WLAN Mesh技术城域覆盖探讨

介绍了无线Mesh网络技术发展概况及技术特征,基于实际工程经验,对WLAN Mesh技术的工程应用进行了探讨,以期望助力于国内"无线城市"工程建设。     

5G超密集组网关键技术与组网架构探讨

5G超密集组网是建设绿色、高效、灵活部署5G网络的关键技术。也是应对未来1000倍流量增长的必然要求。随着大量低功率站点部署,虽然提升了系统容量,但面临因站间距太小带来了干扰和频繁切换问题,影响用户体验,以及大量低功率站点部署需要消耗大量的传输资源。本文重点讨论了解决这三个问题的关键技术：虚拟小区技术、双连接技术、CoMP干扰协调技术、无线回传技术。探讨了5G超密集组网架构实现。     

Asymmetrical Doherty power architecture with an integrated driver stage in the auxiliary branch

This contribution presents the analysis, design and characterization of a high gain Doherty power amplifier implementing an integrated Driver stage in the Auxiliary branch. Guidelines and design equations are demonstrated, fulfilling the full integration of the whole new architecture. The development of a microwave monolithic integrated circuit prototype based on TriQuint GaN technology for 7 GHz applications is reported. 10.5 dB of Gain, 38.1 dBm of saturated output power and 42% of efficiency at 7 dB of output back‐off have been demonstrated by experimental results. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:498–507, 2014.     

Multipath multihop mmWave backhaul in ultra-dense small-cell network

Ultra-Dense Network (UDN) is considered to be the key enabler for realizing capacity goals set by 5G. The major concern in UDN deployment is the backhaul network, which should be scalable, cost-effective, and have sufficient capacity to support massive small cell traffic. Otherwise, the backhaul can become the bottleneck of the network. In this paper, we propose a wireless backhaul solution for UDN deployment by considering MultiPath-MultiHop (MPMH) backhaul architecture in mmWave frequency band. In addition, we propose a distributed routing scheme to forward the backhaul traffic over the multihop network. Backhaul capacity and line-of-sight probability of the proposed backhaul architecture for various picocell densities were compared with direct, multiple-association, and multihop backhaul schemes under interference limited scenarios in outdoor and indoor small cell deployments. The simulation results indicate that the MPMH mmWave backhaul is the most cost-effective and scalable solution for UDN deployment.     

谐波减速器的传动精度分析

以某舵机齿啮式谐波齿轮减速器为研究对象,分析了影响其传动精度的误差源,在忽略伞齿轮副的高频误差和齿啮式输出误差的前提下,对谐波齿轮副的传动误差进行了理论计算,用谐波传动精度动态检测仪测量了整个减速器的传动链误差.结果表明计算值与测得值基本吻合,两者误差在10％以内,说明假设前提条件成立,为设计从理论上提高谐波减速器的传动精度提供本参考,具有实际应用价值。     

求解模糊需求可回程取货车辆路径问题的改进人工鱼群算法

模糊需求可回程取货车辆路径问题是运筹学领域研究的一个热点问题。文中构建该问题的数学模型,并提出一种改进的人工鱼群算法。将人工鱼群算法仿生学原理和决策者主观偏好进行有效结合,重构人工鱼群算法的寻优公式,通过动态调整人工鱼移动步长、视野范围和邻域值等方法提高寻优能力。仿真实验结果证实该算法的有效性和优越性。     

End-to-end performance aware association mechanism for wireless municipal mesh networks

In a wireless municipal mesh (muni mesh) network, a client station (STA) needs to associate with a mesh access point (MAP) for network access. Previous association mechanisms assume high-speed backhaul and only the access link being the bottleneck. This assumption holds for most WLANs, but in wireless mesh networks traffic could be bottlenecked either by the access link or by the bandwidth-limited wireless backhaul. In this paper, we propose a new joint MAP association mechanism for wireless muni mesh networks to improve STA’s end-to-end communication performance. A STA makes its association decision by jointly considering the quality of the access link between the STA and the associated MAP as well as the cost of the multi-hop path from the associated MAP to the Internet gateway. In addition, we design two new metrics, Contention Aware Expected Transmission Time (CAETT) and Load Aware Expected Transmission Time (LAETT), to measure the access link quality. The main strength of CAETT is incorporating the impact of 802.11 MAC layer contentions on the bandwidth sharing of multi-rate stations. LAETT further captures the real traffic load on the shared medium. In order to reduce the association delay, we use an analytical model to derive a hybrid measurement/estimation method to enable a station to quickly determine the cost of CAETT and LAETT. We conduct extensive simulations to evaluate the performance of the proposed joint MAP association mechanism. Especially within the joint association framework, we investigate the impact of various combinations of access link metrics (RSSI, PB, CAETT, LAETT) and backhaul routing metrics (hopcount, ETT, RALA) on the system performance. We show that the joint association mechanism can significantly improve the network performance in terms of throughput and delay by up to 100%. In particular, the joint association mechanism with LAETT as the access link metric and RALA as the routing metric outperforms other schemes and metrics.     

毫米波在5G中的应用

5G性能相比4G,容量更大、速率更快、连接数量更多,高性能的实现需要连续大带宽频谱的支持,目前分配的中低频段满足不了5G需求.毫米波利用其丰富的频谱资源,能很好地满足5G连续大带宽需求.本文对毫米波在无线通信中的优劣势进行分析,并介绍毫米波在5G中的应用场景,最后通过测试结论证明通过使用毫米波提高系统速率和容量的可行性...     

LTE业务对回传网络需求特点的分析

在阐述LTE网络架构的基础上,深入分析了LTE回传业务IP化、带宽、流量、时延、同步等特点,提出了LTE业务所需的回传网络模型,为组织回传和前传网络提供了有益参考。     

WCDMA数据业务回传承载网络研究

研究WCDMA承载网络现状及演进特点,分析当前MSTP承载遇到的困难,提出不同阶段的网络演进方案。该方案可充分利用IP网络资源,降低汇聚层建设投资,简化网络规划和配置,提高维护便利性。