Network architecture and signaling for wireless personalcommunications

A distributed microcellular architecture based on the IEEE 802.6 Metropolitan Area Network (MAN) is proposed, and is shown to meet anticipated personal communications service (PCS) needs. A method is presented to calculate MAN coverage in urban areas, and is used to demonstrate coverage of approximately 50 city blocks per MAN. A distributed subscriber database architecture is proposed to facilitate call setup, tracking of roamers and handoffs. To fully utilize MAN bandwidth, a quick method for the heat stations to switch on/off isochronous slots is proposed to facilitate adaptation to PCS traffic level variations. Call setup and handoff procedures are detailed. The PCS signaling overhead is calculated to be 15% of the capacity required to carry voice traffic     

OBS网络中一种新型的避免冲突方法

突发包冲突在无光缓存能力的光突发交换(OBS)网络中是一个尚未解决的问题.在对JET协议进行改进的基础上,文章首次提出了一种新型的突发包冲突解决方案,分析了其可行性及相对传统算法的优势.     

Connection admission control for mobile multiple-class personalcommunications networks

In this paper, we investigate the connection admission control problem in mobile personal communications networks. Since user mobility and multimedia traffic are important factors in personal communications networks, in contrast to other studies on this aspect which either focused on only single-class call connections or ignored user mobility, our study directly addresses the connection admission control for multiple-class calls with user mobility. A generic class of coordinate-convex admission control policies is considered. An efficient numerical method is proposed to derive the connection-level quality of service (QoS), and is verified with computer simulation results. The results obtained show that, besides offered load, user mobility can have a great impact on the connection-level QoS. The proposed analysis may be employed in a network design tool for studying the admission control policy and for selecting system parameters to satisfy the required connection-level QoS     

An optimal paging scheme for minimizing signaling costs under delaybounds

This letter introduces a method for minimizing paging costs in wireless systems with delay constraints. An optimal partition algorithm is proposed and the corresponding paging procedure is provided. Numerical results demonstrate that the new scheme outperforms other previous schemes for uniform and nonuniform location probability distributions     

光网络中保护光路的快速激活信令机制

针对通过用多协议标签交换(GMPLS)光网络中工作光路出现故障时保护光路的激活过程可能导致较长的故障恢复时间,成为限制应用的一个关键因素.本文从信令机制的角度研究缩短故障恢复时间的方法,扩展了现有的GMPSL信令协议,提出了一种保护光路的快速双向激活信令机制,分别从首尾两个方向同时激活一条保护光路,从而缩短了故障恢复时...     

Inverse two-way signaling scheme for optical burst switched networks

Optical burst switching is a promising all-optical switching technology for the next generation optical networks and signaling is one of the key components of it. According to propagation direction of control packets, the existing signaling schemes for optical burst switched networks can be roughly divided into three categories: one-way, two-way, and hybrid signaling. Since one-way signaling launches bursts without the acknowledgment of successful reservation of resources, it has small end-to-end delay but high data loss rate; two-way signaling uses a control packet to gather the state of links and needs the successful acknowledgment before sending out a burst, so it has large end-to-end delay but low data loss rate. A hybrid signaling gets a tradeoff of performance between one-way and two-way signaling. In this paper, we propose another hybrid signaling named inverse two-way signaling. By introducing the process of link state collection into one-way signaling, the inverse two-way signaling can decrease the data loss rate without increasing the end-to-end delay compared to one-way signaling. In other words, the inverse two-way signaling is an improved version of one-way signaling.     

基于移动代理的OBS网络的信令协议方案

文章提出一种基于移动代理和光突发交换(OBS)的光链路信令建立方法和协议方案.将主动包的结构应用于移动代理,使信令消息和数据流概括到一个突发包头(BHP)中,以此来缩短一个光路的建立时间.该方案可以实现分布式处理链路,以减轻网络中一个节点的工作量和加强每个网络节点的并行运算能力.     

