TD-SCDMA系统中一种软件集成智能天线算法

给出了一种采用信干噪比准则的、集成了预多波束天线与LMS自适应天线的软件天线方案,该方案采用开关合并方法,把软件天线输出接到最大输出信噪比的算法输出,实现算法分集.在TD-SCDMA动态模型上对提出的方法进行了仿真,结果表明,采用集成软件天线方案的误码率性能要优于单纯的预多波束天线或LMS自适应智能天线.仿真过程考虑了用户来波方向和用户到基站距离的动态变化,以及功率控制算法和系统同步过程的影响.     

B3G中的多跳蜂窝小区的结构分析

基于多跳通信及蜂窝通信的特点,提出了一种由中心基站及其周围的固定多跳中继节点共同实现小区覆盖范围的多跳小区结构。在此结构中,基站附近的移动台以一跳方式直接接入基站,而距离基站较远的移动台通过其与基站之间的多跳中继节点的中继以多跳通信方式接入基站。该结构提供了在低成本及低发射功率条件下完成区域覆盖的方法。并对多跳小区结构的覆盖特性进行了分析,通过仿真计算给出了多跳节点数目与小区覆盖范围的关系。     

协同MIMO系统中的自适应用户数选择算法研究

提出了一种在协同多入多出(Co-MIMO,collaborative MIMO)系统中的自适应用户数选择算法.基站向调度器报告各个移动台从本基站接收到的信号、干扰及噪声功率,调度器据此计算各个基站支持用户数的最佳方案,反馈给相应的基站.自适应方案根据信道的变换灵活改变基站和移动台之间的从属关系,达到有效降低小区边缘用户的小区间干扰、优化小区边缘系统容量的目的.仿真结果证明了在发射端多用户预编码下自适应支持用户数选择算法相对于支持固定用户数的优势.     

基于自适应扩展单元的微微小区无缝覆盖

针对60GHz RoF(光载无线网络)微微小区,提出了一种新的基于自适应扩展单元的切换方案,用于实现微微小区的无缝覆盖.自适应扩展单元就是动态地将用户当前所在小区及其周围相邻的小区虚拟地构建成用户当前的扩展单元,随着用户的移动,扩展单元也不断重新构建.通过建立仿真模型,验证了自适应扩展单元切换方案的低掉话率和丢包率.     

基于CDMA蜂窝移动通信小区分裂研究

通过对CDMA蜂窝网络中小区分裂的网络覆盖问题分析，结合现有无线网络覆盖，指出分裂后反向与前向覆盖不一致的原因并深入挖掘了反向链路容限增益动态的性质；利用Kalman盲信号多用户检测算法对信号的接受机处理高增益的优点，提出适合于现有基站工程的方案；该方案成功地解决了分裂后的蜂窝小区反向与前向覆盖不一致问题；最后指出该方案的发展前途。     

星载多波束天线设计

给出了星载多波束天线的设计方法、步骤和参数选择原则，给出了两个区域多点波束天线和赋形波束的设计实例，并用物理光学法计算了覆盖区域的天线方向图、覆盖区增益和频率复用时的同极化波束隔离。     

高层建筑内网络覆盖系统的建设

对于运营商来说，室内覆盖系统需要解决的不仅是室内盲区的覆盖问题，更重要的是室内覆盖不好出现手机掉网．高层空间无主控小区导致频率干扰严重．室内话务量吸收等问题。为解决这些问题，目前最有效的方法就是建设室内分布系统，将基站的信号通过有线方式直接引入室内的每一个区域，再通过小型天线将基站信号发送出去，从而达到消     

三角形蜂窝小区的遍历信息论容量分析

三角形小区通信系统（TCCS）是一种新型分布式基站（BS）通信系统。小区结构为正三角形,分为3个单一覆盖区（UCR）和1个交叉覆盖区（CCR）。移动台（MS）在单一覆盖区内只与邻近的BS通信,在交叉覆盖区内与小区所有3个基站通信。在该小区结构的基础上,该文提出了在单一覆盖区内采用频率复用,在交叉覆盖区内采用宏分集的频率规划方案。在这种规划方案和每根天线最大发送功率限制下,计算了多小区环境下TCCS在MS单天线和多天线时的遍历容量,与相同条件下的广义分布式天线系统（GDAS）作了比较,结果显示在各种情况下,TCCS的容量相对于GDAS都有显著的增益。     

