Handover scheme for mobile cellular communication systems

A new scheme for minimising handover failure probability in mobile cellular communication systems, by exchanging channels between two mobiles moving in opposite directions across the endeavour area of adjacent cells is presented. The performance evaluation of the new scheme is carried out by computer simulation of a two cell model     

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.     

Adaptive methods for location management in mobile cellular networks

Future mobile cellular networks will include complex algorithms and procedures that make them able to react optimally to the fluctuating conditions (propagation, traffic, services, ...). Among these mechanisms, location management is an important one as it deals with an essential function of the mobile cellular networks: locate each subscriber to provide him/her with the subscribed services. In this paper, we present the location management methods that are currently implemented in cellular networks and the adaptive methods that have been proposed for future mobile cellular networks. These methods are evaluated for different scenarios and their performance are compared by means of simulations.     

A novel location management scheme for cellular overlay networks

In Beyond Third Generation (B3G) wireless communications, multiple overlays of wireless access networks may cooperate to allow a user access to novel services, the future demands of which will significantly increase the load on location management systems within the networks. In this paper, we introduce the reader to our novel proposals for providing efficient Mobile Terminal (MT) Location Discovery and Paging across an inter-worked network consisting a Digital Video Broadcast (DVB) network and Universal Mobile Telecommunication System (UMTS) network. We further present numerical and simulation analyzes of our scheme. The numerical and simulation results allow broadcast and cellular network operators to configure their inter-worked system to reduce location management and paging costs whilst controlling average latency. Our results demonstrate that our UMTS LA plus DVB paging schemes offer promise for efficient MT discovery in an inter-network environment that includes uni-directional broadcast network such as DVB; under realistic scenarios we achieve a minimum 4 times reduction in paging cost across the inter-network compared with independent paging systems. Furthermore, we briefly introduce further aspects of research that must be addressed in order to fully evaluate our proposals.     

Adaptive paging schemes for group calls in mobile broadband cellular systems

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.     

An efficient radio resource management strategy for adaptive OFDM cellular systems

This paper presents an efficient Radio Resource Management （RRM） strategy for adaptive Orthogonal Frequency Division Multiplexing （OFDM） cellular systems. In the proposed strategy, only those users who have the same distance from their base stations can reuse a same subcarrier. This can guarantee the received Carrier-to-Interference ratio （C/I） of each subcarrier to be acceptable as required by system planning. Then by employing different modulation scheme on each subcarrier according to its received C/I, system spectral efficiency can be gracefully increased. Analytical and simulation results show that the spectral efficiency is improved by 40% without sacrificing the Bit Error Rate （BER） performance and call blocking probability and system capacity of the proposed strategy is better than conventional systems.     

An efficient location and routing scheme for mobile computingenvironments

One of the most important issues affecting host mobility is the location and routing scheme that allows hosts to move seamlessly from one site to another. This paper presents a method that exploits the locality properties of a host's pattern of movement and access history. Two concepts, “local region” and “patron service” are introduced based on the locality features. For each mobile host, the local region is a set of designated subnetworks within which a mobile host often moves, and the patrons are the hosts from which the majority of traffic for the mobile host originated. These are used to confine the effects of a host moving, so location updates are sent only to its local area, and to those source hosts which are most likely to call again. Our scheme has the advantages of limiting location updates, and providing optimal routing, while increasing network and host scalability     

基于多跳蜂窝网的组位置管理策略

提出了一种成组进行位置管理的策略,分析了彼此临近的移动台组成一个自组织网的基本网络模型,提出了向中继点注册,由中继点进行信令压缩,组成组控制信令,成批向网络报告位置的位置更新的策略;采用M/M/n/n模型具体比较了批处理方案与传统方案的性能,说明作者的方案不仅减少了移动台的发射功率,还大量节省了频率资源,增加了系统的吞吐能力。     

An advanced location information management scheme for supporting flexible service provisioning in reconfigurable mobile networks

The evolution of third-generation mobile communications networks has nominated the requirements for flexible service provisioning, intelligent and customized charging, as well as location-aware service and data management as key enablers for the support of new advanced service offerings to mobile users. Our work is related to the design and implementation of a flexible service provisioning and reconfigurability management middleware for third-generation systems and beyond. The article focuses especially on the location-related features and functionality of our architecture, discussing the interactions required to accomplish location- and mobility-aware user profiling, service deployment and discovery, as well as charging and billing.     

