Iub 口基于AAL2无线控制信令协议配置参数获取方案

介绍了Iub接口无线控制信令监测功能总体设计框架,针对Iub口协议栈的复杂性,主要利用Hash索引等技术,提出了一种Iub口基于从L2无线控制信令协议配置参数的获取方案.其中,公共传输信道上的协议参数通过智能猜测模块来获取,专用信道上主要通过协议关联模块来获取.专用信道上又根据RRC建立的信道分为两种情况:RRC建立在公共信道和专用信道.并结合实际分别探讨了这两种情况下如何从RRC和NBAP获取参数的实现过程.通过实际数据验证,能够快速、自动获取各传输信道的传输承载参数.     

卫星通信系统中网管信令传输优化及仿真

受限带宽下的网管信令突发碰撞是影响卫星通信系统网管信令传输效率的主要因素。针对窄带宽下信令突发引起的卫星网管信令传输效率低的问题,在综合分析卫通网管系统管理信息传输流程的基础上,对网管信令传输现状进行了仿真,提出了一种网管信令传输优化方案。该方案将Qo S技术应用于卫通网管信息传输,并通过排队调度和流量控制实现信息高效传输。仿真验证及系统实测表明,优化后的网管信令传输能力和效率得到了较大提升,该优化方案在提高卫星系统管理性能方面具有科学性和有效性。     

TD-SCDMA测试仪中Uu接口的RRC消息关联方案研究

在TD无线网络测试中,测试仪表的空中接口的数据解码和分析质量有着举足轻重的作用。RRC子层在空中接口中属于接入层,空中接口的相关功能的实现,如无线承载的建立和实现等都是在RRC信令连接的基础上进行的,因此RRC子层消息的关联是空中接口呼叫合成的关键所在。本文以MOC信令流程为例,根据RRC信令连接是否建立在专用信道上,对专用信道和公共信道上建立的RRC消息分别提出了相应的关联方案。经过测试,该方案确实可行,达到了研究的预期目的。     

一种B3G系统中的控制信令传输方法

文中针对B3G系统,提出了一种控制信令传输方法,为了提高传输的可靠性,将空时频编码引入到控制信令的传输中,使得控制信令在传输的过程中,能够同时获得空间分集、时间分集和频率分集,从而达到了提高传输可靠性的目的.最后,对提出的方案进行了仿真,并与3GPP LTE进行了对比,仿真结果表明,采用该方案能够获得更好的性能.     

一种B3G系统中的控制信道设计方法

本文针对B3G系统,提出了一种控制信道设计方案,为了提高控制信令传输的可靠性,将空时频编码引入到控制信道中,使得控制信令在传输的过程中,能够同时获得空间分集,时间分集和频率分集,从而达到了提高传输可靠性的目的。最后,对提出的方案进行了仿真,并与3GPPLTE进行了对比。仿真结果表明,该方案能够获得更好的性能。     

LTE网络RRC重建性能提升三板斧

RRC重建(RRC connection re-establishment)是UE处于RRC_CONNECTED状态,因为一些移动性管理或底层链路故障,导致连接中断,UE发起的空口资源重新建立的过程,以继续空口的RRC连接.重建的意义在于快速恢复空口业务,提高业务的连续性.RRC重建是由终端发起,目前商用网络终端发起重建原因在信令里仅显示为重配置失败、切换失败、Other三种原因,详细是什么原因导致发生重建,在RRC重建请求消息里并没有更多信息.所以需要从多条基站侧信令中分析RRC重建根本原因,但是日常定位重建问题原因的方法需要逐条信令查看,并与多条切换信令相对比,不仅繁琐,且分析准确性低.     

