FD载波射频互助提升TD-LTE小区上行覆盖能力

TD-LTE网络存在上行覆盖受限的问题,本文探索通过FD载波射频互助的方式,基于现网D/F双层网的组网结构,将D频段小区的接收通道用于F频段小区的上行接收,实现F频段小区的16通道接收,进而提升F频段小区的上行覆盖能力.     

TD-LTE网络F+D异频混合组网规划研究

针对TD-LTE建网初期现网结构不尽合理造成的网络问题,提出了以F频段为主,D频段局部异频的规划方式。以某省会城市TD-LTE网络规划为例,通过对全F组网、站址降高、F+D混合组网仿真分析,验证了F+D混合组网方案对网络性能提升的可行性。     

分时长期演进系统F频段和D频段组网选择

TD-LTE（分时长期演进）系统建设面临着频谱资源受限,新旧网络并存,多运营商并存的诸多问题,灵活地进行F和D频段网络部署,策略地分阶段、按不同侧重点来进行混合部署方可有效的化解这些难题.从理论分析、网络规划建设出发,讨论TD-LTE系统采用F和D频段组网的优劣并进行对比分析,给出优选方案.建议采用F加D多频段混合组网的方式,即初期采用F频段快速建网做基础覆盖,后续采用D频段做容量补充.     

TD-LTEF频段和D频段组网对比分析的理论研究

主要规定了面向建设运营的TD-LTE测试与攻关,研究TD-LTE系统F频段与D频段组网覆盖以及网络性能对比的内容。     

TD-LTE F/D协同组网的频率优先级策略探讨

数据业务的爆发性增长,对LTE时代网络的覆盖和容量提出更高的要求。为提升LTE(长期演进)无线网络的竞争力、用户业务需求,未来室外网络部署的演进方向一定是F+D多频段网络。文章根据D频段、F频段的特点,从TD-LTE小区重选和切换的原理出发,分析F/D协同组网下不同的频率优先级策略,并给出参数配置建议。同时,针对未来的部署策略,探讨载波聚合下F/D混合组网方案。     

TD-LTE系统共址跨厂家双层网负荷均衡剖析与优化方法

随着TD-LTE双层网的开通,网络复杂度增加,在当前D频段网络已基本形成连续覆盖的情况下,充分利用F频段的无线传播性能差异,可以有效弥补D频段信号对现网深度覆盖不足的短板,才能充分发挥双层网优势,提升覆盖、质量及容量,保证4G驻留.本文通过分析、实施及总结出共址跨厂家双层网负荷均衡的调整方法可供D+F双层网部署和精细优化提供参考.     

排除F频段组网障碍 提升LTE整体性能

排除F频段干扰问题是TD-LTE在F频段建网需要解决的首要问题,仅通过软件升级方式即可有效提升现网TD设备在F频段的抗干扰性能。目前,中移动已应用F频段在广深杭三个城市进行TD-LTE扩大规模试验的组网建设。相比D频段,F频段无线传播损耗大大减小,而且应用F频段组网可在原有TD-SCDMA网络基础上,平滑演进升级支持TD-LTE。采用F频段建网可大幅节约建网成本,     

TD-LTE D/F双层网策略

随着用户的快速增长和网络的不断发展演进,目前中国移动单频段网络已经不足以支撑容量和业务的增长以及用户感知的稳定,F+D的多频段组网必将成为趋势。为了充分利用F+D多频点组网的优势,解决热点区域容量以及部分深度覆盖问题,文章从覆盖和负荷两个方面着手,对重选、切换、负载均衡策略及互操作参数进行了深入研究,经过实际测试验证,按照文章策略的组网方式对分担网络流量,改善深度覆盖有明显的效果。     

TD-LTE(D+F)双层组网策略研究

从D/F频段的性能特点出发,针对目前D频段连续覆盖情况下F频段应用的一系列问题开展研究,并基于现网研究和测试结果总结出LTE网络中D/F频段间的协同策略、应用方法和优化方法。     

TD-LTE深度覆盖方案

TD-LTE网络的技术特性和业务定位对网络深度覆盖提出了更高的要求,与此同时,高频段的频率资源、建筑物密集的商务区等目标覆盖场景又极大增加了深度覆盖的难度.本文基于TD-LTE部署频段的覆盖能力分析,提出了异构网组网是解决TD-LTE的深度覆盖的有效手段,并论述了异构网组网的主要技术方案.     

