Design of the intelligent network segment of future mobile communication systems

Future mobile communcation systems will have to provide sophisticated services at quality levels comparable with those provided by fixed systems. An additional requirement is that these systems should be deployed by minimally impacting the existing infrastructures. In this respect an important component of future mobile communication systems is their intelligent network segment, which contains the logic of the services provided and the relevant data required for providing these services. In the context of this paper we study the problem of designing this segment. Our reference system is UMTS, but the practices presented herein may be applied to other systems as well. We identify two major problems, the first at the Mobility and Services Control Point (MSCP) level and the second at the Mobility and Services Data Point (MSDP) level. Our aim in this paper is the following. First, the overall design process is decomposed into a sequence of well-defined problems. Second, the problems are formally stated and theoretically formulated. Third, owing to the computational complexity associated with the theoretical formulations, we take the first steps towards the design of approximate (heuristic) algorithms. Finally we provide results and draw subsequent conclusions. © 1998 John Wiley & Sons, Ltd.     

Distributed traffic adaptive channel allocation

Dynamic channel allocation (DCA) schemes adapt to the time variant demand for channels in cellular mobile telephony systems. In this paper we propose a DCA scheme that smoothly changes the channel allocation by solving the following problem. Given a cell structure, a collection of channels, the frequency reuse distance, an allocation of channels to cells, and the number of active connections per cell, accommodate a new call or a new handover by minimally reconfiguring the established allocation of channels to cells. First, this problem is formulated as 0–1 quadratic programming problem. Next, we present a distributed, heuristic solution to the problem, which is based on the observed behaviour of the optimal algorithm. Finally, we present some simulation results on the performance and the feasibility of the distributed algorithm. © 1997 John Wiley & Sons, Ltd.     

Cost-Efficient Design of Future Broadband Fixed Wireless Access Systems

In future broadband fixed wireless access systems the overall design procedure is critical for their successful commercial deployment as well as their efficient operation and management. The problem addressed in this paper is twofold. Specifically, at a first phase the radio access network planning problem is addressed, which aims at finding the minimum-cost configuration of Access Point Transceivers (APTs) given thegeographical layout of the area to be covered. At the second phase, the interconnecting planning problem is addressed and aims at finding the minimum-cost configuration of the AccessPoint Controllers (APCs) and Inter-Working Units (IWUs) given the Access PointTransceivers layout. Both problems are formally defined, optimally formulated, and solved by computationally efficient heuristics. Finally, results are provided and subsequent conclusions are drawn.     

Efficient Location and Paging Area Planning in Future Cellular Systems

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.     

移动智能网中SCP的设计研究

给出了GSM（全球移动通信系统）和智能网结合的总体结构，指出了移动智能网中SCP（业务控制点）设计要解决的问题：（1）怎样与HLR（归属位置寄存器）进行通信以得到移动网中与移动有关的数据，（2）怎样解决智能业务与移动网中已有业务的交互．本文对这两个问题给出了解决办法．最后，为了让业务提供者设计与移动有关的业务，定义了三个与移动有关的新SIB（业务无关构件）     

Traffic-adaptive aggregate channel allocation for future cellular communication systems

A fundamental problem in third-generation mobile systems is the adaptation of the channel allocation to the traffic volume variation. Traffic adaptation may be partly achieved by the following (aggregate channel allocation) problem: given the set of channels, the cell structure and the load to be accommodated in each cell within a certain time zone, find the optimal allocation of channels to cells subject to the restrictions arising from the minimum permissible distance of cells where the same channel can be used at the same time. In this paper the problem is optimally formulated and efficiently solved by a heuristic. In the sequel the performance of a combined channel management scheme that uses the above problem for handling major traffic variations and a distributed DCA scheme for handling local traffic variations is assessed. Finally, results are presented and some concluding remarks are made. © 1998 John Wiley & Sons, Ltd.     

