基于MR弱覆盖提升TD-LTE终端驻留比的方法

LTE驻留比作为LTE网络优化的重要参数，移动在多网并存的情况下，令更多的用户体验到更快更好的网络是运营商的奋斗目标。本文通过调整弱覆盖参数的方法来提高LTE驻留比及MR覆盖率，从而让更多的用户驻留在4G上，实验证明该方法对LTE驻留比的提升有一定作用。     

LTE网络体育场馆覆盖方案研究

体育场场馆形状开阔,在不举办活动时,靠室外LTE基站就能获得较好的覆盖,但是在举办各种大型活动时,由于用户数爆发性增长,容易导致LTE出现网络拥塞,本体育场覆盖研究方案,先从体育场内的高峰期容量需求进行分析,结合体育场结构特点,再针对性地提出相应的有源室分覆盖解决方案。     

A new C-RAN architecture based on RF signal soft-switching

Coordinated multi-point (CoMP) is known to be one of the key technologies for long-term evolution (LTE)-advanced systems. CoMP technology can improve system capacity and the quality of wireless communication services for users in LTE networks. However, in practice, the actual performance of CoMP technology is limited by the switching capacity of the backhaul network among distributed base stations as well as its latencies. In this paper, we propose a new cloud radio access network architecture based on RF signal soft-switching to solve this problem. Furthermore, we introduce a narrow-band parallel processing technique on a common public radio interface in downlink and uplink to reduce the volume of data as well as the latencies in the transmission process among base band units and remote radio units. By combining theoretical analysis with computer simulations, we show that the technique is valid both for downlink and uplink, i.e., it does not degrade the performance of downlink and uplink propagation between BBU pool and user equipments. Moreover, the computational time of the narrow-band parallel processing technique is less than that of the standard technique.     

高铁TD-LTE双层网组网规划优化研究

随着4G移动数据业务应用迅速增长,无线网络尤其是热点区域网络负荷已进一步抬升.聚焦五高一地,高铁场景方面在继续做好现有专网基础覆盖的同时,需重点针对高铁专网的网络性能和上网体验持续加强精细优化,对原有单层网覆盖开展容量优化,以此来保障高铁用户的极速4G体验.     

物理层网络编码在数据会聚无线自组织网络中的容量增益研究

为研究物理层网络编码.(Physical-layer Network Coding,PNC).方案在数据汇聚无线自组织网络中相对于传统方案能够获得的容量增益,该文通过稀疏割容量分析推导得到PNC方案平均每节点信息传输速率的上界和下界。与传统路由方案及传统网络编码方案相比,在数据汇聚无线自组织网络中应用PNC方案能够提升网络容量的数量级。     

ONU buffer reduction for power efficiency in Passive Optical Networks

Power efficiency will be one of the primary factors dictating the choice of future network deployments. Passive Optical Networks (PONs) in general consume less power and are well positioned to be the technology of choice for future access networks. In a PON, the Optical Network Units (ONUs), that provide the interface between the end user and the Optical Line Terminal (OLT), consume a substantial amount of power. Typically, 2 MB or more buffer capacity is used in an ONU for holding upstream packets. This consumes around 1.29 W of leakage power when idle. In the current work, we show the relationship between buffer capacity and leakage power consumption. This motivated us to propose buffer reduction as a strategy to reduce power consumption of an ONU. We propose three schemes viz. Zero Buffers (ZBs), Node Proportional Buffers (NBs) and Rate Proportional Buffers (RBs). They impose aggressive buffer capacity restrictions on the ONU to reduce power consumption. Having said that, these schemes cannot be realized without modifications to the basic network operation. We propose mechanisms required to support the buffer reduction schemes. Through simulations we explore the relationship between power consumption and network performance. We also present the comparison of the proposed schemes in terms of network performance with different network loads. Simulation results indicate that despite buffer size reduction, an acceptable level of application level performance can be achieved. We show that buffer reduction as a strategy is viable and can cut down more than 90% of leakage power consumed by packet buffers at the ONU.     

卫星信关站硬件平台的实现方案

基于LTE的星地融合宽带通信网兼有卫星网和地面网的互补优势,能实现大范围覆盖,信关站是连接卫星网与地面网络的桥梁。分析信关站硬件平台的功能与性能需求,依据网络处理器、专业多核处理器和PowerPC处理器等3种硬件平台,提出适合卫星信关站硬件平台的3种方案,根据不同的应用可选择适合的方案。     

智慧城市时代室内LTE部署方案浅析

随着智慧城市时代的到来,无线网络建设需要2G/3G/WLAN和LTE等多种网络制式协同组网,共同为智慧城市提供通信服务。文章结合实际工程调研,提出室内覆盖工程中LTE的建设原则,对不同的LTE室内分布系统建设方案进行对比分析,并结合某省联通实际网络建设情况,提出LTE室分的实施方案,对后续的网络建设提供参考依据。     