A novel distributed dynamic location management scheme for minimizing signaling costs in Mobile IP

Mobile IP is a simple and scalable global mobility solution. However, it may cause excessive signaling traffic and long signaling delay. Mobile IP regional registration is proposed to reduce the number of location updates to the home network and to reduce the signaling delay. This paper introduces a novel distributed and dynamic regional location management for Mobile IP where the signaling burden is evenly distributed and the regional network boundary is dynamically adjusted according to the up-to-date mobility and traffic load for each terminal. In our distributed system, each user has its own optimized system configuration which results in the minimal signaling traffic. In order to determine the signaling cost function, a new discrete analytical model is developed which captures the mobility and packet arrival pattern of a mobile terminal. This model does not impose any restrictions on the shape and the geographic location of subnets in the Internet. Given the average total location update and packet delivery cost, an iterative algorithm is then used to determine the optimal regional network size. Analytical results show that our distributed dynamic scheme outperforms the IETF Mobile IP regional registration scheme for various scenarios in terms of reducing the overall signaling cost.     

An improved adaptive dual prediction scheme for reducing data transmission in wireless sensor networks

Wireless Networks - Currently one of the main problem for wireless networks is the medium access control. Hence, the number of data transmissions in wireless sensor networks should be optimized to...     

Local information-based congestion control scheme for space delay/disruption tolerant networks

Wireless Networks - The storage resources and communication opportunities in space delay/disruption tolerant networks (DTN) are usually very limited. Moreover, as the links in space DTN are often...     

Reducing signaling traffic in wireless ATM networks through handoff scheme improvement

We propose a new handoff call management scheme which reduces signaling traffic in wireless ATM networks and improves the efficiency of the virtual channel. Chaining followed by a make‐break algorithm is a suitable handoff scheme for various situations. In the chaining part of the scheme, a chain routing algorithm is studied and compared with the hop‐limiting scheme. When the algorithm is implemented in our scheme, it improves the performance of the existing scheme in call drop rates so as to reduce the signaling traffic in wireless ATM networks. Copyright © 2002 John Wiley & Sons, Ltd.     

Intermediate-node initiated reservation (IIR): a new signaling scheme for wavelength-routed networks

A problem of many distributed lightpath provisioning schemes is wavelength contention, which occurs when a connection request attempts to reserve a wavelength channel that is no longer available. This situation results from the lack of updated global link-state information at every node. In networks with highly dynamic traffic loads, wavelength contention may seriously degrade the network performance. To overcome this problem, we propose a new framework for distributed signaling and introduce a class of schemes referred to as intermediate-node initiated reservation. In the new scheme, reservations may be initiated at any set of nodes along the route; in contrast, reservations can only be initiated by the destination node in the classic destination initiated reservation (DIR) scheme. As a result, the possibility of having outdated information due to propagation delay is significantly lowered. Specifically, we consider two schemes within this framework, for networks with no wavelength conversion and for networks with sparse wavelength conversion, respectively. Theoretical and simulation results show that, compared with the classic DIR scheme, the new schemes can significantly improve the network blocking performance. The accuracy of the analytical models is also confirmed by extensive numerical simulations.     

基于半监督学习的社交网络用户属性预测

研究如何利用社交关系推测用户的隐藏属性(私隐信息),采用基于图的半监督学习方法推测用户属性。为了提高预测的准确率,提出利用属性聚集度评价属性推测的难易程度,并依用户节点标记的不同,设计不同的权重公式计算用户之间的关系强度。以“人人网”数据作为实验数据,对用户的兴趣与毕业学校进行预测,验证了方法的有效性。     

面向社交网络的隐私保护方案

针对社交网络的隐私安全问题,提出了一种新的社交网络隐私保护方案。首先设计了带陷门的属性加密算法,由属性权威机构与数据属主协同完成用户私钥的生成与分发,有效降低了数据属主的密钥管理代价。然后,通过令牌树机制控制用户对属性陷门的获取,实现了高效的属性撤销。安全性分析表明,该方案能够避免社交网络服务提供商与系统内部非授权用户的合谋攻击,且不泄漏用户的任何属性信息。实验结果证实,该方案在计算代价、存储代价等方面比现有方案更有优越性。     

VIDEO CODING SCHEME FOR ATM NETWORKS

A new variable bit rate layered coding scheme based on subband coding is given in this paper. It can make full use of the merits of ATM transmission, as well as compensation for the quality degradation caused by cell loss, which is an inherent problem of ATM networks, and thus a stable, high quality video transmission is achieved. This paper presents the coding scheme, cell construction and simulation results.     