一种基于VoLTE语音质量的异频切换方法研究

中国移动用于室外广覆盖的TD-LTE网络主要有F频段和D频段,两个频段之间的切换主要是基于覆盖的异频切换,切换前用户的RSRP和SINR会比较差,切换后会获得明显提升。前期TD-LTE网络主要承载数据业务,目前VoLTE语音业务发展迅猛,原有基于RSRP的异频切换方式已不适应语音异频切换。为了提升4G客户VoLTE语音业务感知,本文提出了一种基于VoLTE语音质量的异频切换方法。     

TD—LTEF频段和D频段间的协同策略

频谱资源是运营商竞争的基础;在移动互联网时代,用户需求将爆炸式地快速增长,为提升自身LTEN络的竞争力、提供尽可能高的带宽,未来F频段和D频段将在同一本地网上同时部署。本文全面分析了两频段间的协同策略、分场景给出了配置建议;同时分析了两种技术实现方案,并给出了工程应用建议。     

中国移动在A频段5G部署策略研究

首先分析了中国移动可以使用的频率资源,建议随着3G用户的大幅减少,采用SUL方式在A频段上部署5G网络,以增加上行峰值速率和降低空中接口时延,然后给出了SUL载波和NUL载波的调度方式以及SUL参数的配置原则和建议,最后给出了A频段、D频段和3.5 GHz频段的峰值速率,采用SUL方式,A频段和D频段的上行峰值速率可以...     

TDD-LTE三载波聚合性能分析研究

数据业务的爆发式增长,更宽频谱的需求成为了影响从LTE向LTE-Advanced演进的最重要因素。为此河南公司开展了三载波聚合的性能测试研究,包括基于2.6GHz的D频段、F+D频段的载波聚合,以及室内的E频段,速率已经达到220Mbps。TDD-LTE的三载波聚合技术在将多个载波聚合成一个更宽的频谱的同时会造成不必要的重传,并且具有较大的HARQ反馈时延,制约了载波聚合技术对于用户感知的进一步改善。因此,本文将主要以现网分析的方式,讨论如何解决LTE-Advanced系统中TDD-LTE三载波聚合技术所面临的现网的问题。实测结果表明三载波聚合技术后不仅大幅度提升了传输速率,还能有效改善网络质量,提升吞吐量,使网络负载更加均衡,尤其是在负载较重的时候效果会更明显。     

4.9 GHz异帧干扰问题研究

相对2.6 GHz频段,4.9 GHz频段可以通过灵活的帧结构配置满足上行大带宽的行业应用需求,但异帧结构组网可能导致基站和终端之间存在交叉时隙干扰,因此研究4.9 GHz的异帧干扰问题是非常必要的.基于3D-UMa传播模型,研究了4.9 GHz频段1D:3U:1S和5D:3U:2S帧结构配置下的交叉时隙干扰问题,并结...     

Energy‐spectrum‐efficient three‐tier heterogeneous networks with D2D harvesting energy and uplink coverage analysis

