applied Science in Electrical Engineering from the University of Ottawa, Ontario, Canada in 1976 and the Ph.D. degree in Electrical Engineering in 1983 from Carleton University, Ottawa, Ontario, Canada. From 1976 to 1979 was with Telesat Canada. In 1980 he joined the Ministry of Communications in Ottawa, Canada. From 1984 to 1989 he was with the National Research Centre Demokritos in Athens, Greece were he was involved on several research projects in the area of Mobile Communications. In 1989 he joined NTUA where he is currently Professor. His current research interests include Mobile Satellite Communications and Interference Problems on Digital Communications Systems.     

LTE—Advanced：强有力的4G候选标准

文章详细介绍了正处于标准紧张制定过程中的LTE-Advanced系统,描述了该系统产生的背景、目前的进展、演进目标以及系统中的新技术特征等方面的问题,最后简要介绍了其他4G候选技术以及中国在4G标准中的地位。     

一种数字延时器的设计原理

电视延时设备广泛应用于电视直播任务中，从延时器的各个功能模块入手分析探讨了延时器的设计原理，为最终设计的产品化提供技术理论支持。     

光纤、光缆建议和标准应用指南

在ITU—T最近编制的40号补充文件的基础上，试图将我国有关的国标和行标的内容也增加进去，对有关光纤／光缆的这些标准的应用加以引导，供大家在实际工作中参考。     

智能网标准化研究的进展概况

目前，国际上许多标准化组织都在进行智能网标准的研究，其中对我国的智能网标准化工厂产生影响的国际标准化组织主要有国际电信联盟（ＩＴＵ）和欧洲电信标准研究所（ＥＴＳＩ）。本文分别介绍ＩＴＵ，ＥＴＳＩ及我国的智能网标准化研究的进展情况。     

载干比在地球静止卫星轨位协调中的应用

在目前的邻星协调方面,国际电联(ITU)推荐2个同频段、共服务区的地球静止卫星之间的最小轨位间隔为3°,结合工程实际,按照国际电联(ITU)推荐的分析方法,结合卫星的具体配置,将载干比用于两颗临近轨位的地球静止卫星的干扰分析,分析结果表明:这两颗卫星的最小轨位间隔可以确保优于3°,从而提高了宝贵的空间轨位资源利用率.     

桌面视频会议系统技术标准简介

桌面视频会议系统是多媒体技术，数据压缩技术和网络通讯技术的结合。为了促进该技术的发展，有关国际组织制定了一系列的标准。本文介绍了ＩＴＵ制定的Ｔ．１２０，Ｈ．３２０。Ｈ．３２３和Ｈ．３２４标准。并对Ｔ．１２０、Ｈ．３２０标准进行了较为详细的介绍。     

B3G研究与标准化进展

在市场业务需求与无线新技术发展的联合驱动下,B3G将要从研究领域的热点进入实际的产业化应用过程.本文以ITU对于IMT-Advanced的工作计划为线索,结合IEEE、3GPP/3GPP2等国际标准化组织的技术发展情况,介绍关于B3G的研究与标准化进展.     

基于改进的Goertzel算法的双音多频检测器的设计

利用国际联盟（ITU）关于双音多频（DTMF）信号的建议和双音多频检测算法的理论背景,提供了双音多频发生器和检测器的具体算法和Matlab实现细节,其中的改进的基于音调检测Goertzel算法,能够满足ITU全部建议要求．     

Effect of burnup on the neutronic parameters of ITU TRIGA Mark II research reactor

This study aims to estimate burnup of the fuel elements for the Istanbul Technical University TRIGA Mark II Research and Training Reactor using a Monte Carlo-based burnup-depletion code. Effect of burnup on the core neutronic parameters, effective core multiplication factor, fast/epithermal/thermal neutron fluxes, and core-average neutron spectrum, and incoming neutron spectrum of the piercing beam port (PBP), is investigated at the Beginning of Life (BOL) and End of Life (EOL). Operational data peculiar to a selected operation sequence, which contains positions of CRs, power level of the reactor, material temperatures and latest core map, are used to determine the current fuel burnup of fuel elements at the time under consideration. A specific operation sequence is selected for the analysis. Furthermore, all control rods are considered fully withdrawn to assess the excess reactivity. Results are obtained using MONTEBURNS2 with ENDFB/V-II.1 neutron/photon library for a full power of 250 kW. Neutron cross-section libraries at the full-power operating temperatures are generated using NJOY. From the results, the calculated burnup values of the core at the sequence considered and EOL are found to be 420 MWh and 560 MWh, respectively. Remaining excess reactivity is calculated to be less than 0.3 $. It is observed that core average thermal neutron flux reduces by 1 % while the fast and epithermal neutron fluxes remain almost unchanged.