哈尔滨地铁1号线工程公用通信隧道区间无线覆盖中继设置测算

介绍了地铁通信工程利用宽带POI设备对三大运营商通信网络信号进行合路处理后实现无线覆盖的基本方式,结合哈尔滨地铁1号线工程实例,重点阐述了不同的网络制式信号通过漏泄电缆在隧道区间传输和覆盖时,中继距离的计算方法.     

基于最小覆盖的多点中继集及其选择算法

多点中继广播机制是无线mesh网络中一种高效的广播方法.但由于不同1跳邻居节点对相同2跳邻居节点的重叠覆盖,当前基于图论最小控制集理论的多点中继集易造成无线资源的浪费.定义一种使网络中重叠覆盖数量最少的多点中继集,并提出选取这样的多点中继集的快速启发式算法.通过仿真结果证明使用重叠覆盖数量最少的多点中继集能够有效利用无...     

可增强信号覆盖范围的放大型信息超表面设计

传统信息超表面能对电磁波的幅度和相位做出动态调控,在无线中继中控制电磁波的传播方向,但并不能放大入射波的能量,因此这类超表面的工作距离受限,往往要通过较大的阵面面积来实现信号盲区的有效覆盖。为解决这一问题,提出了一种放大型信息超表面,并通过仿真验证了该信息超表面在2.7～3.1 GHz的宽带范围内具有2 bit的相位调制特性和信号放大能力。同时,通过引入功率分配和功率合成网络,使8个超表面单元组成一个1×8的阵列且只需使用一个放大器,以减少放大器的数量,从而降低硬件成本和系统能耗。仿真结果表明,所提出的放大型信息超表面阵列在宽带范围内同时实现了波束成形和信号能量放大,可应用于基于信息超表面的新型无线中继系统中,为增强无线信号覆盖和减小超表面阵面尺寸提供了一种全新的解决方案。     

宽带无线电基于中继的布网概念

近年来，在工业界和学术界，人们对多跳延伸的基础网络都很感兴趣．如3GPP中的种概念．IEEE 802.16网状网络、HiperLAN／2通过中继或用户合作分集的网状网延伸覆盖等。本文是对无线界研究论坛第四工作组的大量研究工作和其他人研究工作的综合论述．介绍了重要论题和以中继为背景的应用的评述，文章涵盖了利用多跳中继通信的多种方法．如延伸移动和无线宽带蜂窝网距离的方案（距离对容量的平衡办法)，在高频对抗阴影的方案等。说明了中继是一种降低基础设施部署成本的手段．并指出通过利用空间分集多跳中继可增大蜂窝网的容量，尽管这篇文章着重讨论固定中继，它所介绍的许多概念亦可用于移动中继系统。     

无线中继技术在TD-LTE网络中的应用分析

无线中继(relay)能够解决由于传输无法铺设、宏基站站址物业难以协调、高楼遮挡等导致的覆盖存在盲区的问题.应用实际外场测试与网络仿真两种手段,综合评估室外覆盖、室内盲区场景下中继的覆盖性能.通过分析中继与楼宇之间的距离、中继部署位置高度与室内深度覆盖效果之间的关系,给出中继用于解决深度覆盖盲区时的部署建议.     

基于nRF24L01模块的中继协作通信系统设计与实现

设计一种基于n RF24L01无线射频模块的中继协作通信系统,研究中继协作传输相比于直传链路的系统性能。利用无线射频模块和STC89C51组成硬件系统实现数据收发和转发,阐述系统电路设计和软件设计的实施关键。以降低系统误码率为目标,最大限度减少信道中噪声干扰和信号衰减程度。测试实验结果表明,使用该系统实现的中继协作通信具备更强的抗干扰性能,提升了通信的整体质量。     

基于增强学习的协作通信中继选择方案

中继方案的选择对无线资源有效利用尤为重要，本文我们提出了一个通过使用Q学习算法的高效无线协作网的中继选择方案。该方案中，通过我们定义的状态、动作和达到到良好SER（误符号率）表现时的回报来选择少量中继参与合作。仿真结果表明，相对于通过数学分析得到中继最佳数目的方案，该方案能通过使用更少数目的中继达到具有更可比性的SER性能，从而更有效地使用资源。仿真结果表明该方案可以被认为是一个很好的对未来通信的尝试。     

健伍手持对讲机录音中继控制器DIY

业余搭建无线对讲机中继,一般至少需要一台接收机和一台发射机,再加上双工器以及收发天线、连接馈线、供电电源等,不但原材料数量多,而且设备安装繁琐,指标调整困难,即便采用成品中继,也不免显得粗大笨重,固定工作倒没有什么,一旦需要移动位置既费时又费力.可现实生活中往往又离不开这样移动的临时中继台,譬如发生洪水、地震、飓风等自然灾害,或者出现森林大火、高山雪崩、毒气泄漏、建筑坍塌等重大伤亡事故,如果目常的基础通信设施遭到破坏陷入瘫痪,为应对现场错综复杂的混乱局面,彼此协调统一行动,共同抵抗灾害挽救事故,尽最大可能保障人民群众的生命与财产安全,此时利用便携武移动中继快速建立应急通信就成了首要任务.本文介绍一款录音中继控制器,配合平常使用的健伍手持对讲机,就能构成了一台小巧的录音中继,只要将它安放到四周开阔远近适中的制高点,与其它对讲机一起就可马上组成一个高效的远距离通信网络,关键时刻发挥出难以匹敌的作用.     

