LTE-A载波聚合下的载波切换分析

多载波聚合技术是LTE-A(LTE-advanced)系统的一个关键技术,它能解决LTE-A系统对带宽资源的需求.由于不同频带的信号传输功率、覆盖范围不尽相同,使得终端在小区间的切换成为难点.本文在LTE切换流程的基础上分析了LTE-A载波聚合环境下的载波切换场景、小区内及小区间的载波切换流程,为了减少多载波切换的失败率,提出了同时向多个符合条件的相邻小区发出切换请求并选择其中最佳小区进行切换的改进思路,同时针对多目标eNB切换方式设计了两种多载波切换方法.     

CDMA2000多载波交界规划研究

文章讨论了在CDMA2000系统中。手机在多载波交界区域由于无线规划不合理引起的瞬间脱网、被叫不良等常见的缺陷，并根据CDMA2000协议中相关空闲切换操作流程分析了原因，随后总结多载波交界建网的若干要求。最后提出了CDMA2000下多载波交界区域规划经验原则。     

一种基于载波聚合的切换方法的设计方案

载波聚合技术是LTE-A中的关键技术,与LTE系统中基站仅支持单一的载波切换相比,LTE-A中需要支持多载波的功能,因此需要一种可以支持多载波切换的方法。从RRC协议的角度出发,提出一种支持切换方案,通过在切换过程中释放源辅小区,并在切换完成后根据情况重新建立辅小区的方法,实现了带有载波聚合功能的切换,并且给出载波聚合下切换详细设计流程。最后在实际环境中对此流程进行验证,给出测试结果,实现了带有载波聚合功能的切换。     

浅谈载波池技术在实际中的应用

载波池技术作为一种优化无线网络载波资源手段，可针对不同小区的话务高峰在时间上的差异，来实现小区间载波资源的快速切换．从而确保高话务量区域的通信畅通。文中介绍了载波池技术的基本工作原理．并对载波池技术的应用前景、优点、应用时应注意的问题进行了探讨。     

CDMA1X网络双载波规划优化策略及实践

文章从CDMA1X终端空闲待机模式、接八负荷分担模式、双载波边界区域切换机制选择三个方面考虑了双载波规划优化策略：以B城市城区201载波调整优化方案实旌为例，评估了网络质量改善效果，并对双载波规划优化经验作了总结。     

浅析中波发射机的频率合成器设计

当前中波广播发射机的频率合成器一般都采用直接数字频率合成技术(DDS)设计,频率合成器输出的射频信号用作中波发射机工作的RF载波,同时调幅立体声广播和多部发射机并机工作时由DDS频率合成器提供激励射频载波的I/O接口,同时它还具有保护切换功能,当发生驻波比故障时进行保护性切换.     

面向5G基于C-RAN宏微协作的极简数据载波设计

提出了一种面向5G密集网络部署的极简数据载波设计。极简数据载波是在C-RAN架构下的一种微蜂窝数据载波,主要用于数据承载,支持无公共信道开销、极少或者没有控制信道开销,能够有效降低密集数据载波之间信令的干扰,较大幅度提高能效,并由于设计简单有利于降低数据载波的成本。重新设计了传统数据载波的信令,并重新设计宏基站和微基站的接口和交互流程。重点解决了3个问题:微基站载波的发现和选择、用户同宏微载波的同步接入、宏微和微微载波间的测量切换。仿真结果表明,在相对理想的回传支持下,能较大幅度提升系统的切换性能、吞吐量和能效。     

cdma1x网络双载波规划优化策略及实践

从cdma 1x终端空闲待机模式、接入负荷分担模式、双载波边界区域切换机制选择角度考虑了双载波规划优化策略;并以B城市城区201载波调整优化方案实施为例,评估了网络质量改善效果,并总结推广双载波规划优化经验.     

WCDMA多载波部署及优化策略研究

通过对多载波部署策略的分析,结合中国联通实际情况,重点分析了同频段多载波部署方案,总结了多载波小区重选和切换的性能指标以及优化方法,通过在网络现场的优化经验,总结出适合不同场景的参数模板进行推广。     

LTE-Advanced中继系统基于辅助载波的协作切换算法

切换是移动性管理的重要组成部分.在LTE-Advanced系统中,由于中继、载波聚合等新技术的引入,给系统的切换机制提出了更高的要求和挑战.通过对传统LTE-Advanced系统和LTE-Advanced中继系统切换过程的分析,提出了LTE-Advanced中继系统基于辅助载波的协作切换算法.该算法利用低频载波传播范围广、高频载波资源相对较多的优势,并结合中继技术和载波聚合技术,达到了降低切换中断概率、提高系统吞吐量的目的.     

