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.     

An adaptive location management scheme for mobile broadband cellular systems

This paper presents an adaptive location management strategy that considers both location updating and paging by evaluating realistic mobility patterns. It proposes the design of an adaptive macro-location area based on multi-registration adapted to the terminals’ trajectory to reduce location updates. The solution includes an estimation of residence probabilities in the areas of the multi-registered list. This facilitates the design of a sequential paging scheme that reduces the average paging cost. Results show the capability of the solution to adapt to mobility patterns and traffic conditions in the network to minimize the overall location cost. Furthermore, the multi-registration approach and the reduced complexity in both network infrastructure and mobile terminals make the solution suitable for new packet-based broadband cellular systems.     

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.     

Passive location using CDMA mobile communication system based on repeater equipment

To overcome the drawback of a short operation range and low-resolution of a passive location system using a civil communication signal, the new idea that utilizes code division multiple access （CDMA） signal and repeater is disposed off. First, the CDMA passive location model and observation function are given, and the error source and error range are analyzed. Subsequently, the CDMA passive location algorithm in a repeater environment is described and simulated. The simulation result shows that the algorithm can provide the location value with high accuracy.     

卫星与地面移动通信系统综合环境下的一种位置管理策略

提出了一种在卫星与地面移动系统综合环境下的位置管理方案，即把两系统相重叠的小区设置为边界位置区(BLA)，漫游用户在BLA中进行位置更新，呼叫到达时，BLA中的位置寄存器配合系统进行寻呼。通过计算和数值分析证明该方案不仅可以使原有两系统结构不发生变化，并且能有效减小位置更新与寻呼造成的系统开销。     

Efficient and flexible location management techniques for wireless communication systems

We consider the problem of managing the information required to locate users in a wireless communication system, with a focus on designing and evaluating location management techniques that are efficient, scalable, and flexible. The three key contributions of this paper are: (1) a family of location management techniques, HiPER (for Hierarchical ProfilE Replication), that efficiently provide life‐long (non‐geographic) numbering with fast location lookup; (2) Pleiades, a scalable event‐driven wireless system simulator with realistic calling and mobility patterns derived from several months of real traffic traces; and (3) multi‐day simulations comparing our proposed location management techniques with current and previously proposed techniques on a realistic geographical and network topology. This revised version was published online in June 2006 with corrections to the Cover Date.     

A TCP-tailored approach to location management in mobile ad hoc networks

The main location management proposals in mobile ad hoc networks have, as a common characteristic, two distinct phases: the location query of the position of a destination node and the transmission of a flow toward the destination node. This letter proposes to send the initial packet of a flow to learn the position of its destination instead of adopting a dedicated query packet. Such an approach specially benefits TCP flows. This TCP-tailored approach can be applied to previous proposals in location management with minor changes in their particular features. We show that the proposed TCP-tailored approach reduces the cost of location management for TCP flows with respect to conventional schemes. We also evaluate the benefits that different location services take from the TCP-tailored approach.     

Optimal relayed mobile communication systems

Recently, D.T. Chiang and R.F. Chiang (1986) considered a relayed mobile communication system with evenly spaced mobile relay stations (spacecraft) moving at the same speed from an origin towards a destination. Such a system can be considered as a consecutive-k-out-of-n line. They gave equations for computing the mean number of stations needed for a successful relay and studied the optimal choice of k to minimize the mean number. In the present work, the authors show that it is always better to replace a consecutive-k-out-of-n line by a consecutive-1-out-of- n line, but with k redundancy. The problem of choosing an optimal k still has no closed-form solution, but it is much more tractable than the original problem studied by Chiang and Chiang. Exact solutions are provided for a wide range of parameters     

Satellite land mobile communication systems

The emergence of satellite land mobile services over the last 10 to 15 years is described together with future trends. The difficulties of providing a commercially viable voice service are discussed and alternatives, such as inclined orbit systems and satellites with very large antennas, are suggested as ways in which the initial disadvantages might be overcome. Data services for satellite land mobile traffic and the possibilities of including radio determination of vehicle location as part of these data services are also considered. Future systems, which could have their architecture strongly influenced by the use of onboard processing, are discussed     

Chain authentication in mobile communication systems

Digital mobile telecommunication systems have become a future trend in personal communications services (PCS) networks. To satisfy the demand for high quality services, security functions, including the authentications of communication parties and the confidentiality of communication channels, must be embedded into mobile communication systems. This work presents an authentication scheme to support the security functions. The proposed protocol significantly improves the performance of authentications and ensures the security of mobile communications in a large-scale communication network with multiple service providers. This revised version was published online in June 2006 with corrections to the Cover Date.     