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.     

ATM网络中CBR业务连接允许控制机制

该文提出了一种基于有限容量缓冲区下CBR业务信元丢失率和最小速率替换的线性近似连接允许控制机制，与原有的CAC机制相比，该文的CAC机制存在两个方面的改进：一方面，使用更合理、精确的CLR表达式，从而能够作出更为准确的连接允许判断：另一方面，能够提供服务质量服务。     

Vertical handoff algorithm in heterogeneous networks for reducing interference

A vertical handoff decision algorithm in heterogeneous networks composed of CDMA Cell Networks (CN) and Wireless Local Area Network (WLAN) is proposed to minimize the total interference in CDMA. The scope of WLAN is determined by minimizing interference and each communicating node shall handoff to WLAN as soon as it enters the scope. We first propose a model for heterogeneous networks, and based on it we obtain the close-form expression of interference. In order to minimize interference, we use simulation annealing method to get the WLAN radius, which is called basic algorithm. In order to reduce the interference further, we improve the basic and get the enhanced algorithm. Through numerical computing, we analyze the interference in condition of different call arrive rates, and results show that the enhanced can reduce interference more greatly than the basic.     

Advances in satellite CDMA transmission for mobile and personalcommunications

An ubiquitous network for multimedia personal communications (Personal Communications Network (PCN)) with small, individual low-cost terminals is one of the most ambitious worldwide projects for the 21st century that are being pursued nowadays. In the development of such PCN, Geostationary, Medium, and Low Earth Orbiting (GEO, MEO, LEO) satellite constellations will play a fundamental role to provide worldwide coverage for most services required by the end-user. The characteristics of efficiency and flexibility inherently required by that scenario suggest, amidst other possibilities, to take into special consideration a radio interface based on code division multiple access (CDMA) to ensure, in addition to the features mentioned above, a sufficient grade of power and spectral efficiency of the relevant satellite radio link. The aim of this paper is a review of the current status of those issues in the field of satellite CDMA transmission systems design that, in our opinion, appear fundamental to the successful operation of an efficient PCN. In particular, we survey the techniques for multiplexing, coding and transmission of direct-sequence spread spectrum (DS/SS) signals, and we touch upon the techniques for the minimization of the self-noise effect, and the related topics of power-control and multiuser detection. We also shortly address in this respect some technological aspects related to an efficient modem design via digital signal processing techniques. The final part of the paper deals more specifically with some typical issues of satellite transmission, namely the minimization of the detrimental effects of the nonlinear satellite transponder and of multipath propagation; the applicability of diversity reception to a multisatellite network is also addressed as possible means of performance boost     

Localization under anchor node uncertainty for underwater acoustic sensor networks

This paper deals with the problem of sensor node localization in the presence of uncertainty in anchor node location. Aqueous environments are prone to adverse effects of underwater currents. This adversity causes non‐negligible mobility to the anchor nodes deployed under water. Localization in the presence of uncertainty in the anchor node location is quite challenging. Also, the authors consider the ray‐bending property of underwater medium due to depth dependent sound speed, to furnish the accurate position estimate of the target node. Standard ray equations are used to model the path followed by acoustic rays in water. Maximum likelihood estimation is proposed to estimate the location of target node with uncertainty in anchor node positions and is compared with the scheme with exact knowledge of anchor node positions, and the results are reported. Monte Carlo simulation is used to assess the performance of the proposed method. Also, the Cramer‐Rao lower bound with uncertainty in anchor nodes is derived and described. Simulation results of the proposed algorithm outperform the existing algorithm with known anchor location by up to 49.4%, and hence, accuracy is improved in the proposed method.