WRC-97第5委员会工作情况

一、增加非对地静止轨道卫星移动和卫星固定业务可用频段根据大会通过的决定，在3GHz以下，由于大多数国家的反对，末为卫星移动和卫星固定业务划分新的频段，这对保护我国现有的地面和空间业务（如1675-1710MHz的气象辅助业务）是有利的。在一些频段，把卫星陆地、水上、航空移动业务合并为通用的卫星移动业务。对有些频段，通过了一些决议，要求继续研究并用问题，在以后的大会上再进行讨论，有的已列入了下次大会议程。由于空间技术的发展和对全球移动个人通信、宽带信息传输需求的增长，继上次大会以后，在本次大会上，发达国家要求为…     

卫星移动业务C频段的干扰研究

分析了卫星移动业务与地面固定业务共用C频段时,对该频段地面固定业务的干扰情况。以世界无线电通信大会议题提出的卫星移动业务候选频段为背景,从理论上分析了卫星移动系统上行链路与下行链路对固定业务的干扰情况。利用国际电联相关建议搭建了干扰分析模型,并进行了仿真分析。通过分析,在假设的场景下,卫星移动业务的上行链路会对地面固定业务产生干扰,而上行链路不会产生干扰。     

S频段RDSS业务全球扩展分析

随着全球卫星导航系统(GNSS)的发展,现有的卫星无线电导航频率划分已无法满足日益增长的需求.根据ITU规则,S频段2 483.5～2 500 MHz频率范围在部分区域和部分国家为卫星无线电测定服务(RDSS)业务的首要分配,且该频率范围与地面移动通信服务2.5 GHz以上的频率范围接近,易于实现导航系统与移动通信系统实现硬件复用,使得该频段受到欧盟"伽利略"系统的重视,并提出了RDSS业务全球扩展的议题.在简要介绍S频段RDSS业务全球扩展背景的基础上,分析了S频段RDSS业务全球扩展的可行性,并针对我国S频段RDSS业务的使用情况和卫星导航系统频率资源占有情况,分析了我国开展S频段RDSS业务全球扩展研究的必要性,基于频率和轨位申报的需求,提出了需要研究的内容.     

6G Hz频段IMT系统对卫星固定业务干扰分析

6 GHz作为移动宽带发展频谱使用有利于全球5G产业持续健康发展,为满足6 GHz频段国际移动通信(IMT)系统的使用需求,需要开展6 GHz频段下IMT与同频卫星固定(地对空)业务频谱共存研究,以保护该频段的卫星固定(地对空)业务的正常工作。首先分析IMT系统对卫星固定(地对空)业务的干扰场景,然后采用蒙特卡洛仿真方法计算IMT系统对卫星的集总干扰,最后分析干扰情况。结果表明,在智能制造室内场景和室外场景两种情况下,对于长期保护标准和短期保护标准,均无干扰,将6 GHz频段用于IMT系统能够与卫星固定(地对空)业务共存。     

各国在2.6GHz频段应用的发展动态与分析

近几年来由于移动通信业务的飞速发展,2.6 GHz(2500～2690 MHz)频段引起了各国的极大关注.2.6 GHz频段靠近无线局域网(2.45 GHz)IMS频段,而且被指定为第三代移动通信(IMT2000)的频段.在这个频段上能够开展多项固定、移动、卫星广播等业务,且属于Ⅰ、Ⅱ、Ⅲ区共用,因此包括WiMax、802.20、B3G、卫星技术在内比较多的系统都在关注这段频段.目前,欧州、美国、日韩等国家都积极在这个频段上进行频谱规划和开展业务,尤其是今年初日韩推出的卫星数字多媒体广播业务(DMB),其技术应用和商业化程度都获得巨大的成功.我国目前也在积极准备利用2.6 GHz频段开展业务,并一直都在对2.6 GHz频段的频谱特性进行研究.今年7月,中国通信广播卫星公司已向国际电联提出申请使用该频段开展卫星广播业务,但是考虑到该频段的频率划分是移动、卫星广播及无线电定位等业务的共用频段,因此必须统筹考虑卫星协调和2.6 GHz频段的中长期规划等问题.     

