Group location management for mobile subscribers on transportation systems in mobile communication networks

We propose a new location tracking scheme for subscribers on transportation systems (TSs) in which a large number of fast-moving users have the same location as the TS. The group location tracking (GLT) scheme in which a group location update is performed instead of the IS-41's individual location update has been proposed. We propose a distributed GLT (DGLT) scheme based on several virtual visitor location registers (VVLRs) and representative identities. We analyze the GLT and DGLT schemes in view of the database (DB) access cost as well as the signaling cost under one-dimensional network architecture. Compared with the IS-41 scheme, the schemes based on group management generally have a lower signaling cost and a lower DB access cost due to a significant reduction in the number of location updates. As user mobility increases or the number of users on a TS increases, the performance of the group management schemes improves. The DGLT scheme, in which a corresponding home location register selects a closest VVLR among several possible VVLRs, generally has a lower signaling cost although a DB access cost is increased slightly compared with the GLT scheme. We also obtain the regions in which the DGLT is more efficient than the IS-41 and the GLT scheme. The DGLT scheme is an appropriate solution for high signaling cost systems and the GLT scheme is useful for high DB access cost systems.     

Group registration with local anchor for location tracking in mobile networks

In mobile networks, the location of a mobile user needs to be traced for successful and efficient call delivery. In existing cellular networks, as a mobile user changes his/her location area (LA), a location registration request is sent to the home location register (HLR) to update the user profile to point to the new LA. With a large number of mobile subscribers, this conventional registration strategy will incur a high volume of signaling traffic. We propose a new location registration strategy, called Group Registration (GR), which efficiently reduces the location registration cost by reporting location changes to the HLR for multiple mobile terminals (MTs) in a single location update request message. Specifically, the IDs of the MTs newly moving into an LA are buffered and sent to the HLR for location update in the route response message of the next incoming call to any MT in the LA. An analytic model is developed and numerical results are presented. It is shown that the proposed GR strategy can achieve significant cost reductions compared to the conventional strategy and the local anchor strategy over a wide range of system parameters. Moreover, the GR strategy results in a much smaller call delivery latency than the local anchor strategy.     

基于边缘追踪的虹膜定位算法

针对随机Hough变换造成的大量无效采样和无效累积问题，提出了基于边缘追踪的虹膜定位算法。首先通过寻找瞳孔内一点，找到了瞳孔边缘上的点。然后以Sobel算子为模板，根据点所在区域的方向特点进行一定邻域的边缘追踪。这样的定位算法边缘信息完整，边缘不存在间断的情况。因为只是在一定区域的搜索，所以定位的速度较快。同时由于算法对选取瞳孔边缘的点做出了改进，所以无需考虑光照所产生的光斑的影响。     

MB-OFDM-UWB系统基于时域扩展的盲频率跟踪算法

对多频带正交频分复用超宽带系统同步技术进行研究,提出一种基于时域扩展技术（TDS）的盲载波频偏（CFO）跟踪算法。利用数据符号与其时域扩展符号的特殊映射关系,在时域和频域分别推导出残余载波频偏的盲估计公式,并构建相应的时频跟踪环路。仿真结果表明,该盲算法具有比导频辅助法更优的跟踪性能。10dB信噪比下,基于TDS进行时频跟踪的残余CFO均方根误差均达到2×10?4,系统误比特率可达10?6数量级。     

基于传感器网络的多目标跟踪和特征管理方法

针对传感器网络下多目标跟踪时目标数量不断变化这一复杂情况,文中对多目标的跟踪和特征管理方法进行了研究。该方法由数据关联、多目标跟踪、特征管理,和信息融合所组成。其中未知数量多目标的跟踪和数据关联通过马尔科夫蒙特卡罗数据关联实现。通过信息融合来整合本地信息,获取所有相邻传感器的本地一致性,最终实现特征管理。试验证明,本方法能够在分布式的传感器网络环境下对多目标进行准确有效地跟踪和特征管理。     

基于ZigBee的机车无线定位方法研究

本文以设计一个机车无线定位管理系统为目的,首先介绍了时下主流无线定位技术,分析了它们的优点和缺点,讨论了其在机车定位应用方面的局限性,并在此基础上提出了基于对称双边到达时间测距算法和最小二乘定位算法的车站机车精确定位方法。证明了该方法对由于无线定位设备晶振频率差异导致的测量误差有较高的鲁棒性,具有比其他定位方法都高的定...     