To guard the communication quality of cell edge users (CEUs) and simultaneously improve the energy‐spectrum efficiency, a novel 3‐tier heterogeneous network (HetNet) model is proposed, which consists of macro cells, femtocells, and device‐to‐device (D2D) networks. Specially, with a predefined cell split factor R , the macro cell users are split into as cell center users (CCUs) and CEUs, respectively. Correspondingly, the total available spectrum band consisting of N channels is divided into CCU band and CEU band with a given coefficient p_m. The CCU band containing p_mN subchannels is shared by CCUs and femtocell users (FUs), and the CEU band containing (1 ? p_m) N subchannels is shared by D2D users and CEUs. The perfect network synchronization is assumed, and a communication round consists of downlink transmission and uplink transmission phases. The battery‐free D2D terminals harvest energy from the ambient radio frequency interference in the downlink transmission phase based on inverse power control scheme and communicate in the uplink transmission phase only when they harvest enough energy to perform channel inversion toward the receiver. For such 3‐tier HetNets, by modeling the network elements as independent Poisson point processes (PPPs) and using stochastic geometry method, we first investigate the sufficiency probability that a D2D transmitter harvests enough energy to establish a communication link. Then, by combining sufficiency probability and channel access probability, the thinned independent PPPs for the locations of CCUs, CEUs, FUs, and D2D users are modeled. Based on these thinned PPP models, we perform a comprehensive investigation on the coverage probabilities of CCU, CEU, and FU uplinks as well as the D2D transmission. The simulated and numerical results show that using the presented cell split strategy enhances the performance of CCUs and CEUs because of the decrease of interference. The presented comparison analysis displays that the effect of D2D networks on the macro cell or the whole HetNets is limited and can be omitted. Therefore, the energy and spectrum efficiencies of networks are enhanced, simultaneously. At the same time, our results indicate that by using our derivations, we can perform the optimal design of the HetNets.     

Power allocation and relay selection for network-coded D2D communication underlay heterogeneous cellular networks

Underlay device-to-device (D2D) communication is an attractive technology enabling nearby cellular users to communicate with each other directly in order to increase data rate and spectral efficiency. The current cellular heterogeneous networks consist of macrocell base stations and small cell base stations with different transmit powers and coverage areas. Femtocell is the most popular small cell which is expected to be utilized in dense and ultra-dense scenarios in the future. Network coding in relay-assisted multi-hop communications improves achievable transmission rate and coverage of D2D communications. In this paper, two-hop random linear network coding network in cooperative D2D communication (RLNC-CDC) is considered. We propose to use femtocell base station (FBS) as a relay. We assume that the D2D pair and relay operate in the frequency band which is allocated to femtocell network. Therefore, there would be interference from the relay node and the D2D communication on the femtocell network users. To reduce the interference, the sum of transmit powers of the D2D pair and selected relay FBS should be minimized in a way that the highest transmission rate for the D2D pair is achieved. The constraints on the bounds of transmit powers of the D2D and relay node as well as the minimum required transmission rate for D2D communication are considered and the optimum solution is obtained. Simulation results indicate that the proposed RLNC-CDC achieves higher data rate and smaller outage probability than the direct D2D transmission.     

4.9 GHz异帧隔离间距研究

4.9 GHz频段在面向大容量的热点场景时具有独特优势,通过使用4.9 GHz的1D:3U:1S帧结构配置能够有效提升网络的上行能力.针对4.9 GHz的1D:3U:1S和5D:3U:2S两种帧结构同时部署引入交叉时隙干扰的问题,研究了不同场景下异帧部署4.9 GHz站点的最佳隔离间距.本文首先根据传播模型推算出4.9...     

基于遗传算法的多限制路由解决方案

随着互联网用户和流量的迅速增长,网络资源不足及网络拥塞问题日益严重。而各种新的多媒体业务的出现又对网络的服务质量提出了新的要求。为此文中以在满足带宽、时延的基础上,将资源消耗和负载均衡分布作为优化目标,希望在消耗较少网络资源的同时,使负载尽量分布在有宽裕空闲资源的链路上,从而利用遗传算法的原理提出一种优化网络的方法并通过仿真证实了其有效性。     

Interference Analysis in an Urban Mesh Network Operating in the 60‐GHz Band

Because of their exclusive features, millimeter wave directive mesh networks can be considered for small cell backhaul support in urban environments. For this purpose, a network of closely spaced stations has been considered with very directive line‐of‐sight links operating in the 60‐GHz band. An attempt is made to evaluate channel response and interference behavior in such a network, taking into account the effect of building blockage. A simple grid of building blocks is considered as the propagation environment, and wave propagation is simulated using 2.5‐dimensional (2.5D) ray tracing (2D with ground effect) to calculate the received signal at different nodes in the network. The results are compared with free space predictions and used to evaluate interference at all nodes in the channel and describe certain characteristics of links, such as the delay profile and the correlation length.