我国风云气象卫星频谱使用权益得到有效保护

在促进新技术、新业务发展的同时,保护已有的无线电业务正常运行,是2019年世界无线电通信大会(WRC-19)一大重点任务。面对越来越多的小卫星测控系统使用401MHz^403 MHz和399.9MHz^400.05MHz频段频谱资源,WRC-19大会设立了1.2议题,审议确定这两个频段内已有的卫星移动业务(MSS)、卫星气象业务(MetSat)和卫星地球探测业务(EESS)中操作的地球站的带内功率限值,从而保护上述无线电业务的频谱使用权益。     

国际无线频率分配

为了减少无线电之间的相互干扰,国际电信联盟组织(WARC)在世界无线电管理会议上对不同频段的利用作了统一的安排.主要是将1～3GHz频率分配给移动无线电通信和移动无线卫星通信,将20GHz频率分配给新的卫星通信.关于频率分配的一致点有:1.广播卫星业务(声音)1.5GHz邻近频段(用于高质量卫星传送给移动接收机——如汽车等,每个国家均可利用.2.6GHz邻近频段分配给日本及附近国家(其他用途使用1.5GHz邻近的频率),而2.3GHz频段分配给美国和印度.     

超短波固定监测站接收机互调引发的困惑

近日,某单位在利用福州某超短波固定监测站开展频率普查工作时,发现144MHz～164MHz频段出现了多个调频广播电台信号。经查《中华人民共和国无线电频率划分规定（2010）》频率划分表,该频段对应的业务种类主要为固定、移动、无线电定位、卫星无线电导航等,并无广播业务信号。     

中美两国静止轨道卫星分类概述

本文对截至2019年6月的全球静止轨道卫星进行了统计,随后以业务为划分,重点介绍中美两国不同业务的静轨卫星,分析各系列卫星的数量、轨位、频段、业务功能等特征,最后对比分析两国静轨卫星发展现状,从中可窥见中国在高频段使用、卫星业务应用等方面同美国仍有显著差距。     

卫星固定业务规划频段新增动中通应用

<正>2023年世界无线电通信大会（WRC-23）决定批准一项新的决议草案,允许动中通按照所制定的规则程序和技术限制条件在12.75-13.25GHz规划频段内使用,使得该频段成为目前可用于动中通的标准Ku频段的有效补充。动中通即采用卫星固定业务频段在移动中通信的地球站。它可以安装在机动车、铁路机车（含动车组列车）、船舶、航空器等移动平台上,     

3 300~3 400 MHz频段无线电定位与LTE室内 覆盖系统同频共存分析

2015年世界无线电大会（WRC-15）的1.1议题（AI 1.1）正在开展关于新增频谱用于未来移动通信的相关研究。3 300~3 400 MHz频段具有较宽带宽,此频段适于移动宽带系统在密集城区提供高速数据传输业务,满足移动宽带系统对于频谱容量的需求。我国在这一频段目前主要存在无线电定位业务。本文分析了如果在3 300~3 400 MHz频段引入IMT室内系统,保护已有无线电定位业务所需的隔离要求。     

超高频RFID系统与其他无线网络的电磁兼容性研究

无线射频识别（RFID）技术与互联网、移动通信网络等技术结合应用,可以实现全球范围内物品跟踪与信息共享。然而,RFID作为无线通信系统,其发射的射频信号可能对其它无线网络造成干扰,降低系统性能,影响系统正常工作。中国已经发布了840～845MHz和920～925MHz频段RFID的试用标准,其中920～925MHz的RFID应用和点对点立体声广播处在一个同一个频段,与无中心对讲机和GSM网络处在相邻频段,RFID系统与这些系统之间的电磁兼容性就成为系统能否稳定实现的最主要因素。     

The future of high frequency broadcasting

Since the end of World War II, the number of daily frequency hours used by high-frequency (HF) broadcasting (also known as shortwave and band 7, 3-30 MHz) has tripled. Approximately 35000 daily frequency hours are carried in an HF spectrum that can barely accommodate half that amount. As a consequence, congestion is severe, and interference levels intolerably high. Attempts to remedy this situation by planning the high-frequency bands date back to 1947, but, thus far, they have not been successful. International planning conferences in 1984 and 1987 have shown a possibility for agreement; another conference is tentatively scheduled for 1992. Some broadcasters have attempted to solve their congestion problems by moving out-of-band, sometimes expanding their services int bands allocated to other services, such as amateur radio, fixed, aeronautical, and mobile. It is feared this trend will continue. The attempts that have been made to plan the HF bands in an effort to alleviate congestion are described and the outlook for the remainder of the 20th century is discussed     

Broadband dual frequency sleeve monopole antenna for DTV/GSM applications

A broadband dual frequency sleeve monopole antenna for application in digital television (DTV) systems and global system for mobile communications (GSM) is presented. A parasitic inverted L-shaped strip and dual planar sleeve structure are introduced in the back ground plane for expanding the frequency band. The simulated and measured results show that the impedance bandwidth covers the DTV (470? 862 MHz) band and GSM (824?960 and 1710?2170 MHz) band with VSWR less than 2.5. An omnidirectional radiation property is also shown.     

