CMMB单频网超理论间距组网中同频干扰的研究

CMMB单频网组网时,15.36km的最大理论间距限制了单频网组网效率的进一步提升.文章通过理论分析总结在理想情况下超理论间距组网时同频干扰区域的位置和变化规律,并介绍了实际过程中调频干扰分析和优化的方法,为超理论间距组网情况下CMMB单频网规划、设计提供了理论指导.     

巴音郭楞电视台地面数字电视单频网建设

本文简述了在边疆少数民族地区组建地面数字电视单频网过程中的一些措施和解决方案,从单频网的突出优点、组网特点等环节详细介绍在组网过程中避免同频干扰的措施.     

国标地面数字电视单频网的组网与建设

在研究国内相关标准、技术的基础上,主要对地面数字电视单频网组网中涉及的关键技术单频网组网的同频干扰与建站距离等问题进行分析和阐述,并开发了采用两种机制的网络管理系统软件,解决了单频网组网过程中相关设备远程管理的问题。同时,介绍了山西省国标地面数字电视单频网的建设情况。     

CMMB超理论间距SFN设计的研究——CMMB下一阶段建网策略探讨

针对CMMB常规单频网组网所存在的一些突出问题,提出CMMB超理论间距单频网以及CMMB HSFN这两种组网策略.在对常规单频网分析的基础上,总结出CMMB超理论间距单频网设计的理论基础,并认为延时与同频干扰比(CIR)是设计这种单频网时需重点考虑的两个因素,进而对CMMB单频网进行超理论间距组网的可行性与工程设计、CMMB HSFN组网等进行了探讨.     

射频已调波技术在同步广播中的应用研究

应用同步广播技术构建单频网能够在一定程度上缓解频率频谱资源紧张的问题,并实现降低同频干扰,提高收听收看质量.本文首先分析了同步广播单频网的常见技术问题,随后对射频已调波技术理论做简要介绍,最后探讨了基于射频已调波方式的同步广播单频组网方法.     

ADTB-T单载波单频网应用及其实现方式

介绍了单频网基本原理,论述了扩大地面数字电视覆盖范围的途径、ADTB-T构建的单载波单频网的优势及如何最大限度消除同频干扰,以及在建设ADTB-T单频网宽频传输系统实际应用中应该注意的几个问题.指出在组网时,要从网络前期规划、站点分布、发射机选择、可能出现的同频干扰等多方面作好详细规划,才能在实际施工中有据可依.     

单频网建设原则及优化方法

在对单频网多年跟踪研究的基础上,首先总结分析了单频网建设的原则,以及单频网内产生自我同频干扰的条件,针对此类单频网的同频干扰现象,首次提出了单频网优化调整的指导思想和优化原则,在此指导思想和原则下,全面深刻地分析了单频网的各种优化方法和技术手段,为单频网的规划设计提供理论指导和思想借鉴。     

NB-IoT异频组网及优化策略研究

NB-IoT(窄带物联网)技术依附于800 MHz网络,射频带宽180 kHz,下行功率谱密度远大于LTE及CDMA网络,窄带特性及较强的功率谱密度导致单频组网下NB-IoT网络同频干扰现象严重。针对窄带同频干扰问题,提出异频组网策略,通过"双频组网策略、大间隔三频组网策略、无间隔三频组网策略"三种组网方式的验证及对比,提炼出一套适用于中国电信NB-IoT现网的异频组网策略,可以最大程度避免同频干扰,提升SINR(信干噪比)值改善用户感知。     

相位制中波同步广播单频组网及测试分析

中波同步广播单频网技术能够在一定程度上缓解频率频谱资源紧张的问题,并消除同频干扰.本文在简要介绍精密相位制中波同步广播技术理论的基础上,将重点对前期开展的基于这种高精密度相位制同步组网测试工作进行阐述.     

IP组播在CMMB单频网中的应用与实践

简要阐述了宁波多媒体广播(CMMB)单频网技术系统,详细介绍了TS over IP传输模式及IP组播方式在多媒体广播(CMMB)单频网组网中的技术方案,对单频网组网的传输模式提出了新的建设思路,对各地组建CMMB单频网具有参考和借鉴意义.     

