Performance of GSM networks with general packet radio services

Recently, most of the mobile network providers start to introduce general packet radio service (GPRS) in their existing GSM networks. GPRS is the technology that will enable more efficient Internet applications to run on mobile networks even before the installation of 3G systems. However, it is not yet clearly understood, how the new data services will affect the overall network performance. This paper provides a framework for analytical performance evaluation of a single GSM/GPRS cell based on a multidimensional Markov chain model. Important performance measures like new call and handover blocking probabilities, moments of the blocking period distributions, achievable average data rates and resource utilization are determined. Introducing a new connection admission control (CAC) algorithm, different partitioning strategies between GSM and GPRS resources are investigated. Finally, the influence of typical GPRS applications like Internet browsing on traditional GSM services has been studied.     

关于切换技术解决3G网络融合问题的综述

通过对无线通信网络的体系结构,运营方式,切换技术实现细节等方面的分析和研究,研究和探讨异构网络之间的切换技术,最终提出一个面向下一代无线通信网络的新型的基于IP的综合切换(Integrated Handover,IH)框架。IH技术的最终目标就是要解决移动通信网络中因网络异构、资源开销瓶颈等影响,成功地实现全球无线网络覆盖范围的低时延、高带宽、宽切换域、开销低和QoS保证的不同网络间顺畅的无缝切换。     

Modelling and optimization of power consumption in wireless access networks

The power consumption of wireless access networks will become an important issue in the coming years. In this paper, the power consumption of base stations for mobile WiMAX, fixed WiMAX, UMTS, HSPA, and LTE is modelled and related to the coverage. A new metric, the power consumption per covered area PC_area, is introduced, to compare the energy efficiency of the considered technologies for a range of bit rates. Assuming the model parameters are correct, the conclusions are then as follows. For a 5 MHz channel, UMTS is the most energy-efficient technology until a bit rate of 2.8 Mbps, LTE between 2.8 Mbps and 8.2 Mbps, fixed WiMAX between 8.2 Mbps and 13.8 Mbps and finally mobile WiMAX for bit rates higher than 13.8 Mbps. Furthermore, the influence of MIMO is investigated.For a 2 × 2 MIMO system, PC_area decreases by 36% for mobile WiMAX and by 23% for HSPA and LTE compared to the SISO system, resulting in a higher energy efficiency.The power consumption model for base stations is used in the deployment tool GRAND (Green Radio Access Network Design) for green wireless access networks. GRAND uses a genetic based algorithm and is applied on an actual case for the Brussels Capital Region, showing the possibilities of energy-efficient planning.     

Case study on handoff strategies for wireless overlay networks

One of the most challenging topics for next‐generation wireless networks is the process of vertical handoff since many of wireless technologies overlap each other and build a heterogeneous topology. Several parameters, pertaining to user/application requirements and network conditions, such as data rate, service cost, network latency, speed of mobile, and etc. must be considered in the handoff process of heterogeneous networks along with RSSI information. In this paper, adaptive fuzzy logic‐based vertical handoff decision‐making algorithms are presented for wireless overlay networks which consist of GSM/GPRS/Wi-Fi/UMTS/WiMAX technologies. The parameters data rate, monetary cost, speed of mobile and RSSI information are processed as inputs of the proposed fuzzy‐based systems. According to these parameters, an output value, which varies between 1 and 10, is produced. This output value is utilized to determine whether a handoff process is necessary or not and to select the best candidate access point in the vicinity. The results show that, compared to the traditional RSSI‐based algorithm significantly enhanced outcomes can be achieved for both user and network as a consequence of the proposed fuzzy‐based handoff systems. The simulation results are also compared with those of classical MADM (Multiple Attribute Decision Making) method, i.e. SAW (Simple Additive Weighting). According to the results obtained, the proposed vertical handoff decision algorithms are able to determine whether a handoff is necessary or not, properly, and select the best candidate access network considering the aforementioned parameters. Moreover, fuzzy‐based algorithm noticeably reduces the number of handoffs compared to SAW‐based algorithm.     