An alternative strategy for location tracking

Mobile radio communications raise two major problems. First: a very poor radio link quality. Second: the users' mobility, which requires the management of their position, is resource consuming (especially radio bandwidth). This paper focuses on the second issue and proposes an intelligent method for users locating: the alternative strategy (AS). Our proposal is based on the observation that the mobility behavior of a majority of people can be foretold. If taken into consideration by the system, this characteristic can save signaling messages due to mobility management procedures, leading thus to savings in the system resources. Several versions of the AS are described: a basic version for long term events (i.e., received calls and registrations), and versions with increased memory for short and medium term events. The evaluation of the basic versions was performed using analytic and simulation approaches. It shows that storing the mobility related information brings great savings in system resources when the users have medium or high predictable mobility patterns. More generally speaking, this work points out the fact that the future systems will have to integrate users related information in order: firstly: to provide customized services and secondly: to save system resources. On the other hand, current trends in mobile communications show that adaptive and dynamic system capabilities require that more information to be collected and computed     

基于SIM300通讯模块城市智能交通系统

为了提高公交系统运行效率,实现城市智能化公交,本设计提出了基于SIM300通信模块与GPRS的智能公交系统。由STC12C5A60S2单片机作为主控芯片,成功设计GPS收集信息算法,通过采集数据,GPRS定位,确定站点的等车人数提供给公交司机,再将公交车信息反馈给站点乘客从而实现城市公交智能化。本设计提高了公交车的运行效率,实现了乘客与公车间的信息互通。     

基于隐马尔可夫模型的Cell-ID定位跟踪方法

针对传统基地台识别码(Cell-ID)定位方法精确度不高的问题,提出一种新的Cell-ID定位跟踪算法。该算法利用移动台当前的服务基站信息和相邻基站信息,分别加权计算出似然向量,通过隐马尔可夫模型来获得移动台的运动状态,最后利用最大后验概率准则求出移动台的位置。实验结果表明,该算法复杂度低,在服务基站稳定的区域内定位性能良好,达到通信委员会(FCC)的定位精确度要求。     

Robust mobile location estimation based on signal attenuation for cellular communication systems

A mobile location scheme using a weighted centroid method based on the ratios of distances between mobile and base stations derived from the differences of signal attenuations is proposed. The proposed method does not require perfect path loss and shadowing models, and is capable of being applied in existing systems without hardware modifications. Simulations demonstrate encouraging performance with only two base stations being available in shadowing environments. Additionally, the results of driving measurement show that the proposed method outperforms the Cell-ID method in a real GSM system.     

A new method for eye location tracking

A standard scleral search coil (SSC) system is supplied with a single three-axial transmitter (or with a triad of transmitters) and the direct magnetic coupling between the transmitting coils and the SSC is used for computing the eye location. The SSC's orientation components measured by the SSC system are involved in the location-tracking algorithm as well. The suggested method differs from traditional ones where the eye location is computed indirectly, relative to the measured location and orientation of a transitional three-axial magnetic sensor attached to the subject's head. The new method eliminates systematic errors caused by inaccurate situating the transitional sensor relative to the eye. It also eliminates systematic errors caused by imperfect orthogonality of the transitional sensor. It is found that an accurate location tracking with a single transmitter is possible only if orientation freedom of the eye is limited. To track the eye location with no orientation limitations, a triad of transmitters is employed. The resulting accuracy can be as good as +/- 1 mm (in a 200-Hz bandwidth) over a relatively large (0.5 x 0.5 x 0.5 m) operating region in the center of a 1 x 1 x 1 m SSC system. The analytical results obtained are confirmed with the help of computer simulations.     

More efficient location tracking in PCS systems using a noveldistributed database system

In personal communication services (PCS), the complete location information and subscribers' profiles are kept in a database called the home location register (HLR). Another database, the visitor location register (VLR), is used to store partial location information. When a mobile user is called, the system queries the HLR to determine the location of the called party. Distributed databases have been introduced to improve the efficiency of querying the HLR. This paper presents an alternative means of constructing a distributed database. The proposed database design employs fixed pointers to link distributed data. Each database contains a portion of the system's information as well as several pointers. The pointers identify the location of real data, enabling the system to obtain the required information efficiently. The database of the proposed design is markedly smaller than the fully distributed databases since each database of the proposed design stores only partial information. Subscriber information is stored only in one database, thus allowing a single database, rather than multiple databases, to be updated. The single update presented herein notably reduces the signal traffic load. If the caller is in the registration area of some HLR, which holds the called party's information, the response time is significantly decreased since the transactions are served only by the local database. This phenomenon is referred to as the calling locality. The proposed method effectively shares the database and the network loading that originates from several databases' tracking mobile users in a PCS system. According to the results presented, this method is highly effective for systems with a heavy load and high calling locality. The single update feature of the proposed design reduces the traffic in the signaling link and the processing load of a database. However, the proposed method includes no fault tolerance and therein differs from the fully distributed design     