5G中新的RRC状态及在移动性管理中的应用

为满足mMTC(低功耗大连接)业务的低功耗大连接需求,5G系统需要引入一种新的RRC状态即RRC Connected Inactive。文章阐述RRC Connected Inactive的特点及应用场景、RRC Connected与RRC Connected Inactive状态间的快速状态转移,最后研究并提出当UE(用户终端)处于RRC Connected Inactive时UE主导的移动性管理技术,包括为了进一步节约UE功率开销及减少空口信令引入的RNA(无线接入网通知区域)。     

基于SDR的WCDMA信令跟踪分析软件设计及实现

随着3G通信技术的迅速发展,网络优化是3G通信的重要工作,首先介绍了WCDMA系统无线资源控制层（RRC）的逻辑结构和功能,接着,基于软件无线电思想,设计了RRC层信令跟踪分析方案,实现了系统信息解析和RRC层资源管理的功能,为网络优化提供了可靠的依据。     

卫星带宽功率双重受限情况下的高效传输方案

卫星通信传输信道属于典型的带宽功率双重受限信道,其功率、带宽利用率是评价传输方案优劣的重要指标。针对点对点对称传输的卫星通信链路的应用需求,提出了基于QPSK调制的PCMA传输方案,通过理论仿真和实际测试,与传统的基于16APSK高阶调制传输方案比较,在双向链路带宽利用率相同的情况下,该方案需要的接收信噪比更低、信道适应性更强,可以使功率利用率提高3 dB以上。     

TD-SCDMA小区接入异常综合分析

简要论述了TD-SCDMA系统小区接入流程及接入异常的总体分析过程;将TD-SCDMA小区接入异常所涉及的信令分为：建立RRC连接、初始直传NAS消息、安全模式控制、CallProc、建立RAB及上下行直接传输等6组（步骤）,并以大唐移动无线参数为例,逐一详细阐述了小区接入信令异常分析方法。     

Impact of mobile instant messaging applications on signaling load and UE energy consumption

Mobile Instant Messaging (MIM) applications transmit not only user-triggered messages (UTMs), but also keep-alive messages (KAMs) via radio access network, which induces heavy burden in control plane channel and wastes user equipment (UE) energy consumption. In this paper, we deduce the joint distribution of KAM period and UTM mean interval from the MIM application traffic characteristics. Correlating the joint distribution with radio resource control (RRC) state machine in LTE networks, we derive two analytical expressions for the control plane signaling load and UE energy consumption respectively. Then, the variation of signaling load and energy usage is demonstrated with different settings of RRC release timer, KAM period and UTM mean interval. The analysis indicates that KAM period is the upper bound of RRC release timer when reducing the signaling load. Besides, five times of UTM mean interval is the upper bound of KAM period when reducing the UE energy consumption and signaling load. These results can guide both network operators and MIM application developers to properly set control parameters for balancing the signaling load and UE energy consumption.

     

基于MDT数据优化小区空闲态与连接态 覆盖一致性的方法

本文提出了利用最小化路测数据(MDT)判断小区空闲态、连接态覆盖一致性的优化方法。根据最小化路测中的Logged和Imm数据分别判断某一地理栅格的RRC空闲态和连接态用户归属主服小区否一致。针对空闲态和连接态存在大量不一致栅格的小区,提出通过修改小区参数修改调整不同状态下覆盖区域,最终保证RRC空闲态、RRC连接态覆盖一致以达到降低发起业务后的非必要切换次数,提高户初始业务阶段速率,提升用户感知。     

WCDMA系统有效提高切换成功率的方法

在WCDMA系统实际的开发测试中,终端(UE)在专用信道(DCH)状态和前向接入信道(FACH)状态的相互切换时,若空中接口质量较差、上行有错包,则切换会失败。这种失败完全可以通过RNC的处理来避免,即在暂态过程中由MAC层自行决策是否可以切换,而不是协议描述的由RRC层执行切换。这种方法也可以应用于WCDMA的硬切换过程。实际应用证明,这种方法可以有效的提高切换成功率,提高系统的稳定性和可靠性。     

Evaluation of Level of Confidence and Optimization of Roll-back Recovery with Checkpointing for Real-Time Systems