Reconfigurable terminals for mobile communication systems

Mobile phones of the future will be the access terminals to many different types of service. This will mean that they must be able to reconfigure themselves to support the differing service requirements placed upon them. At the root of this ability to reconfigure must be components and architectures that allow such flexibility, and so the key objective of the work programme on terminals within the Virtual Centre of Excellence in Mobile and Personal Communications (Mobile VCE) has been the design, definition and performance evaluation of key components and architectures for future generation reconfigurable terminals     

Emerging mobile and personal communication systems

The market demand for wireless communications has been demonstrated by the rapid growth of different second-generation wireless technologies that are optimized for particular applications and environments. Obvious examples include: digital cellular systems like GSM, ADC, PDC,and DCS1800 for widespread vehicular and pedestrian services, and cordless telecommunication systems based on CT2, DECT, and PHS standards for residential, business, and public cordless access applications. Efforts are also underway to consolidate the various radio environments and applications under a single standard for third generation wireless, i.e., FPLMTS. In the area of personal mobility, with the recent availability of “personal” numbers in various countries (e.g., 500 numbers in the United States), many fixed network operators are starting to offer such personal mobility services as “personal number service” and “number portability”. These services represent initial stages of full personal mobility that will be provided by UPT in both wireline as well as wireless environments. The expected heavy demand for PCS in the United States and the underlying market/regulatory forces are driving the standardization and business activity. A number of air interface standards for the 1900 MHZ PCS band are being considered, which are based on TDMA, CDMA, and FDMA technologies singly or in combination. Many are variations of existing digital cellular and cordless telecommunications technologies. PCS networking standards are also being developed; both for standalone systems and for systems that will utilize public switched network capabilities     

Vehicle location in cellular mobile radio systems

A tutorial discussion of vehicle location as used to control cellular mobile radio systems is presented. Early concepts and misconceptions concerning vehicle location are described, and the relation between location "accuracy" and system performance optimization is discussed. Measurement parameters commonly used for vehicle location are described, and considerations relating to the algorithm used in the location process are presented.     

Innovative approach to interspan fibre break location in fibre amplifier repeatered communication systems

A proposed modification to the component geometry of a fibre amplifier repeater which allows on on-board cable fault location facility to be incorporated is reported. The measurement technique, based on OTDR, allows cable breaks in the section of optical fibre between two fibre amplifier repeaters to be located.<>     

Telemedicine using mobile satellite communication

With a view to providing paramedical care within moving vehicles, a telemedicine technique using mobile satellite communication was proposed. With this technique, the diagnosis from a specialist and the emergency care under his/her instructions would be available on the spot without unnecessary delay. The characteristic problems of this technique were identified as: channel capacity, size of the system, reliability of vital sign transmission, real-time operation and electromagnetic interference. Measures against these problems were devised, and their effectiveness was analyzed. A data format was designed and an experimental system was developed. The system can simultaneously transmit a color image, an audio signal, 3 channels ECG and blood pressures from a mobile station to a ground station. It can transmit an audio signal and error control signals from a ground station to a mobile station in a full duplex mode. Fundamental transmission characteristics were measured in a fixed station. Finally, experiments of medical data transmission were conducted with a navigating ship and an aircraft flying an international route. The measured threshold values of C/N_o to guarantee satisfactory data reception were well below the lower boundary of C/N_o of the communication link. Consequently, the feasibility of this technique was verified     

