Performance Analysis of Downlink MIMO WCDMA Systems Using Antenna Selection in Transmitter and MRC Plus LDD in Receiver over Correlated Nakagami-Fading Channels

In this paper bit error rate (BER) performance is analyzed for multiple input-multiple output (MIMO) communications systems using antenna selection in the transmitter, maximal ratio combining (MRC) and linear de-correlating detector (LDD) in the receiver in wide band code division multiple access (WCDMA) downlink channels with correlated Nakagami fading. The MRC maximizes signal to noise ratio of the received signal, then the LDD cancels out multiple access interference (MAI). Theoretical results are validated using computer simulations. Moreover, a pilot based estimation method is proposed to jointly estimate the channel gains and the rows of the LDD operator. Simulation results show that using this proposed method, diversity order is maintained in the receiver. Furthermore, our analysis shows the spectral efficiency degradation due to the pilot based strategy is negligible.

Handover initiation performance of a new multi-cell cellular configuration with a developed base-station multi-beam antenna

A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of the received signal power in the mobile station, including both desired and interference signal power, has been introduced into the handover initiation algorithm. Along with the idea, we present three models of handover initiation algorithm with the shadowing process of Gaussian distribution. The formulation of handover initiation probability of those algorithms is also analyzed. The validity of the presented models has been checked through the comparison with simulation results. The results present the performance characteristics of handover initiation vary with cluster number and base-station antenna elevation angle.

Impact of Phase Noise on TDMS Based Calibration for Spaceborne Multi-Beam Antennas

For spaceborne multi-beam antennas(MBAs), time division multiplexed switching(TDMS) based calibration receiver can reduce implementation costs effectively and is very suitable for large-scale applications. However, in practice, random phase noise imposed by noisy local oscillators can cause significant performance degradation in TDMS-based calibration systems. Characterization of phase noise effects is therefore crucial for practical applications. In this paper, we analyze the impact of phase noise on the calibration performance for a MBA system. Specifically, we derive the relationship between the probability of correct amplitude/phase estimation and various practical factors involving the signal-to-noise ratio(SNR), the standard deviation of phase noise, the given tolerance region, and the length of the spreading code. The results provide high efficiency for evaluating the calibration performance of the MBAs based on TDMS, especially for precisely anticipating the impact of phase noise. Finally, the accuracy of the derived results is assessed by simulations in different scenarios.

中波广播发射机的原理及应用

中波广播发射机作为广播传输的一种技术手段,对于广播行业的发展起着重要作用。深入研究中波广播发射机的原理和应用,并探讨其在广播行业中的重要性。首先,介绍中波广播发射机的基本原理,包括音频信号的调制与解调、射频信号的产生与放大、天线辐射等关键技术。其次,探讨中波广播发射机在广播行业的应用,包括广播覆盖范围的选择、信号质量的优化及干扰抑制等方面。最后,列举中波广播发射机在电台广播、天气广播、教育广播以及文化传播等特定场景的应用案例。

中波发射台天馈线系统的维护与管理

天馈线系统是中波广播发射系统的重要组成部分,也是中波发射台的主要设备之一。基于此,首先介绍中波发射台天馈线系统的构成,然后针对当前广播电视设施维护的严格要求,提出具体的管理措施,包括注重日常保护、严格执行机房值班制度及制定应急预案。

中波发射机双频共塔天线调配网络设置与优化

着眼于天线调配网络的关键组成部分,提出一种模块化的设计策略,以简化天线调配网络的设计,优化其结构,提高系统调试与维护的效率。详细探讨阻塞网络、吸收网络和防雷网络的设计原理及实现方式,最终形成一种针对特定频率的等效天线匹配网络设计方案,旨在为中波发射机的调配网络设计提供有益参考,促进无线电信号的高效、稳定传输。

广播中波发射台三台发射机天线倒换开关设计与实现

两台发射机天线倒换开关只考虑一次倒换,倒换原理简单易操作。增加一台发射机,安全播出任务更有保障。为此,分析三台发射机天线倒换开关的设计需求,介绍倒换开关关键设备陶瓷真空继电器,详细介绍三台发射机天线倒换开关整体结构、关键设备及连接原理,阐述三台发射机的倒换流程。

中波发射机双频共塔天线调配网络分析与调试研究

中波发射机双频共塔天线调配网络的设计与优化对于提升天线系统综合性能具有重要意义。为给中波发射机双频共塔天线调配网络的工程设计提供重要参考,探究中波发射机双频共塔天线调配网络设计、调试与测试,并从带宽与增益、互调失真与谐波抑制、系统效率与可靠性等方面分析中波发射机双频共塔天线系统的性能评估方法。

高压电力传输设备对中波发射台覆盖效果的影响分析

某中波发射台附近拟架设高压电力传输设备,为研究其对中波覆盖效果的影响,开展专题研究。在电磁仿真软件中建立仿真模型,分析不同数量、高度和距离的电力塔对中波天线水平面方向图的影响,最后总结出一般规律,为项目的建设提供参考。

中波台两种报警电路设计思路及工作原理分析

本文对甘肃省广播电视局白银广播转播台设计安装的天调室防盗报警电路、DAM数字调幅发射机掉高压报警电路工作原理进行了详细的介绍,主要谈到它的设计目的和工作原理,以供同行参考。