LTE室内覆盖不同建设方式探讨

LTE室内覆盖建设是运营商4G建设的难点,也是用户当前投诉的热点。本文对室内覆盖建设中分布式天线系统、光纤分布系统、小基站等不同建设方式进行了分析和对比,总结了各个建设方式的特点,并对适用的建设场景给出了建议。     

SBT (Sense Before Transmit) Based LTE Licenced Assisted Access for 5 GHz Unlicensed Spectrum

Utilization of unlicensed spectrum under licensed assisted access ensuring fair co-existence with Wi-Fi networks is a good solution to address immense usage of mobile data. Radio communication operation of LTE in unlicensed frequency band is referred as LTE-unlicensed (LTE-U) or LTE-licensed assisted access. In this paper, we consider a HGNW in which coverage area of Wireless-Fidelity (Wi-Fi)’s Access Point is integrated within the LTE-U small base station’s cellular network coverage area. To overcome the disadvantages of existing LTE-U technics like carrier sense adaptive transmission and listen before talk, we proposed a new methodology i.e., sense before transmit in this paper by adopting a transmit power control mechanisms using reciprocity theorem based on the channel state information to assign the secondary carriers in the uplink as well as in the downlink directions in the unlicensed spectrum to carry the traffic. In our proposal, LTE-U users are allowed to use the unlicensed spectrum provided that the interference produced at Wi-Fi users due to LTE-U activities is remained below a certain threshold. We evaluated the performance of proposed network model in terms of outage probability and achievable throughputs.

     

Leveraging multiuser diversity for adaptive hybrid satellite‐LTE downlink scheduler (H‐MUDoS) in emerging 5G‐satellite network

In order to achieve ubiquitous coverage and service continuity in future 5G network, satellite‐based access is the best solution to complement the terrestrial LTE‐A. In light of this, we introduce a channel‐aware hybrid scheduling technique on the basis of satellite‐LTE spectrum sharing. According to the user‐experienced channel, base stations (eNodeB) and the satellite will work cooperatively. The eNodeB mainly provides service in urban area for high density population. Meanwhile, the satellite will perform either offloading, providing service for under‐served users, or extra coverage for users in rural and remote areas having no coverage of eNodeB. Leveraging the multiuser diversity, we implement a new metrics computation method for hybrid satellite‐LTE downlink scheduler (H‐MUDoS). Compared with other existing schedulers, simulation results clearly demonstrate the high performance of H‐MUDoS in terms of spectral efficiency in addition to improvement of the quality‐of‐service requirements and capacity maximization.     

A review of mobility management entity in LTE networks: Power consumption and signaling overhead

Mobility management (MM) in Long‐Term Evolution (LTE) networks is a vital process to keep an individual User Equipment (UE) connected while moving within the network coverage area. MM Entity (MME) is the LTE component responsible for tracking and paging procedures and controlling the corresponding signaling between the UE and its serving cell, which is necessary for data‐packet exchange. Because of the massive increase in the density of mobile UEs, MME is burdened by the high volume signaling load, especially because most of that load comes from Tracking Area Update (TAU) and Paging messages, which are essential to exchange UE‐specific information with the network. To achieve cost‐efficient resource provisioning, many solutions have been proposed for TAU and Paging management to optimize not only UE experience (ie, battery power consumption) but also network resources (ie, bandwidth). In this paper, we discuss various solution schemes for TAU and Paging in terms of complexity, latency, and computation costs. Also, this review discusses the adverse effects of these solutions on the LTE Key Performance Indicators (KPIs). Furthermore, we present a new trend of MM solutions in LTE networks, called software‐defined network (SDN) and software‐defined virtualization (SDNV). To this end, we examine the existing schemes and challenges in the literature toward next‐generation wireless networks (eg, 5G, Internet‐of‐Things [IoT], and machine to machine [M2M] communications), and we describe user mobility models that are used to analyze the network performance.     

特殊场景的LTE覆盖技术

文章首先介绍了 LTE异构网和 LTE立体组网技术,在此基础上,重点研究高铁和密集城区的 LTE覆盖技术。讨论了如何应对高铁 LTE覆盖的多普勒频移效应问题,并给出了高铁沿线覆盖和隧道两种环境下的组网方式建议。最后,探讨了如何采用 LTE异构网和立体组网技术,通过合理的网络布局来解决密集城区的容量和深度覆盖问题。     

QoS Guaranteed Resource Allocation Scheme for Cognitive Femtocells in LTE Heterogeneous Networks with Universal Frequency Reuse