认知无线网络频谱感知与节点协同问题综述

认知无线电是被公认的解决移动无线网络频谱资源短缺和频谱资源动态分配问题的最有效和最有潜力的技术。基于认知无线电技术目前在移动无线网络中的实际应用情况,详细分析了认知无线网络目前所存在的无线频谱资源感知、探测和接入机制以及多用户节点协同等问题,并综述了频谱资源分配算法和认知无线网络容量问题的最新研究进展,最后提出用博弈论来研究解决认知无线网络多用户协同问题中的用户自私行为。     

Weighted Graph Based Clustering and Local Mobility Management for Dense Small Cell Network with X2 Interface

Along with the surge in mobile data, dense small cell network has become an effective method to improve system capacity and spectrum efficiency. However, because more small cells are deployed, the interference among dense small cells exacerbates. It also makes frequent handover for mobile users (UEs), which brings a great deal of signaling overhead to the core network. In order to solve the problems of interference and frequent handover, a novel clustering scheme for dense small cell network is proposed in this paper. The scheme is based on the weighted graph. First, we present a dense small cell clustering model based on X2 interface to minimize core network signaling overhead. To improve the usability of the model, we model the system as an undirected weighted graph. Then we propose the maximum benefit merging algorithm to reduce the complexity. This method enables adjacent small cells to cooperate and form virtual cellular cluster according to handover statistics information. Then we select cluster head (CH) according to certain rule in each cluster. Cluster head acts as the mobility anchor, managing the handovers between cluster members. This can reduce core network signaling overhead and the interference among small cells effectively. Compared with the 3GPP handover algorithm, the proposed clustering model in this paper can reduce the signaling overhead more than 70%. The simulation results show that the proposed clustering model can effectively cluster the dense small cell.     

Layered space–time block code for hybrid satellite–terrestrial broadcasting systems

Multiple‐input multiple‐output (MIMO) is a topic of high interest for the next generation of broadcasting systems. Even if they have begun to be proposed for the second generation of terrestrial digital TV, there are still gaps in the deployment of MIMO schemes in single‐frequency networks. This deployment becomes more critical when a hybrid satellite–terrestrial transmission is adopted because of the different aspects of the respective transmission links. In this paper, we propose to apply a layered space–time block code (LSTBC) for MIMO schemes in this hybrid transmission for next‐generation handheld (NGH) systems. The contribution of this paper is multi‐fold. First, we detail the land mobile satellite channel specifications describing the satellite link. Then, we propose to apply a MIMO scheme between the antennas of the satellite site and the terrestrial site. Then, we introduce the LSTBC scheme for NGH broadcasting systems. The proposed code is based on a layered construction designed to be efficient in shadowing regions. This efficiency is verified in a line‐of‐sight situation but also in low, moderate and deep shadow situations. The LSTBC scheme is then a very promising candidate for NGH systems with MIMO transmission. Copyright © 2012 John Wiley & Sons, Ltd.     

Ad hoc网络的扩频多址接入协议的研究与展望

Ad hoc网络将成为未来网络体系的基本组成部贩而扩频通信技术因其具有频带利用率高、抗干扰能力强等特点,被确认为移动通信系统首选的多址接入方式.鉴于此,本文介绍了扩频技术、Ad hoc网络以及其所面临的问题,对几种能有效解决Ad hoc网络存在的问题的扩频多址接入控制协议进行了分析比较,给出了研究过程中得出的结论.     

OMA DM‐based remote software fault management for mobile devices

Mobile devices (e.g. mobile handsets or PDAs) have gained much functionality and intelligence with the growth of mobile network technologies and the increased use of mobile services. As a consequence, mobile devices have become more complex and many related problems have occurred. Specifically, sudden rebooting and freezing problems caused by software faults decrease the availability of the mobile device and cause inconvenience to end‐users. To solve such problems, academia and industry have focused on Open Mobile Alliance (OMA) Device Management (DM); this method is the international de facto standard for mobile device management. In this paper, we propose a software fault management method to remotely determine and correct problems of mobile devices based on OMA DM. We present a definition of management objects and a method to collect them from mobile devices using the OMA DM protocol. We also present a method for debugging and correcting software faults using the collected information. Finally, we present a prototype implementation and performance evaluation to validate our proposed method. Results of the performance evaluation show that our proposed method is efficient and scalable in regard to network traffic overhead and response time. Copyright © 2009 John Wiley & Sons, Ltd.     