无线小区固定中继选择算法及仿真

为了使相同成本的小区无线覆盖性能达到最大化,在研究了固定中继的无线小区系统后,提出一种简化动态中继选择算法的途径。仿真中继选择算法对系统性能的增益,证明固定中继系统较无中继系统在性能上有极大的提高;同时,还通过比较简化的中继选择算法和相应的原算法的仿真结果,说明简化算法减少了实现的复杂度,降低了通信损耗,而在性能上基本不受影响。     

管理动态

黑龙江大兴安岭无管机构及时查明森林防火通信频率受干扰原因,随着春季森林防火期的日益临近,黑龙江省大兴安岭无线电管理机构实行24小时监测值班,加强了对重点无线电业务的监测和数据分析,确保防疫、防火等重要无线电业务安全。3月10日,地处全国森林火灾高危区的黑龙江省大兴安岭加格达奇林业局防火办向大兴安岭无管机构投诉,称防火专用超短波无线通信网某中继频率受到不明广播信号干扰,致使市区内所有使用该中继的防疫、防火对讲机无法正常通信。     

On the MAC-BC duality of multiuser non-regenerative MIMO relay systems

Multiple input multiple output(MIMO) relaying techniques can greatly improve the spectral efficiency and extend network coverage for future wireless systems.This article investigates a multiuser MIMO relay channel,where a base station(BS) with multiple antennas communicates with multiple mobile stations(MS) via a relay station(RS) with multiple antennas.The RS applies linear processing to the received signal and then forwards the processed signal.The dual channel conditions between MIMO relay multiple access channel(MAC) and broadcast channel(BC) are first developed for single-relay scenario with white Gaussian noise.Then the MAC-BC duality for MIMO relay systems is established by proving that the capacity region of MIMO relay MAC is equal to that of dual MIMO relay BC under the same total network transmit power constraint.In addition,the duality is also extended to multi-relay scenario with arbitrary noise.Finally,several simple general numerical examples are provided to better illustrate the effectiveness of the MIMO relay MAC-BC duality.     

无线中继在下一代移动通信系统中的应用

无线中继是一种接收其他站点无线信号,并根据接收到的信号生成自身发射信号的装置,下一代移动通信系统中会大量运用一种decode-forward模式的无线中继.这种中继本身有相对简单的协议栈,对接收信号进行解调和基带处理,然后生成发射信号.根据中继协议栈的完备程度,这种中继可以完成差错控制、功率调整、信道测量、干扰协调,甚至有调度功能.本文主要介绍无线中继对移动通信系统的影响、应用场景、相关技术,标准化组织和研究组织对其研究的进展.     

WIFI多级桥接应急多媒体通信系统研究

聚焦北京地铁交通轨道应急抢险可视化通信与信号传输的应用领域，针对传统的有线通信系统存在的传输距离短、线路铺设灵活性差；无线通信系统中，无线自组网技术存在的收发单元间传输能力与适应性差；卫星与公网结合的通信系统存在的信号源不稳定等缺陷。提出了WIFI多级桥接应急多媒体通信系统架构，研究基于5.8GHz的WIFI多级接桥技术并研制相关设备，在无线自组网技术基础上，在传输能力与适应性方面进行了改进，能够有效适应远距离、遮挡及垂直差异存在的信号传输场景。提出采用广泛应用的公网4G信号构建通信系统，有效避免当车载基站作为信号源造成的不稳定性，当应急救援现场无4G信号覆盖时，结合WIFI多级桥接技术提供的网络传输保障功能，从而使得整体桥接与通信系统可满足所有的地铁抢险环境并实现相应功能要求。      

Cellular CDMA capacity with out-of-band multihop relaying

In this paper, we consider the capacity of cellular code division multiple access (CDMA) when there is out-of-band ad hoc traffic relaying. The mobile stations (MSs) are dual-mode, having both ad hoc and cellular CDMA radios. An active MS is free to choose any available relay station (RS) within its ad hoc radio coverage area for dual-hop communication with the CDMA base station (BS). Communications between the RSs and the MSs use bandwidth which is available to the ad hoc radio and does not consume the CDMA capacity. Using this mechanism, CDIVIA interference can be reduced by dynamically selecting RSs which have more favorable CDMA link characteristics. Several relay station selection criteria are considered, namely, ad hoc relaying with low relative interference (ARRI), with best link gain (ARLG), and with shortest distance (ARSD). The relay station selection protocols are compatible with existing wireless local area network (WLAN) standards such as IEEE 802.11. An analytic model is used to compute the effects on uplink and downlink CDMA capacities when out-of-band relaying is added. The results show that very significant capacity improvements are possible by using these criteria compared with conventional CDMA with hard or soft handoff. Ad hoc relaying which dynamically tracks CDMA link quality can achieve greater capacity improvements than that using a distance-based relay station selection. Relaying, which considers both signal and interference conditions, achieves better capacity than that based on signal link quality alone.     