In this paper, we propose a novel resource allocation scheme for co-channel interference avoidance in LTE heterogeneous networks with universal spectrum reuse where both macro users (MUs) and cognitive femto base stations (FBSs) within the same macrocell coverage can dynamically reuse whole spectrum. Specifically, resource blocks (RBs) are shared between cognitive FBSs in underlay mode while the resource sharing among FBSs and MUs is in overlay mode. The macrocell is divided into inner and outer regions with the inner region further divided into three sectors. The proposed scheme addresses co-channel interference (CCI) by employing fractional frequency reuse (FFR) for RB allocation in the outer region of the macrocell and increase the distance of users that reuse the same RB within the macrocell. Part of RBs are allocated to the outer region of the macrocell with a FFR factor of 1/3, while the remaining RBs are dynamically allocated to each sector in the inner region of macrocell based on MUs demand to efficiently utilize the available spectrum. A basic macro base station (MBS) assistance is required by the FBS in selection of suitable RB to avoid interference with MU in each sector. With the proposed solution, both macro and femto users can dynamically access the whole spectrum while having minimum bandwidth guarantee even under fully congested scenarios. Moreover, the proposed scheme practically eliminates the cross-tier interference and the CCI problem in heterogeneous network reduces to inter-femtocell interference. The throughput and outage performances of the proposed scheme are validated through extensive simulations under LTE network parameters. Simulation results show that the proposed scheme achieves a performance gain of more than 1.5 dB in terms of SINRs of both macro user and femto user compared to traditional cognitive and non-cognitive schemes without bandwidth guarantee for femtocells.     

Research on LTE Network Coverage Planning

When deploying an LTE network,coverage planning is critical to reduce construction costs and ensure network quality.This paper considers actual network planning requirements and combines theory with simulation analysis to study LTE wireless access link and network characteristics.A theory for LTE cellular coverage planning and application methods is proposed that lays the basic foundation for LTE cellular networks.     

LTE语数分层策略研究及优化效果

随着LTE网络的不断发展,D+F多层网覆盖逐渐成熟,根据VoLTE业务的需求特点,将其承载于固定的频率层,实现LTE语音与数据分层。本文从LTE多层网各自优势出发,结合VoLTE业务强覆盖低速率的需求,将VoLTE业务态用户分离至F2频率层,达到优化VoLTE网络覆盖和提升用户感知的目的。     

利用用户移动提高WiFi业务分担能力的用户激励机制研究

WiFi网络可以分担蜂窝网络的通信业务压力,缓解其拥塞状况。然而,WiFi网络的业务分担只能在其覆盖范围内进行。由于用户具有移动性,如果通过提供一些奖励引导WiFi网络覆盖范围之外的用户延迟其在蜂窝网络中的业务、直至其进入WiFi覆盖区再接受服务,WiFi网络的业务分担能力将得到显著提升。该文探讨了运营商通过激励机制鼓励用户延迟其蜂窝网络业务转而接入WiFi网络的过程,并将其建模为两阶段斯塔克博格(Stackelberg)博弈。在该博弈中,运营商期望采取最优的奖励方案,能够兼顾蜂窝网络拥塞和付出的用户奖励。该文推导出了运营商的最优奖励方案。数值结果表明,所提激励机制可以有效降低包括蜂窝网络拥塞代价和奖励用户代价在内的运营商总代价。     

基于WLAN设施实现居民区LTE深度覆盖的方案研究

通过对国内某运营商的LTE网络数据进行分析研究,发现LTE深度覆盖问题主要集中在住宅小区.根据对WLAN建设情况的调查,大量住宅小区已部署WLAN网络,从而使利旧并改造WLAN基础设施,快速、低成本、差异化的解决LTE深度覆盖方案具备可行性.     

中国电信3G网络承载能力提升探索

针对中国电信3G网络用户持续快速增加,已无多余频点资源用于扩容的现状,从不增加额外频点及硬件资源的角度,仅研究参数设置,提出了一套提升3G网络承载能力的参数设置方法。通过网优手段在一定程度挖掘3G网络潜力,为LTE网络提供了建设缓冲期。     

Dual bus MAN's with multiple-priority traffic

A protocol with strictly preemptive priorities that does not admit low-priority traffic if the load from high-priority traffic exceeds the capacity of the transmission channel in a MAN is presented. The protocol guarantees fairness for transmissions at the highest priority level. By introducing a general characterization of bandwidth allocation schemes for dual bus networks, existing priority mechanisms can be categorized according to the provided quality of service. The unique existence of a bandwidth allocation scheme for multiple priority traffic is shown with a full utilization of the channel capacity, with a fair distribution of bandwidth respective to traffic from a particular priority level, and with preemptive priorities. The performance of the presented protocol is compared to existing proposals for multiple priority mechanisms. It is shown that adopting the new protocol results in shorter access delays for high-priority transmissions. The protocol allows the stations of the network to react quickly to load changes. It is shown that the effectiveness of the priority scheme, compared to priority schemes using the bandwidth-balancing mechanism, is less dependent on increasing the transmission speed of the network