基于TRIZ的麦克风—摄像机实时定位追踪发言人系统创新设计

TRIZ即发明问题解决理论,是一门可用来解决传统工程领域技术创新问题的方法学,但在新兴信息技术领域问题给出的解决方案较少。目前的麦克风—摄像机发言人实时定位追踪系统存在应用场所有限、实时性和精确度较低的问题。运用TRIZ理论中的三轴分析方法找到系统存在的技术矛盾和物理矛盾,提出了一种采纳了嵌入声纹识别技术和多传感器信息融合技术的优化创新设计方案,有效规避了现有的专利产品,也表明了TRIZ理论应用于新兴信息技术领域进行优化创新的可行性和高效性。     

基于仿射变换模型的图像跟踪系统的实现

文中设计研制了一种新型的基于仿射变换模型的实时图像跟踪系统。本跟踪系统已经通过实践检验,能够稳定的、准确的、快速的跟踪目标。并且系统有很大的升级潜力,除了能够满足仿射变换跟踪的要求之外,还能适用于其他的一些算法,构成鲁棒性更强的图像跟踪系统。实践证明该跟踪系统性能优于经典的相关跟踪系统。     

基于导频信号的OFDM通信系统信道估计与跟踪

讨论了在正交频分复用(OFDM)通信系统中,基于导频信号,采用投影逼近子空间(PAST)算法实现信道的跟踪估计,在快速变化的信道中,信道阶数自动跟踪,与传统的信道估计方法相比,信道估计精度提高,均方误差减小.通过计算机模拟仿真,验证了信道估计的跟踪性能得到了改善.     

基于TMS320C6424的智能交通系统实现

智能交通系统的不断发展也对系统性能提出了更多更高的要求。为了满足这些需求,使得系统能够更加有效、实时的对道路交通情况进行检测,实现了一种基于DSP芯片TMS320C6424的智能交通系统的电路设计。详细阐述了系统的电路结构和程序架构,指出了电路设计中的难点并提供了适合的解决方案。     

基于伪线性和输入估计的无源自适应跟踪算法

基于伪线性滤波算法和输入估计算法提出了一种对空中机动目标进行三维测向无源自适应跟踪的新算法。该算法把目标机动加速度看成是未知的输入向量附加到状态方程中,再利用状态向量扩维情况下的伪线性滤波算法对目标进行三维无源跟踪,跟踪过程中在对原来目标状态向量进行估计的同时估计目标加速度。仿真结果表明：该算法不需要对目标进行机动检测,即能够适应目标机动和非机动2种工作模式,实现对空中机动目标的自适应无源跟踪。     

基于嵌入式多核DSP 系统的并行粒子滤波目标跟踪

目标跟踪中的伺服系统需要极低的跟踪延时,由于粒子滤波跟踪算法固有的庞大计算量使得目标跟踪的精度大受影响。提出了一种粒子滤波跟踪算法在多核DSP 系统中的快速实现方法。首先,利用DSP 片上的包加速器来降低以太网相机的采集延时以及CPU 占用率,CPU 占用率从31%降低到10%;其次,通过手动操作高速缓存的刷新和实效,解决了多核同时共享图像数据带来的存储器一致性问题,多个核能通过高速缓存快速获取图像数据;最后,通过在多核核心上设置代理任务的方法,建立了一种多核并行计算的机制。粒子滤波算法中计算复杂度高的运算阶段被分配到多个核心上同时运算,实现了算法的低延时。实验结果显示8 核加速比达到7 倍以上,优于开放多处理标准 OpenMP 的并行优化效果。     

Pilot allocation based on user location information in massive MIMO systems

In order to so1ve the prob1em of pi1ot contamination in massive MIMO systems，a pi1ot a11ocation scheme based on user 1ocation information was proposed.The proposed scheme arranged the users according to the po1ar ang1e of the user 1ocation in the po1ar coordinate system with the base station of the ce11 as the po1e，and assigned the pi1ots sequentia11y.Combining with the characteristics of directiona1 antenna，the scheme can reduce the pi1ot contamination and improve the achievab1e rate of the system by contro11ing the mu1tip1exing distance of the pi1ot to a far range.Simu1ation resu1ts show that the proposed scheme can not on1y reduce the pi1ot po11ution between users，but a1so reduce the performance gap between different users and improve the fairness of the system.     

面向智能交通系统的物联网体系结构的研究

解决城市交通中存在的交通工具使用效率低等问题的一种方法就是应用物联网技术,设计智能交通系统.本文对智能交通系统和物联网技术的内涵做了简单的概述,重点论述了他们当前的发展状况以及今后的发展趋势.