Increasing soft error rates for semiconductor devices manufactured in later technologies enforce the usage of fault tolerant techniques such as Roll-back Recovery with Checkpointing (RRC). As RRC introduces time overhead that increases the completion (execution) time, time constraints (deadlines) might be violated. This is a drawback for a class of computer systems where the correct operation is defined not only by providing the correct outcome of an operation but also by ensuring that the deadlines are met. These computer systems are referred to as real-time systems (RTSs). In general RTSs are classified as soft and hard RTSs depending on the consequences of violating the deadlines. For soft RTSs, where consequences of violating the deadlines are not very severe, research have focused on optimizing RRC and shown that it is possible to find the optimal number of checkpoints such that the average execution time (AET) is minimal. While minimal AET is important for soft RTSs, it is more important to provide a high probability that deadlines are met for hard RTSs, where consequences of violating the deadlines may be catastrophic. Hence, there is a need of probabilistic guarantees that jobs employing RRC complete before a given deadline. Traditionally, AET analysis have been used for soft RTSs and worst case execution time (WCET) analysis along with schedule feasibility have been used for hard RTSs. In this paper we introduce a reliability metric, Level of Confidence (LoC), which is equally applicable to both soft and hard RTS. LoC is used as a metric to evaluate to what extent a deadline is met. The main contributions of this paper are as follows. First, we present a mathematical framework for the evaluation of LoC when RRC is employed. Second, we provide a proof to verify the correctness of the proposed expression. Third, in the context of hard RTSs, we provide a method to obtain the optimal number of checkpoints that maximizes the LoC. Fourth, in the context of soft RTSs where the maximal LoC may not be needed, but instead some LoC requirement is needed, we present an optimization method for RRC that finds the number of checkpoints that results in the minimal completion time while the minimal completion time satisfies a given LoC requirement. Fifth, we use the proposed framework to evaluate and compare probabilistic guarantees when RRC is optimized towards soft RTSs.     

On the performance of peaky capacity-achieving signaling on multipath fading channels

We analyze the error probability of peaky signaling on bandlimited multipath fading channels, the signaling strategy that achieves the capacity of such channels in the limit of infinite bandwidth under an average power constraint. We first derive an upper bound for general fading, then specialize to the case of Rayleigh fading, where we obtain upper and lower bounds that are exponentially tight and, therefore, yield the reliability function. These bounds constitute a strong coding theorem for the channel, as they not only delimit the range of achievable rates, but also give us a relationship among the error probability, data rate, bandwidth, peakiness, and fading parameters, such as the coherence time. They can be used to compare peaky signaling systems to other large bandwidth systems over fading channels, such as ultra-wideband radio and wideband code-division multiple access. We find that the error probability decreases slowly with the bandwidth W; under Rayleigh fading, the error probability varies roughly as W/sup -/spl alpha//, where /spl alpha/>0. With parameters typical of indoor wireless situations, we study the behavior of the upper and lower bounds on the error probability and the reliability function numerically.     

TD-LTE系统RRC子层研究与SDL仿真

介绍了TD-LTE系统RRC子层的功能模型及主要功能,提出了RRC子层的状态设计、各状态下的任务以及状态间的转换。最后详细描述了LTE系统RRC连接建立的过程,包括终端和网络端连接建立过程的MSC图、连接建立过程的SDL仿真流程及仿真产生的MSC图,验证了信号流程设计的正确性。     

Reliability design of direct liquid cooled power semiconductor module for hybrid and electric vehicles

With the global interests and efforts in popularizing low carbon vehicles, automotive power module has been becoming one of the fastest growing sectors in power semiconductor industry. As working in a harsh environment, the performance and reliability requirements of automotive module are stringent than industrial products. In this work, an integrated direct liquid cooled power module with enhanced reliability for hybrid and electric vehicles (HEV/EV) is developed. The design and assembly of the module were optimized in terms of performance, weight, cost and reliability. The module is integrated Al direct liquid cooling structure, leading to about 40% reduction of weight and cost and almost 50% reduction of junction to heat sink thermal resistance. Therefore, the junction temperature stays below the upper limit at the worst operation case which enhances the thermal reliability and lifetime. By incorporating advanced die lead bonding, the parasitics can be reduced by 50%, which is beneficial to efficiency and reliability. Furthermore, the die and terminal attach technologies are investigated to improve reliability. The lifetime prediction under a typical driving cycle shows that the proposed module is capable of working in the whole vehicle service period.     

区域配网规划和改造对提高供电可靠性研究

配电网供电可靠性是当下社会范围内共同关注的焦点话题,而供电可靠性容易受到硬件与软件层面相关因素的影响而有所下滑,导致供电效率和稳定性大受影响,严重时甚至可能引发安全事故。为了提高供电可靠性,可以从区域配网规划和改造入手,针对区域配网现状进行分析,研究其对供电可靠性的影响,再根据分析结果针对性地执行区域配网规划改造方案,能够显著提升供电可靠性。