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在低轨(LEO)卫星通信系统中,航行在国外的特殊终端位置更新时需查询国内地面站访问位置寄存器(VLR),导致了长距离的信令开销.为此,提出一种星上VLR数据库管理方案,使移动终端能通过查询星上VLR进行位置更新操作.将该方案运用于具体低轨卫星系统进行仿真.结果表明,该方案能优化系统的位置管理性能. 相似文献
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《无线电工程》2018,(3):193-197
天地一体化网络中,星基网络具有时变性,从而导致天地一体化网络难以采用传统地基网络体系完成终端管理。针对这一问题,提出低轨卫星或天基终端发生移动时主动更新位置信息,由低轨卫星充当天基终端的移动接入网关(MAG),由高轨卫星组成的网络充当天基网络的移动性管理代理(MMA),移动终端和低轨卫星的移动性控制信息由基于Pub/Sub的模型来管理,以维护MAG之间和MAG与地面网关(GW)之间的隧道,从而减少星间移动性管理消息交互和移动过程对传统PMIP网络的LMA和HA的依赖,提升了移动性管理的效率和可靠性。仿真结果表明,与传统MIP相比,基于Pub/Sub模型的天地一体化网络移动性管理方法以少量信令开销为代价,取得了传输时延方面的明显优势。 相似文献
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为了克服2G和3G移动通信网络位置管理方案的缺陷,4G长期演进(Long Term Evolution,LTE)采用了基于跟踪区列表(Tracking Area List,TAL)的位置管理方案。基于TAL的位置管理方案的性能取决于TAL分配方案。考虑到本地移动设备(User Equipment,UE)的活动区域相对固定,该文提出一种嵌入式马尔科夫链模型,用于分析本地UE的基于TAL的位置管理方案的信令开销。推导得到位置更新开销和寻呼开销的数学公式。利用这些公式,可搜索得到能使信令开销最低化的最佳TAL分配方案。 相似文献
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文章从GSM—R用户群体的特殊性出发,提出了将其用户终端按运动的规律性划分成不同的群体,以采用适当的位置管理方法来节省寻呼的开销观点。对静止的用户采用定向寻呼、规律性移动的用户采用追踪寻呼,对不规律性移动的用户采用排队式分组寻呼的办法来提高位置管理的效率。 相似文献
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怎样消除移动通信网络中的乒乓位置更新效应 总被引:2,自引:0,他引:2
本文介绍了移动通信网络中的乒乓位置更新效应的产生原因及各种方案对其抑制或消除的原理和性能。然后引出一种既简单易行又能从根本上完全消除乒乓位置更新效应的位置管理模型。这种模型还能与最优位置更新策略和最优寻呼策略同时使用 ,使位置管理开销降到最低。 相似文献
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通过对移动用户和网络特性的分析,结合核心网和无线侧,研究了CDMA网络的寻呼类型,给出语音和短信寻呼的基本方法,LAC(location area code,位置区码)位置区设置和周期性位置更新的重要策略,并对网络寻呼与某些业务的触发先后次序、关键定时器之间的冲突以及寻呼与移动终端的配合等问题进行了研究,提出了能够提高系统接通率和改善用户感知的寻呼策略方法:增加二次或三次寻呼、LAC边界避开话务密集地区、同一LAC下的周期性位置更新参数设为一致、周期性位置更新定时器无线侧设为小于网络侧等。 相似文献
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The blanket paging strategy in current mobile networks may waste a lot of wireless bandwidth. While keeping the standard location area (LA) based location update (LU) strategy unchanged, we propose an intra-LA LU scheme to reduce the paging cost. While a mobile terminal (MT) is residing in an LA with a cell called anchor cell, where the MT usually stays for a significant period, an intra-LA LU is performed whenever the MT changes its location between the anchor cell and the rest of cells in the LA. For an incoming call, either the anchor cell or the rest of cells in the LA is paged to locate the MT. Thus the paging cost is greatly reduced, especially when the called MT is located in its anchor cell. 相似文献
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Yang Xiao 《Communications Letters, IEEE》2003,7(8):358-360
An intra location area (intra-LA) location update (LU) scheme is proposed to increase paging accuracy for PCS networks. In the proposed scheme, each mobile terminal (MT) has a valid/invalid anchor-cell, which may be dynamically changed. A MT updates its anchor-cell information only when the status is changed, i.e., from the valid to the invalid or vice versa. Therefore, the intra-LA LU cost is minimized. Whenever the MT enters a cell, a timer is set. The MT realizes that the entered cell is its current anchor-cell if the timer expires before leaving the cell. An analytical model is proposed, and the optimal time threshold is derived explicitly. 相似文献
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We develop and analyze a hash-based paging and location update technique that reduces the paging cost in cellular systems. By applying a Bloom filter, the terminal identifier field of a paging message is coded to page a number of terminals concurrently. A small number of terminals may wake up and send what we call false location updates although they are not being paged. We compare the total number of paging and false location update messages with the cost of the standard paging procedure. Fortunately, the false location update probabilities can be made very small, and important bandwidth gains can be expected. The larger the size of the terminal identifier, the less probable are false location updates. Therefore, hash-based paging especially shows promise for IP paging in mobile IPv6 networks with 128-bit mobile host addresses. 相似文献
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Xiaoxin Wu Mukherjee B. Bhargava B. 《Wireless Communications, IEEE Transactions on》2006,5(4):839-848
Location update/paging strategies have been widely studied in the traditional single-tier cellular networks. We propose and evaluate a novel crossing-tier location update/paging scheme that can be used in a hierarchical macrocell/microcell cellular network. Location update is proceeded only in the macrocell tier, where a location area (LA) is made up by larger macrocells. A mobile user will stay in such a LA for longer time. Therefore, the cost on location update can be reduced due to the decreased frequency of location update. To reduce the paging delay, the paged mobile user will be searched in the macrocell tier only when the paging load is not high. Otherwise, it will be searched in the microcell tier, where a sequential searching method is applied. The operation for the scheme is simple, as the macrocell/microcell cellular network has the advantage because a mobile user can receive a signal from both a microcell and the overlaid macrocell. Analytical models have been built for cost and delay evaluation. Numerical results show that, at relatively low cost, the crossing-tier scheme also achieves low paging delay. 相似文献
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Jos Ramn Gllego María Canales ngela Hernndez‐Solana Antonio Valdovinos 《Wireless Communications and Mobile Computing》2012,12(16):1442-1457