Data Replication for Improving Data Accessibility in Ad Hoc Networks

In ad hoc networks, due to frequent network partition, data accessibility is lower than that in conventional fixed networks. In this paper, we solve this problem by replicating data items on mobile hosts. First, we propose three replica allocation methods assuming that each data item is not updated. In these three methods, we take into account the access frequency from mobile hosts to each data item and the status of the network connection. Then, we extend the proposed methods by considering aperiodic updates and integrating user profiles consisting of mobile users' schedules, access behavior, and read/write patterns. We also show the results of simulation experiments regarding the performance evaluation of our proposed methods     

A Reservation Optimised Advance Resource Reservation Scheme for Deploying RSVP in Mobile Environments

One of the major problems of deploying Resource ReSerVation Protocol (RSVP) in mobile environments is called the advance resource reservation (ARR) problem. Conventional solutions to this problem waste too many network resources and increase the new Quality of Service (QoS) session blocking probability. In this paper, we propose a reservation optimised ARR scheme which constrains the number of advance reservation paths in a subnet and only allows the most eligible mobile nodes to make advance reservations. Furthermore, to evaluate the performance of the schemes, we build Markovian models of different ARR schemes using a formal performance modelling formalism named Performance Evaluation Process Algebra (PEPA). Our results indicate that the proposed reservation optimised ARR scheme can effectively balance the active and passive reservation blocking probabilities and achieves a better utilisation of the network resources, especially when the traffic intensity is high.     

移动通信技术的发展趋势

本文详细论述了现代移动通信技术的六大最新发展趋势：网络业务的数据化、分组化，网络技术的宽带化，网络技术的智能化，更高的频段，更有效利用频率，网络趋于融合，真向统一。了解、掌握这些趋势对移动通信运营商和设备制造商均具有重要的现实意义。     

Wireless resource virtualization: opportunities,challenges, and solutions

Wireless resource virtualization (WRV) is currently emerging as a key technology to overcome the major challenges facing the mobile network operators (MNOs) such as reducing the capital, minimizing the operating expenses, improving the quality of service, and satisfying the growing demand for mobile services. Achieving such conflicting objectives simultaneously requires a highly efficient utilization of the available resources including the network infrastructure and the reserved spectrum. In this paper, the most dominant WRV frameworks are discussed where different levels of network infrastructure and spectrum resources are shared between multiple MNOs. Moreover, we summarize the major benefits and most pressing business challenges of deploying WRV. We further highlight the technical challenges and requirements for abstraction and sharing of spectrum resources in next generation networks. In addition, we provide guidelines for implementing comprehensive solutions that are able to abstract and share the spectrum resources in next generation network. The paper also presents an efficient algorithm for base station virtualization in long‐term evolution (LTE) networks to share the wireless resources between MNOs who apply different scheduling polices. The proposed algorithm maintains a high‐level of isolation and offers throughput performance gain. Copyright © 2016 John Wiley & Sons, Ltd.     