Design of optimal relay location in two-hop cellular systems

Relay stations are usually used to enhance the signal strength for the users near cell boundary, thereby extending the cell coverage. However, transmission through a relay station needs two transmission phases. The first phase is from base station to relay station, and the second one is from relay station to mobile station. Thus, using relay station may decrease system capacity due to two-phase transmission time. As a result, whether or not data are transmitted by one-hop or two-hop phases should be determined according to both signal strength and throughput. In this paper, we investigate the optimal relay location aiming to maximize system capacity. We consider two relay selection rules for determining whether two-hop transmission will be used: signal strength-oriented and throughput-oriented selection rules. We find that the signal strength-oriented two-hop transmission may yield even lower system capacity than the one-hop transmission. In the throughput-oriented scheme, the two-hop transmission can achieve higher system capacity than the one-hop transmission. By simulations, we determine the optimal relay location and show the coverage enhancement by the relaying network. Extensive simulations are performed to investigate the impacts of relay transmission power and the number of relay stations on system capacity and optimal relay location. The simulation results reveal important insights into designing a relaying network with high system capacity.     

分集接收技术在海上升空通信中继系统中的应用

海上升空通信中继系统是解决海上广域无线宽带通信的重要手段,但其性能易受海面波动带来的多径衰落影响。为了有效提升中继系统接收信号质量,提出了一种多天线分集接收方法,通过现场可编程门阵列(Field Programmable Gate Array, FPGA)实现相应的接收处理。仿真分析及实验室测试表明,所提出的四天线分集接收技术能够带来近6 dB的合成增益。经海上对比试验验证,采用所提出的多天线分集接收技术的升空通信中继系统,其数据接收完整性提升了10%～20%,系统性能显著改善。     

无线网络覆盖方案仿真实验设计与实现

本文以无线信号传播模型为基础,以实现对某区域内无线网络覆盖为目标,设计了覆盖半径随无线参数变化的基础实验、基于三种经典启发式算法的无线网络覆盖方案提高实验和基于改进算法拓展创新实验,形成了一个完整的系统性实验。通过实验教学学生可以了解到无线通信信号传播和网络覆盖理论知识,并能够掌握无线网络覆盖方案设计方法,是一个理论与实践相结合、有层次、有创新的综合设计性实验。     

北斗卫星导航接收机抗窄带干扰技术研究

卫星导航系统主要通过人造卫星作为信号转发的中继站,通过上下行链路建立地球站间的无线通信,可实现大容量、远距离、高覆盖面、低延时的信息传输,而且导航系统存在接收电平低、接收机灵敏度高、接收信号比较微弱、导航信号在同一频率发射、调制、信噪比极低、下行链路容易干扰等问题。系统分析了北斗卫星导航接收机抗干扰主要应用技术;介绍了接收机主要干扰类型;提出了时空二维联合处理(STAP)抗窄带干扰技术模型及最小均方误差滤波器(MMSE)算法;通过仿真研究,该方法抑制窄带干扰效果较好。     

Contract design for relay incentive mechanism under dual asymmetric information in cooperative networks

Cooperative relay network can effectively improve the wireless spectrum efficiency and extend the wireless network coverage. However, due to the selfish characteristics of wireless nodes, spontaneous cooperation among nodes is challenged. Moreover, wireless nodes may acquire the different network information with the various nodes’ location and mobility, channels’ conditions and other factors, which results in information asymmetry between the source and relay nodes. In this paper, the incentive issue between the relay nodes’ cooperative service and the source’s relay selection is investigated under the asymmetric information scenarios. By modeling cooperative communication as a labour market, a contract-theoretic model for relay incentive is proposed to achieve the twin objectives of ability-discrimination and effort-incentive. Considering the feature of asymmetric information, the static and dynamic information of the relay nodes are systematically discussed. To effectively incentivize the potential relay nodes to participate in cooperative communication, the optimization problems are formulated to maximize the source’s utility under the multiple information scenarios. A sequential optimization algorithm is proposed to obtain the optimal wage-bonus strategy with the low computational complexity under the dual asymmetric information scenario. Simulation results show that the optimal contract design scheme is effective in improving the performance of cooperative communication.     

无人机辅助空地协同无定形组网仿真评估

现有无线通信网络正在从"以基站为中心的" 蜂窝化组网向"以用户为中心的" 无定形组网演进.然而,现有的无定形组网技术其组网的灵活性受限于地面基站的部署位置.针对现有无定形组网技术灵活性受限的问题,提出了空地协同无定形组网技术.通过采用以用户的需求驱动无人机中继悬停部署实现地理空间层面无定形组网,采用"控制覆盖与业务覆盖...