In this paper, we analyze the problem of efficient paging for group call searches under realistic mobility patterns. Taking as a basis a location update scheme, based on the definition of an adaptive macro‐location area, adapted to the mobility pattern of the terminals, we characterize the residence probabilities in each location area of a generic macro‐area. With this information, we propose and evaluate different sequential group paging strategies, also taking into account their computational cost. Results show the suitability of some of the proposals (semiadaptive and hybrid schemes) and its applicability to new packet‐based broadband cellular systems. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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A hierarchical group location tracking (HGLT) based on grouplocation tracking and hierarchical location update is proposed toreduce the location management cost for terrestrialtransportation systems (TSs) in personal communication networks. A global group location update (GGLU) and a local group locationupdate (LGLU) are performed to provide an accurate position for auser. The GGLU informs a virtual visitor location register of thecurrently camped-on location area and the LGLU informs the servingmobile switching center of the currently camped-on cell. Althoughthe LGLU is done each time a TS moves into a new cell, it causessmall increment in the signaling cost due to localized updates andgroup updates compared with the previous group location trackingscheme. The proposed scheme significantly reduces the paging costbecause the scheme pages only a camped-on cell using the LGLUinformation. Compared with the previous schemes, the HGLT reducesthe location management cost, and it is more efficient as thecost for paging a cell increases. 相似文献
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On the problem of location update and terminal paging, many schemes using ring-paging strategies have been proposed. However, sequentially paging the rings surrounding the mobile user's last updated location may cause large paging cost. We propose a direction-based location update (DBLU) scheme using a line-paging strategy to reduce the paging cost. A moving direction identification mechanism using only simple computations detects the change of moving direction and updates the mobile's location. The numerical results show that our DBLU scheme achieves good performance when the paging cost is high 相似文献
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Dong-Jun Lee Dong-Ho Cho 《Communications Letters, IEEE》2001,5(4):148-150
In typical mobile communication systems, mobile station (MS) location information is updated when the MS crosses the location area boundary or the registration timer is expired. When a call attempt occurs, sequential paging rather than blanket paging is used to reduce the paging cost. We propose a new location update scheme in which to increase the paging accuracy, timer-based location update is performed within a location area. In this work, the optimum timer value of the area and timer-based location registration scheme with intelligent paging is derived. In case of a fixed location area, the optimum registration timer value depends on the speed and call arrival rate of the MS. If the speed or call arrival rate of the MS is high, location registration based on timer value should be performed frequently. Otherwise, location registration based on the crossing of location area is sufficient 相似文献
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The user mobility pattern (UMP) scheme is introduced for location update and paging in wireless systems where mobile terminals (MTs) maintain their history data in a database called user mobility history (UMH). During a location update, a UMP is derived from UMH and registered to the network. Unless the MT detects that it has moved out of the registered UMP, it does not perform any other location update. On the other hand, cells are paged selectively according to the cell entry times in the registered UMP upon a call arrival for the MT. The related data structures and the protocols for the UMP scheme are presented in the paper. The experimental results show that the UMP scheme outperforms the time-based and movement-based location update schemes as well as the blanket, selective, and velocity paging schemes. 相似文献
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Demestichas P.P. Demesticha V.P. Tzifa E.C. Kazantzakis M.G. Anagnostou M.E. 《Wireless Personal Communications》2000,12(1):83-109
Efficient resource utilisation in future cellular systems is partly related to the location update and paging operations, which rely on proper planning of location and paging areas, and the application of efficient paging schemes. Important is the design of low complexity planning algorithms that may enable the system to dynamically adapt to new traffic and mobility conditions. In this paper we define and solve versions of the location and paging area planning problems focusing also on algorithms that are applicable in real-time. Thus, they can be used to adapt location and paging areas to traffic and mobility conditions. Starting from a formal definition and an optimal formulation, we solve efficiently by means of a low complexity heuristic, a general version of the location area planning problem. Regarding paging area planning, we provide a low complexity algorithm, under the assumption that the scheme applied falls within the last interaction based paging (LIBP) category. The results presented, and the low cost and complexity induced by the proposed schemes, indicates that the real-time application of the schemes is feasible. 相似文献