Digital/analogue co-channel protection ratio field measurements

The digital terrestrial television standard approved by the European Telecommunications Standards Institute (ETSI) using coded orthogonal frequency division multiplexing (COFDM) facilitates the establishment of complex networks including single frequency networks (SFN) and multiple frequency networks (MFN). RTE and other partners of European Union (EU) sponsored projects such as MOTIVATE and VALIDATE have established and tested these networks in order to understand the important parameters of digital networks. Protection ratios are needed in order to plan the coverage of digital networks and minimise interference from co-channel transmitters. This paper describes a network established to field test protection ratios and details the measurements performed. Three co-channel UHF transmitters were installed at RTE mainstations in the Dublin area     

Co-channel interference canceller using CMA adaptive array antenna

A co-channel interference canceller that uses a constant modulus algorithm (CMA) adaptive array antenna is presented. In this canceller, when a CMA adaptive array antenna captures a co-channel interference signal, a replica of this signal is generated and then eliminated from a received signal, thus a desired signal can be obtained. Computer simulation results show that the proposed canceller can effectively reduce co-channel interference     

基于同道干扰统计模型的无线自组织网络性能分析

基于无线自组织网络中节点的分布特征,结合对同道干扰的定量分析结果,给出了 一种适用于无线自组织网络的同道干扰统计模型。分析了无线自组织网络中同道干扰的统计 特性,并基于建立的同道干扰模型研究了无线自组织网络的系统性能。结果表明,同道干扰 对无线自组织网络的系统性能有严重影响,需建立合理的干扰模型才能更准确地评估自组织 网络的系统性能。     

Channel estimation and interference suppression infrequency-selective fading channels

The issue of interference suppression is considered for wireless time-division multiple-access (TDMA) systems equipped with multiple receive antennas in frequency-selective fading channels. A novel scheme is presented to estimate the multipath channel, coherently demodulate information symbols, and meanwhile suppress radio interference. The proposed scheme is simple to implement and able to mitigate interference of various origins, including intersymbol interference, co-channel interference and others. Numerical examples are presented to illustrate the performance of the proposed scheme     

Elements of cellular mobile radio systems

A major concern in a cellular mobile radio system is the co-channel interference. Therefore, the reduction of co-channel interference becomes a main thrust for the system design engineers. We use the co-channel interference reduction factor as a design criterion and predict the signal-to-interference (S/I) ratios in different system configurations. The handoff mechanism and algorithmic considerations, the traffic capacity and procedure for splitting cells, and the near-end-to-far-end ratio interference and reduction are the elements described.     

同信道干扰对多载波CDMA蜂窝系统下行信道的影响

该文主要讨论多载波CDMA蜂窝系统在下行信道中的同信道干扰问题,理论分析了同信道干扰的解析表达式,并通过计算机仿真得出了在一定的传播损耗下多载波CDMA蜂窝系统下行信道的性能。通过仿真发现,即使在有小区间同信道干扰情况下,通过简单的小区布置,多载波CDMA蜂窝系统下行信道就可以有很大的信道容量。     

Dispositifs de compensation de l’interférence due au signal en polarisation croisée dans un canal radioélectrique avec réutilisation de fréquence

An overview of the countermeasure techniques used in digital radio links for combatting the effects of co-channel interference in dually polarized channels is presented. Their way of acting and their performance are presented, as well as the propagation models used for their study.     

数字电视接收机中降低同频干扰的方法

提出一种数字电视接收机中消除模拟同频干扰的解决方案.经过实验室测试和现场路测证明,该设计结构与均衡器结合,在采用16QAM时,可降低9 dB的同频干扰,采用4QAM时,可降低14 dB的同频干扰.     

存在共道干扰的多径衰落环境中手机双天线系统性能研究

将城市室外电波传播模型、手机天线本征激励方向图以及信号合并方式相结合,建立了分析在具有共道干扰的多径衰落环境中手机双天线系统的性能模型。用这一模型研究了采用最优合并方式的手机上双单极子天线系统的性能,分析了合并性能受共道干扰强度、天线互耦以及机身的影响。     

Performance Analysis of Rayleigh Fading Channel in the Presence of Co-channel Interference with Multiple Interferers Under Different Adaptation Policies

In this paper, an approach to performance analysis on signal-to-interference ratio operating over Rayleigh fading channels experiencing an arbitrary number of multiple, Rayleigh co-channel interferers is presented. We have presented a general analysis of selection combining, where each branch experiences an arbitrary number of multiple equal power co-channel interference. Useful closed-form expressions are derived for the probability density function and cumulative distribution function at the output of the combiner. Also, outage analysis is performed in order to show the effects of interferers and diversity order. Capacity per unit bandwidth expressions are derived for selection diversity scheme under different adaptation policies.