蜂窝小区边缘同频嵌入垂直覆盖的网络性能

提出一种在蜂窝小区边缘同频嵌入垂直覆盖的新型混合小区网络结构,具有抑制小区间干扰和提高边缘信干比等优点。该网络结构是以不改变目前蜂窝网络“水平覆盖”结构的前提下,在小区边缘干扰区域同频嵌入天线波束为垂直向下的微小基站,称作“垂直覆盖”,因此易于实际操作和实现。首先分析了蜂窝小区水平覆盖的干扰深度,垂直覆盖基站的干扰特性,及各自的频谱效率。随后,针对提出的蜂窝小区边缘同频嵌入垂直覆盖的网络结构,分别研究了混合小区的水平覆盖中心区域和垂直覆盖小区边缘区域的频谱效率。结果表明,提出的新型混合小区网络结构,能有效抑制蜂窝小区间干扰,改善小区边缘性能,实现更高的频谱效率。     

基于AI的全场景智能基站节电系统设计与实现

摘 要：在集约化网络的建设背景下,如何实现自动化、智能化、保体验的基站能耗管理,成为当前运营商的运营管理痛点。创新地提出一种全智能检测、全场景建模、全流程自助的3G/4G/5G智能基站节电方案,通过动态时间规整算法区分覆盖场景,利用SARIMA模型预测时间框构建自适应模型,实时监控指标保证用户感知,自动下发节电策略,短信告警及时拉起。在用户无感知的情况下,实现小区粒度级最大限度节约基站能耗。该方法已在某省网络试点推行,试点区域单站平均节电效率可达9.24%每日,具备实际生产指导意义。     

Performance Analysis of a Sectorized Distributed Antenna System with Reduced Co-Channel Interference

1IntroductionThe next generation mobile communication systemissupposedto provide high data rate services such as Inter-net access and multi media applications whichare morelikelyto be affected by Inter-Symbol-Interference(ISI)inwireless multi-path fading …     

一种宽带数字相控阵天线比幅曲线的设计方法

随着宽带数字化技术的发展,如何利用宽带DBF 技术在电子对抗领域中进行精确测角测向一直是研 究的热点。文中论述了一种宽带数字相控阵天线比幅曲线的优化设计方法,从多波束类型的选择出发,分析了和和 交叠电平的选择、空域覆盖和增益覆盖的取舍等问题,并且通过对雷达探测领域和差比幅曲线绘制方法的演化,得 到宽带数字和和比幅曲线的绘制方法,分析了基于正弦空间的多波束比幅曲线、中心频点的频率转移、侦察频点的 频率转移等问题,最终仅用一条标准比幅曲线进行装订即可解决宽带带宽内和扫描空域内的所有和和比幅测角问 题,该设计方法拟制的宽带多波束比幅曲线,可应用于宽带数字相控阵体制的雷达探测或电子对抗领域,在简化比 幅曲线数量、减少比幅曲线存储空间、提升比幅测角测向精度等方面均有明显的优势。     

Tradeoff Analysis of Fixed Cell Assignment in Wideband TDMA Networks

This paper analyzes tradeoffs within a dynamic allocation method, called the fixed cell assignment, which employs wideband time division multiple access transmission for the forward link in broadband (10 Mbit/s) wireless networks. This high data rate at the operating frequency 2 GHz is considered. The system is configured with directional base station antennas and omnidirectional mobile antennas, with each cell divided into six sectors, and sectors numbered in the same order for every cell. Access is controlled based on availability and sector number, and half the sectors in each cell reuse the same spectrum. The frequency reuse factor of two and power control technology mitigate the effects of co-channel interference. Differential phase shift keying modulation is employed. Computer simulations are performed showing maximum capacity tradeoffs.     

Synthesis of spacecraft array antennas for intelsat frequency reuse multiple contoured beams

A method is described for synthesis of planar array antennas where both the amplitude and phase of each radiating element is a design variable. The method improves the computational efficiency of conventional optimization procedures based upon, for example, minimax or least square algorithms. Application of the proposed method demon-strafes the feasibility of spacecraft frequency reuse array antennas with multiple contoured beams for typical Intelsat sixfold frequency reuse requirements. It is demonstrated that repetitive optimization will reduce the number of array elements required. Shifting the array aperture normal toward a beam center will dramatically improve the frequency sensitivity of the beam coverage.     

A MAC protocol for the mixed scenario of omnidirectional and directional nodes in an ad hoc network

In ad hoc networks, directional antennas offer many benefits compared with classical omnidirectional antennas. Those include significant increases in spatial reuse, coverage range, and subsequently network capacity as a whole. Most of the proposed directional medium access control methods assume that all the nodes in the network have homogeneous antenna types. However, it is quite unusual that a sudden change will occur, and every laptop, palmtop, computer, and other similar device will be turned into a directional antenna holding device. There will always be a possibility of heterogeneous antenna used in the deployed nodes of the network. In this paper, we have proposed a medium access control protocol that deals with the new challenges introduced into heterogeneous networks in the form of deaf and hidden node problems. Using Optimized Network Engineering Tools 16.0, we have simulated three ad hoc network scenarios. These scenarios have different ratios of omnidirectional and directional nodes. We evaluated the performance of these scenarios by varying the ratio. We found that when we increase the directional nodes in the network, the performance increases. Copyright © 2013 John Wiley & Sons, Ltd.     