移动通信网络最优通信节点拓扑定位方法研究

为了提高移动通信网络的覆盖能力,提出一种基于自适应分层路由探测的移动通信网络通信节点拓扑定位方法。采用Sink节点分组协调机制进行通信网络负载均衡控制设计,同时采用最短收发路径寻优方法进行通信节点的自适应组网设计,计算网络链路节点的正确传递概率密度函数,求解其最优值,以此为优化目标进行分层路由探测,实现通信节点拓扑定位。仿真结果表明,采用该方法进行通信节点拓扑定位,提高了移动通信网络的覆盖度,以最少的节点实现最大范围的通信覆盖。     

Emergency management systems using mobile cloud computing: A survey

Among today's rapidly evolving technologies, artificial intelligence plays a significant role in making decisions by a system without any human intervention. An Emergency Management System (EMS) is a decision support system where emergencies such as tsunami, landslide, fire, cyclone, and electrical short circuits can be prevented with prior detection and can be addressed immediately in an efficient way after the emergency occurred. Automation of EMS can avoid or manage multiple emergencies, which alternatively can save lives, economy, and environment. Quality demand response with fast data transfer, error minimized computation, and effective resource utilization is very much essential while developing the EMSs. This will provide a bridge between the technology and emergency responders. Resource-limited smart devices can be made rich in computational behavior by outsourcing their requirements such as storage, virtual servers, and web services using Mobile Cloud Computing (MCC). In this work, we have done a detailed survey on both MCC applications and EMS applications proposed in the literature, and we have also identified the design challenges handled in both MCC and EMS applications. We have presented the design challenges and possible solutions for development of EMS using MCC. We propose an architecture for building an automated EMS using MCC. Finally, we conclude the paper with specific future directions.     

移动通信网络的维护和管理

结合哈尔滨移动通信公司网络优化工作实际,在载波的管理、通信应急保障等方面介绍如何做好移动通信网络维护、管理工作.     

LEO/MEO systems – Global mobile communication systems

LEO/MEO systems are moving from a dream to a reality, their global reach is becoming apparent with the launch of the first LEO satellites. The global mobility offered by these systems is expected to have a profound effect on the way that organizations and individuals operate. Billions of dollars are invested in the research and development of LEO/MEO based communication systems, and larger amounts will be needed for their ongoing operation and use. Many global satellite based systems have been announced over the last decade, Ellipsat, Globalstar, ICO, Iridium, M‐Star, Odyssey, Orbcomm, and Teledesic, are just a few of the many systems in deployment or under development. Being such a risky venture, limited experience exists in developing and managing large scale civilian satellite based mobile communication systems. Many interesting and challenging research issues are faced by the designers and operators of such systems. This paper presents the different approaches to the configuration of the various LEO and MEO based communication systems. It compares their advantages and disadvantages, and analyzes their economic viability. Based on the analysis, it is possible to identify the specific roles that each type will play in the global communication market. The paper presents and discusses some of the important research areas involved in their development, configuration, maintenance, operation and management. In particular, it introduces the problem of gateway placement in LEO/MEO systems and presents a mathematical formulation of the problem. This revised version was published online in June 2006 with corrections to the Cover Date.     

Enhanced centralized management of gateways using redirection-based rules sharing for mobile network virtualization

One of the current issues in the peer-to-peer streaming systems is to supply sufficient upload bandwidth for continuous streaming of high-quality video channels. The helpers as upload bandwidth boosters can improve the streaming capacity of system, so that the imbalance of upload bandwidth between different video channel overlays is compensated. With the deployment of helpers as an intermediate level between server and peers, building and maintaining the optimal peer-helper topology becomes a challenging task since the one-directional nature of video streaming from the helpers to users makes the well-known reciprocity-based algorithms useless. Because of selfish behavior of peers and lack of a central authority among them, selection of helpers requires implicit coordination. In this paper, we design a decentralized, stochastic approximation helper selection mechanism which is adaptable to supply and demand pattern of various video channels. Our regret-tracking-based solution for allowing peers to strategically exploit their shared resources is guaranteed to converge to the correlated equilibria (CE) among the helper selection strategies. Online convergence to the set of CE is achieved through the regret-tracking algorithm which tracks the equilibrium in the presence of stochastic dynamics of helpers’ bandwidth. The resulting CE can help to select proper cooperation policies. Simulation results demonstrate that our algorithm achieves good convergence, load distribution on helpers and sustainable streaming rates for peers.