An Efficient Multicast Routing Protocol in Wireless Mobile Networks

Providing multicast service to mobile hosts in wireless mobile networking environments is difficult due to frequent changes of mobile host location and group membership. If a conventional multicast routing protocol is used in wireless mobile networks, several problems may be experienced since existing multicast routing protocols assume static hosts when they construct the multicast delivery tree. To overcome the problems, several multicast routing protocols for mobile hosts have been proposed. Although the protocols solve several problems inherent in multicast routing proposals for static hosts, they still have problems such as non-optimal delivery path, datagram duplication, overheads resulting from frequent reconstruction of a multicast tree, etc. In this paper, we summarize these problems of multicast routing protocols and propose an efficient multicast routing protocol based on IEFT mobile IP in wireless mobile networks. The proposed protocol introduces a multicast agent, where a mobile host receives a tunneled multicast datagram from a multicast agent located in a network close to it or directly from the multicast router in the current network. While receiving a tunneled multicast datagram from a remote multicast agent, the local multicast agent may start multicast join process, which makes the multicast delivery route optimal. The proposed protocol reduces data delivery path length and decreases the amount of duplicate copies of multicast datagrams. We examined and compared the performance of the proposed protocol and existing protocols by simulation under various environments and we got an improved performance over the existing proposals.     

基于Java安全的移动代理访问权限的特化

移动代理是一种新的分布式计算模式，安全是其必须解决的问题。针对基于Java移动代理系统的移动代理权限问题，尝试提出一种解决方案。该方案主要包括2个方面内容：一是利用Java2安全机制实现移动代理权限的特化；二是采用资源代理模式实现移动代理基于角色的权限特化，对敏感资源进行双重保护。该方案既采取粗粒度的角色解决方案，又结合采取了低粒度的基于Java安全的解决方案，能有效地实现移动代理存取权限的特化。     

Inter-Data Commonality Detection for Spectrum Monitoring in Wireless Sensor Networks

Cooperative spectrum monitoring with multiple sensors has been deemed as an efficient mechanism for improving the monitoring accuracy and enlarging the monitoring area in wireless sensor networks.However,there exists redundancy among the spectrum data collected by a sensor node within a data collection period,which may reduce the data uploading efficiency.In this paper,we investigate the inter-data commonality detection which describes how much two data have in common.We define common segment set and divide it into six categories firstly,then a method to measure a common segment set is conducted by extracting commonality between two files.Moreover,the existing algorithms fail in finding a good common segment set,so Common Data Measurement(CDM)algorithm that can identify a good common segment set based on inter-data commonality detection is proposed.Theoretical analysis proves that CDM algorithm achieves a good measurement for the commonality between two strings.In addition,we conduct an synthetic dataset which are produced randomly.Numerical results shows that CDM algorithm can get better performance in measuring commonality between two binary files compared with Greedy-String-Tiling(GST)algorithm and simple greedy algorithm.     

Dynamic Spectrum Access with QoS and Interference Temperature Constraints

Spectrum is one of the most precious radio resources. With the increasing demand for wireless communication, efficiently using the spectrum resource has become an essential issue. With the Federal Communications Commission's (FCC) spectrum policy reform, secondary spectrum sharing has gained increasing interest. One of the policy reforms introduces the concept of an interference temperature - the total allowable interference in a spectral band. This means that secondary users can use different transmit powers as long as the sum of these power is less than the interference threshold. In this paper, we study two problems in secondary spectrum access with minimum signal to interference noise ratio (quality of service (QoS)) guarantee under an interference temperature constraint. First, when all the secondary links can be supported, a nonlinear optimization problem with the objective to maximize the total transmitting rate of the secondary users is formulated. The nonlinear optimization is solved efficiently using geometric programming techniques. The second problem we address is, when not all the secondary links can be supported with their QoS requirement, it is desirable to have the spectrum access opportunity proportional to the user priority if they belong to different priority classes. In this context, we formulate an operator problem which takes the priority issues into consideration. To solve this problem, first, we propose a centralized reduced complexity search algorithm to find the optimal solution. Then, in order to solve this problem distributively, we define a secondary spectrum sharing potential game. The Nash equilibria of this potential game are investigated. The efficiency of the Nash equilibria solutions are characterized. It is shown that distributed sequential play and an algorithm based on stochastic learning attain the equilibrium solutions. Finally, the performances are examined through simulations