Summary of conclusions of the 1992 World Administrative RadioConference

The major decisions made at the conference are briefly described. Additional frequency bands for shortwave (HF) radio broadcasting were agreed upon. Frequency allocations were made to support a number of US proposals, to provide advanced mobile radio services using low Earth orbit satellites. Allocations for land based mobile services adopted at WARC '92, in the range 1700 to 2600 MHz, are meant to foster improved mobile services that can be used worldwide. An allocation was also made to support commercial telephone service between passengers flying on aircraft and individuals on the ground. Allocations were made for sound broadcasting from satellites, as well as for providing a means to accommodate a complementary terrestrial-based digital audio broadcasting service. New frequency allocations to support space activities were agreed upon, and an allocation was made to the fixed satellite service in the band 13.75 to 14.0 GHz     

How WARC '92 will affect mobile services

The US proposals to, and the decisions of, the 1992 World Administrative Radio Conference (WARC '92) that relate to mobile and mobile-satellite services are described. Mobile-satellite service (MSS) issues addressed at WARC '92 include new allocations for low Earth-orbit (LEO) satellite operations, new MSS spectrum allocations, and modifications to current allocations used to support mobile-satellite operations. Allocation issues on the agenda of WARC '92 that related to the terrestrial mobile services include allocations for mobile services between 1 and 3 GHz, allocations for aeronautical public correspondence, and designation of frequency bands for future public land mobile telecommunications services. A number of proposals which were put forward by the US to support MSS allocations and operations that did not explicitly require allocations to the MSS are discussed     

5 470-5 725 MHz频段气象雷达与WLAN共存干扰确定性分析

为了探索5 470~5 725 MHz频段作为移动接入候选频段的可行性,对该频段气象雷达与WLAN系统的干扰共存问题进行了确定性分析。通过搭建确定性计算仿真模型,确定干扰保护准则,得出在最恶劣情况下的频率距离间隔,为气象雷达与WLAN之间的共存干扰提供有效的预测方法。     

Feasibility of Coexistence of Mobile‐Satellite Service and Mobile Service in Cofrequency Bands

Interference scenarios and methodologies between a terrestrial mobile service (MS) system and mobile‐satellite service (MSS) system in a co‐channel environment are established. Taking into account a practical deployment situation for both systems, we perform computational simulation of interference in terms of carrier‐to‐interference ratio (C/I) and interference‐to‐noise ratio (I/N) to evaluate the cofrequency interference from an MS system into an MSS system, and from an MSS system into an MS system, respectively. The methodology and results can be used as a guide when planning the deployment of MSS and MS systems with no unacceptable interference impact between them.     

Capability of the FCC mobile monitoring van

The Spectrum Management Task Force of the Federal Communications Commission was formed, in part, for the purpose of devising new methods of spectrum management. Initial efforts have been directed toward improved spectrum utilization in the Land Mobile Service (which includes a large number of different types of users on approximately 2000 channels, assigned on a noncontinuous basis, on three bands (25 to 50 MHz or "low band," 150 to 174 MHz or "high band," and 450 to 470 MHz or "UHF band," with additional channels specifically provided by FCC action in the lower UHF television channels in certain metropolitan areas, and with additional frequency space to become available in the 900-MHz region, but with frequency congestion generally to be found in all large population centers, and apparent maldistribution of users Upon available channels). One technique which is being applied to the overall problem is the mobile spectrum monitoring van designed to measure occupancy, transmission, and other parameters of the land mobile channels.     

Coexistence conditions of LTE-advanced at 3400–3600 MHz with TVRO at 3625–4200 MHz in Brazil

In Brazil, the 3625–4200 MHz frequency band (C-band) is widely used by TV receive-only (TVRO) application in the fixed satellite service (FSS). The 3400–3600 MHz adjacent band can be used by International Mobile Telecommunications (IMT) systems, but many low noise block downconverters (LNB) of TVRO sold in Brazil have not a C-band filter. Thus, it is likely that the low cost LNB used in TVRO receivers would be overloaded by the IMT-systems emissions within the LNB wideband receiver, even the IMT stations operating accordingly to international standards. This paper shows that both systems can coexist harmoniously depending on the characteristics of the IMT system and on the FSS receiver specifications.