WCDMA的硬切换技术

WCDMA的切换可以分为软切换(包括更软切换)、硬切换、前向切换以及系统间切换。一个典型的切换过程包括测量控制、测量报告、切换判决和执行切换。详细介绍了WCDMA的硬切换技术、信令流程,以及在现网中的实现。建议设备厂商尽量支持各种硬切换触发方式,使运营商有更多的选择。希望在正式商用时,硬切换不成为影响网络质量的重要因素。     

多载波蜂窝移动通信系统中的多业务切换算法

提出一种用于多载波蜂窝移动通信系统的子信道合并切换算法。采用多维Markov链对子信道合并切换算法进行系统建模分析,得到了呼叫阻塞率、切换阻塞率等关键系统性能参数的解析结果。与切换保护信道算法相比,子信道合并切换算法在对其他类型呼叫性能影响很小的前提下,改善了对带宽要求较高的业务的切换性能。该算法还可以与其他资源预留切换算法相结合,改善其性能。     

基于RSS准则的CDMA软切换越区研究

硬切换技术中移动台在接收新基站信号之前中断与原基站的通信,通信中断的概率非常大。而软切换技术需要先建立与新基站之间的通信,等接收到原基站信号低于门限值时再切断与原基站的通信,故具有很高的可靠性。采用接收到的信号强度准则对软切换建立仿真模型,对两个小区之间的软切换进行了仿真,仿真结果表明,软切换的可靠性高于硬切换,采用软切换技术降低了系统的掉话率,提高了通信质量。然而,软切换也将使系统的复杂度和信道开销有所增加。     

移动因特网半软切换的仿真研究

MobileIP协议中原有的硬切换算法产生的分组丢失和切换时延大大降低了用户的通信质量，半软切换算法是硬切换的改进算法，本文通过仿真比较了Mobile IP协议中硬切换和半软切换对TCP和UDP流量的影响，并进一步研究了影响半软换性能的因素。     

Performance analysis of CDMA cellular networks with channel sub‐rating

This paper presents the analysis of CDMA cellular networks with channel sub‐rating. From users' point of view, our considered scheme gives higher priority to handoff calls over new calls by sub‐rating the existing connections when handoff calls find no idle channels upon their arrivals. Therefore, it is considered that the disadvantage of the soft handoff which needs more channels than the hard handoff is made up for. Handoff calls can also wait in a queue while they are in handoff areas if all channels are sub‐rated in the cell of interest. We mathematically model this scheme by applying queueing theory. Then, we analyse its performance to derive the blocking probabilities of the new and handoff calls, the probability that handoff calls leave the handoff area without getting new channels, the degradation ratio of the voice quality by sub‐rating, mean and coefficient of variation of the waiting time of handoff calls. In numerical results, the analytical results are compared with the simulation ones to validate our analytical approach. Moreover, we compare the sub‐rating scheme with full‐rating one with respect to some characteristic values to show the effect of sub‐rating. Copyright © 2005 John Wiley & Sons, Ltd.     

Comparing soft and hard handoffs

This paper studies the soft-handoff mechanism and compares its performance with hard handoff. Our study indicates that although a handset may potentially consume extra radio links in soft handoff, the mechanism provides better opportunity to transfer the link successfully in the handoff procedure. Thus, by carefully planning the overlay areas of cells, soft handoff can outperform hard handoff     

Characterization of soft handoff in CDMA systems

Many analytical approaches have been proposed for handoff analysis based on hard handoff in mobile communication systems. In code-division multiple-access (CDMA) systems with soft handoff, mobile stations (MSs) within a soft handoff region (SR) use multiple radio channels and receive their signals from multiple base stations (BSs) simultaneously. Therefore, the SRs should be considered for handoff analysis in CDMA systems. An analytical model for soft handoff in CDMA systems is developed by introducing an overlap region between adjacent cells and the handoff call attempt rate and the channel holding times are derived. Applying these results to a nonprioritized CDMA system, the effects of soft handoff and the mean cell residual time are investigated and compared with hard handoff     

CDMA局间硬切换流程及现场调测方法

在联通建设的CDMA网络中不同厂商提供的MSC和无线设备覆盖的边界上会产生硬切换，本文主要讲述CDMA局间硬切换的功能，类型及前向切换的一般流程，并介绍在上海联通组织的局间硬切换测试的背景及SKT进行硬切换测试的主要方法和调测过程，以及效果评估。     

WCDMA的切换参数对系统设计的影响研究

介绍了WCDMA系统的切换控制机制，比较了硬切换和软切换的不同特点，分析了切换参数对系统性能的影响。     

Performance Analysis of Trunk Network for Inter-MSC Soft Handoffs in CDMA Cellular Communication Systems

The soft handoffs between two adjacent MSC's should be employed to support the calls requesting handoffs to an MSC while minimizing the undesirable “ping pong” phenomenon of back-and-forth handoffsbetween two adjacent cells in conventional hard handoffs. In this paper, the soft handoff scheme between two MSC's is considered using the trunk between the packet routers for the two MSC's. The trunk network is proposed to support the inter-MSC soft handoff scheme in the service area with many MSC's. The probability that a°soft handoff to an adjacent MSC will be blocked due to the shortage of the trunk capacity is derived.