A dynamic location management scheme for next-generation multitierPCS systems

Global wireless networks enable mobile users to communicate regardless of their locations. One of the most important issues is location management in a highly dynamic environment because mobile users may roam between different wireless systems, network operators, and geographical regions. A location-tracking mechanism is introduced that consists of intersystem location updates and intersystem paging. Intersystem update is implemented by using the concept of boundary location area, which is determined by a dynamic location update policy in which the velocity and the quality of service are taken into account on a per-user basis. Also, intersystem paging is based on the concept of a boundary location register, which is used to maintain the records of mobile users crossing the boundary of systems. This mechanism not only reduces location-tracking costs, but also significantly decreases call-loss rates and average-paging delays. The performance evaluation of the proposed schemes is provided to demonstrate their effectiveness in multitier personal communication systems     

An adaptive coding scheme with code combining for mobile radiosystems

The authors propose and study an adaptive error-control coding scheme for binary digital FM (BFM) mobile radio transmission. The scheme employs code combining through packet retransmissions. The number of transmissions of a packet is in proportion to the channel fading/noise levels, which is in contrast to time diversity techniques where a fixed number of repetitions of a data packet is performed even in the absence of channel errors. Furthermore, the receiver uses received signal envelopes as channel state information, which significantly improves the throughput and bit error rate (BER) performance. Performance of the proposed scheme is analyzed for frequency-flat Rayleigh fading channels with additive white Gaussian noise (AWGN), co-channel interference and random FM noise     

An adaptive Paris Metro Pricing scheme for mobile data networks

Because static pricing models (such as flat‐rate or tiered‐rate models) cannot improve user utility for subscribers and ease network congestion for operators during peak time, Smart Data Pricing has become an important incentive for mobile data markets. Paris Metro Pricing (PMP), which is a static pricing mode inspired by the pricing model for the Paris metro system, uses differentiated prices to motivate users to choose different train classes. Before choosing a class, people will consider their expected quality of service versus the prices that they are willing to pay. Even though PMP cannot guarantee the actual quality of service during service time, a balance between users' utilities and operators' revenue is achieved. In this paper, we propose an adaptive PMP scheme, so‐called APMP, which determines the dynamic access prices of different classes for the next 24 h. The accessible prices should try to increase the revenue while operators can serve more subscribers. Our simulation results show that APMP can significantly improve total revenue and average revenue per user for the operator. Copyright © 2016 John Wiley & Sons, Ltd.     

多业务CDMA蜂窝移动通信系统的功率控制

本文提出了多业务CDMA蜂窝移动通信系统的一种下行链路功率控制策略，系统的最优功率分配可以归结为求解归一化链路增益矩阵在有约束条件下的最大实特征值。在对系统的最优功率分配进行理论分析的基础上，给予了相应的仿真结果，并针对实际系统负载过重的情形，提出了按照业务优先级别逐步去除小区用户的功率控制策略。     

一种自适应的FRED缓存管理算法

如何保证业务流的公平性,特别是在存在UDP业务流的情况下,有效地保护TCP流一直是一个热点研究课题.本文提出了一种自适应的FRED缓存管理算法AFRED,通过动态的调节分组丢弃的门限,保护了TCP流,提高了系统的公平性,同时保证了带宽利用的有效性.算法的复杂度与FRED相近,但是能获得更好地性能.     

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.     

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。     

A collaborative location model for cellular mobile position location

In cellular network, several Time Difference Of Arrival (TDOA) location algorithms can be applied to mobile position estimation. However, each algorithm has its own limitations and none of them is proved to be the most reliable one in different channel environments. In this paper Kleine-Ostmann‘s data fusion model is modified and a collaborative location model which incorporates position estimate of two TDOA location algorithms is proposed.Analysis and simulation show that more reliable and accurate mobile position estimation can be achieved based on this model.     

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.     

An improved authentication scheme for mobile satellite communication systems

Recently, Lee et al. proposed a simple and efficient authentication scheme for mobile satellite communication systems. However, we find that their scheme is vulnerable to the smart card loss attack, the denial of service attack and the replay attack. To overcome the weaknesses of Lee et al.'s scheme, we proposed an authentication scheme for mobile satellite communication systems to improve security. The proposed scheme possesses the essential properties and security requirements, which should be considered for the authentication scheme of mobile satellite communication systems. Copyright © 2014 John Wiley & Sons, Ltd.     

An adaptive measured-based preassignment scheme withconnection-level QoS support for mobile networks

This paper presents a new adaptive bandwidth allocation scheme to prevent handoff failure in wireless cellular networks, known as the measurement-based preassignment (MPr) technique. This technique is particularly useful in micro/pico cellular networks which offers quality-of-service (QoS) guarantee against call dropping. The proposed MPr scheme distinguishes itself from the well-known guarded channel (GC) based schemes in that it allows the handoff calls to utilize a prereserved channel pool before competing for the shared channels with new call arrivals. The key advantage of the proposed MPr scheme is that it enables easy derivation of the number of channels that needs to be reserved for handoff based on a predetermined handoff dropping probability, without the need for solving the often complex Markov chain required in GC schemes, thus, making the proposed MPr scheme simple and efficient for implementation. This is essential in handling multiple traffic types with potentially different QoS requirements. In addition, the MPr scheme is adaptive in that it can dynamically adjust the number of reserved channels for the handoff according to the periodical measurement of the traffic status within a local cell, thus completely eliminating the signaling overhead for status information exchange among cells mandated in most existing channel allocation schemes. Numerical results and comparisons are given to illustrate the tradeoff