中波广播发射系统中天馈网络的基本原理及维护

随着广播技术的快速发展,中波广播发射系统(以下简称发射系统)在广播领域的应用日益广泛。天馈网络作为发射系统的关键组成部分,对于提高信号传输效率和稳定性具有重要意义。文章主要对基于10 kW中波广播发射机(以下简称发射机)搭建的发射系统中的天馈网络部分进行分析,介绍了发射机的基本原理,并且从基本原理、结构特点、优化方法等几个方面对天馈网络进行了分析,最后总结了根据实践经验得出的天馈网络维护方法,旨在为发射系统的优化设计和运行维护提供理论支持与实践指导。

高山无线发射台的卫星接收天线防雷技术分析

阐述雷电的形成、危害和入侵途径,分析高山无线发射台防雷接地中的问题。提出雷电防护措施,包括严格要求发射塔避雷针的保护范围、电源前安装压敏电阻等避雷装置、中继传输的保护。

基于多网合一的无线室内分布系统设计

文章提出一种基于多网合一的无线室内分布系统设计,简单分析多网合一模式后,探讨室内无线分布系统中应用多网合一模式的意义。然后分析收发分缆合路方式、合用天馈收发合缆方式下的多网合一室内无线分布系统设计方式,探讨当下多网合一期间广泛存在的不同设备频率匹配问题和信号干扰问题,为其他研究人员开展无线室内分布系统设计工作提供借鉴。

Dual-band multi-beam reconfigurable terahertz antenna based on graphene frequency selective surface

In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is analyzed.By adjusting the bias voltage to control the graphene chemical po-tential between 0 eV and 0.5 eV,the GFSS can achieve four working states:dual-band passband,high-pass lowimpedance,low-pass high-impedance,and band-stop.Based on this GFSS,a hexagonal radome on a broadband omnidirectional monopole antenna is proposed,which can achieve independent 360°six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual bands.In addition,while increasing the directionality,the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi,respectively.This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.

Multibeam Antenna Based on Butler Matrix for 3G/LTE/5G/B5G Base Station Applications

With the rapid development of mobile communication technology and the explosion of data traffic,high capacity communication with high data transmission rate is urgently needed in densely populated areas.Since multibeam antennas are able to increase the communication capacity and support a high data transmission rate,they have attracted a lot of research interest and have been actively investigated for base station applications.In addition,since multi-beam antennas based on Butler matrix(MABBMs)have the advantages of high gain,easy design and low profile,they are suitable for base station applications.The purposes of this paper is to provide an overview of the existing MABBMs.The specifications,principles of operation,design method and implementation of MABBMs are presented.The challenge of MABBMs for 3G/LTE/5G/B5G base station applications is discussed in the end.

中波广播天线倒换系统的设计与实现

天线倒换系统作为主、备发射机与天线、假负载间必不可少的转换装置,其可靠性与经济性事关中波发射台能否实现“高质量、不间断,既经济又安全”的播出。本文详述了我台天线倒换系统各部分的结构及实现方法,该系统耐高频高压且工作可靠直观,为同行提供了一个可行方案。

新一代多普勒天气雷达强度定标研究

天气雷达回波强度的强弱直接影响预报员对降水强度的判断,在重大气象灾害天气过程中,回波强度偏差有可能导致漏报而产生无法挽回的损失,中国气象局提出“到2022年底全国新一代天气雷达反射率因子标准偏差平均值从4.5 dB降低到3.5 dB”的目标,就是为了提高雷达监测均一性,降低客观因子对预报质量的影响。该文对岳阳、长沙、湘潭、益阳雷达产品对比分析,利用数据平均偏差方法计算雷达回波强度的扩散特征,得出岳阳雷达回波强度较其他3部雷达均偏弱约4 dB以上的结论,并采用“对点测量”方法对岳阳雷达进行重新标定,将平均偏差降低至2.5 dB以内,有效降低了中尺度区域内不同雷达之间的平均偏差,增强了回波强度一致性,对提高雷达业务可用性具有重要的现实意义。

电磁耦合谐振电路在中波天调网络中的应用

本文对边频反射引起的问题进行了说明,并分析了产生边频反射的原因,着重分析了三种解决办法存在的不足。针对此问题,提出了采用电磁耦合谐振电路设计天调网络的办法,并介绍了其工作原理及实际应用案例。此方法具有显著的优势,可为存在边频反射问题的中波广播转播台提供借鉴和参考。

数字调制中波发射机输出监测电路工作原理

数字调制中波发射机也称DAM中波发射机,具有保护功能完善、工作效率高的特点。多年的维修实践表明,中波发射机输出调谐电路故障和天馈线系统故障为多发故障,如果处理不及时,会烧坏功放器件。对此,数字调制中波发射机专门设计了一块输出监测板,对输出调谐电路和天馈线系统工作状态进行监测。当有驻波故障出现时,发射机做出相应的保护措施,确保发射机安全。以GZ-GS10 kW发射机为例,对输出监测板的工作原理进行详细论述。

中波广播发射台搬迁及天线建设策略

中波广播发射台是用于广播信息传输与共享的平台和系统。随着广播信息传输需求的变化,可能需要对原有的中波广播发射台进行搬迁和改造,以更好地满足信息传输的要求。而中波广播发射台结构的复杂性和运营要求的高标准,对发射台的搬迁及相关建设提出了较高的要求。基于此,在概括介绍中波广播发射台的基础上,就其搬迁策略以及天线建设策略进行探讨分析,为中波广播发射台的搬迁与改造提供经验参考。