Scan limitations of shaped dual-offset reflector antennas for multiple satellite access

The performance of offset Cassegrain antennas, shaped to provide wide scan angles, is outlined for use in earth stations which are capable of accessing several satellites simultaneously. The effect on the beam efficiency of scanning over a rectangular-shaped coverage region located about the geostationary arc is described. Limitations on scan performance are discussed as is the effect of satellite tracking by feed movement.<>     

MARS: a multiple access scheme with sender driven and reception first for smart antenna in ad hoc networks

The deployment of directional antennas offers many advantages, such as transmission range extension, co‐channel interference reducing, the increasing of spatial reuse degree, throughput improving of networks, and transmission power saving. Hence, many ad hoc MAC protocols with directional antennas have been proposed. However, these protocols do not provide significant improvement of network performance due to the lack of supporting multiple transmissions and receptions simultaneously. With the adaptive beam‐forming system (Smart Antenna), a newly designed MAC protocol (MARS) that enables nodes with multiple transmissions and receptions is proposed. Simulation results show that our MARS do exploit the advantage of space division multiple access. In terms of total number of data forward and complete sessions in bottleneck nodes, MARS achieves three times better than Novel and nine times better than IEEE 802.11. In addition, the end‐to‐end delay keeps very short. Copyright © 2008 John Wiley & Sons, Ltd.     

基于超表面的天线多波束偏转技术研究北大核心CSCD

5G移动通信对天线提出了多极化、多频段、多波束等更高的技术需求。超表面具有很强的电磁调控能力,利用这一特性可以实现天线多波束偏转。本文首先提出新型的基于行波激励网络的双波束偏转方法,利用超表面实现定向波束可控,设计了单频低副瓣高增益的双波束超表面天线。其次,提出基于多相位自由度理论的双频行波激励网络,结合双频超表面,设计了双频双波束偏转角可独立控制的超表面天线。在此基础上,提出基于正相位响应理论的稳定波束偏转角的方法,设计了具有稳定波束的±45°双极化超表面天线。与传统多波束方法相比,本方法省略了复杂的波束形成网络,设计简单、结构紧凑,而且能够实现双频、双极化等特性,可为新一代移动通信天线的研制提供技术思路。     

Cooperative communications for LTE‐advanced—relay and CoMP

The Long Term Evolution‐Advanced (LTE‐A) system is currently under development to allow for significantly higher spectral efficiency and data throughput than the LTE systems. In a wireless system based on orthogonal frequency division multiplexing with frequency reuse factor one, the achievable cell spectral efficiency is often limited by the inter‐cell interference or coverage shortage of base stations. In LTE‐A, coordinated multi‐point transmission/reception (a.k.a. multi‐cell MIMO or base station cooperation) and relaying technologies are being introduced to clear these major performance hurdles. In this paper, cooperative communication technologies being discussed in LTE‐A systems are presented, together with considerations on system design. Copyright © 2012 John Wiley & Sons, Ltd.     

Cochannel Interference in Cellular Fixed Broadband Access Systems with Directional Antennas

The Cellular Fixed Broadband Access System for LMCS (Local Multipoint Communication Services) is aiming to provide broadband services to fixed subscribers through wireless access. A representative LMCS scenario involves a cellular system design with the entire allocated bandwidth being used in each cell and with a highly directional antenna employed at the subscriber. The LMCS system designs rely on assumed information regarding radio propagation phenomena in the anticipated coverage areas. The research reported here, therefore, has the objective of verifying such information by theoretical modeling and simulation. Simulation and analysis have been used to study the effects of a number of factors on the system performance and interference characteristics of such a LMCS system. The investigated factors include beamwidth and gain ratio of directional antennas, sectorization of hub antennas, propagation exponent, lognormal shadowing, site diversity and transmitter power control. Both models of LOS (line of sight) and NLOS (non-line of sight) have been investigated in this work. The simulation results demonstrate that highly directional antennas at the subscribers can dramatically improve the system performance for both uplink and downlink. The system design with frequency reuse of one is examined, and it is confirmed that an outage of 0.9% for a NLOS system could be achieved by using narrow beam antennas of 3 degrees with site diversity and power control techniques employed. Under the condition of LOS available for the desired links, the outage can be expected to be as low as 0.3%.