无线分组业务源模型与容量估算方法研究

业务源模型的建立可更好地研究无线移动通信网络的性能,并进行网络规划及系统性能评估。本文以UMTS网络的单用户业务为参考模型,分析其业务特征;以HTTP分组为研究对象,根据其主要行为特性建立业务源模型;针对无线移动应用环境中数据业务,提出了一种适用于3G网络规划的容量估计方法,并通过实例验证业务源模型易实现性及容量估计方法的易解析特性。采用有限状态机来描述业务模型的实现,对无线资源管理和流量控制具有一定的参考价值。     

移动通信网鉴权认证综述

随着移动通信网技术的演进,网络安全问题日益突出,如何在提供高质量通信服务的同时保护合法用户的隐私不被非法窃取、运营商网络不被入侵成为移动通信安全领域的一个重要问题。用户与网络的相互鉴权是用户和网络彼此判定对方合法性的重要手段,鉴权手段也随着网络演进而不断演进,从历代移动通信网络（GSM、CDMA、UMTS、LTE）鉴权认证技术入手,分析鉴权技术优缺点,并重点剖析了即将商用的第五代（5G）移动通信的鉴权技术、统一认证技术,最后对未来鉴权技术的发展进行了展望。     

Analysis of Skype VoIP traffic in UMTS: End-to-end QoS and QoE measurements

In the future Internet, multi-network services will follow a new paradigm in which the intelligence of the network control is gradually moved to the edge of the network. This impacts both the objective Quality of Service (QoS) of the end-to-end connection as well as the subjective Quality of Experience (QoE) as perceived by the end user. Skype already offers such a multi-network Voice-over-IP (VoIP) telephony service today. Due to its ease of use and a high sound quality, it becomes increasingly popular in the wired Internet.UMTS operators promise to offer large data rates which should suffice to support VoIP calls in a mobile environment. However, the success of those applications strongly depends on the corresponding QoE. In this work, we analyze the theoretically achievable as well as the actually achieved quality of IP-based voice calls using Skype. This is done performing measurements in both a real UMTS network and a testbed environment. The latter is used to emulate rate control mechanisms and changing system conditions of UMTS networks. The results show in how far Skype over UMTS is able to keep pace with existing mobile telephony systems and how it reacts to different network characteristics. The investigated performance measures comprise the QoE in terms of the MOS value and the QoS in terms of network-based factors like throughput, packet interarrival times, or packet loss.     

Security enhancements against UMTS–GSM interworking attacks

In this paper we first present three new attacks on Universal Mobile Telecommunication System (UMTS) in access domain. We exploit the interoperation of UMTS network with its predecessor, Global System for Mobile communications (GSMs). Two attacks result in the interception of the entire traffic of the victim UMTS subscriber in the GSM access area of UMTS network. These attacks are applicable, regardless of the strength of the selected GSM encryption algorithm. The third attack is an impersonation attack and allows the attacker to impersonate a genuine UMTS subscriber to a UMTS network and fool the network to provide services at the expense of the victim subscriber. Then, we propose some countermeasures to strengthen the UMTS network against the mentioned attacks with emphasis on the practicality in present networks. The proposed solutions require limited change of the network elements or protocols, insignificant additional computational load on the network elements and negligible additional bandwidth consumption on the network links.     

TETRA与GSM系统安全机制的研究与比较

数字集群系统TETRA和第二代移动通信系统GSM都是ETSI发布的数字移动通信标准,这两类系统的安全都基于私钥密码体制,安全协议基于共享秘密,提供匿名服务、认证和保密的安全服务,但实现机制有许多不同。TETRA还提供端端加密服务,确保整个传输过程的机密性。分析了两类系统的安全特征和安全机制,并进行了对比研究。     

Microelectronics in mobile communications: a key enabler

Mobile communications have grown beyond expectations since the beginning of the 1990s, mostly due to the introduction of second-generation (2G) digital solutions for mobile systems. Since the introduction of the first digital cellular networks in 1992, more than 250 million terminals have been sold. Europe has taken a leading position with products based on the Global System for Mobile Communications (GSM), which represent more than 60% of the 2G cellular equipment market. Of the top five GSM manufacturers, four are European companies: Nokia (Finland), Ericsson (Sweden), Alcatel (France), and Siemens (Germany). Massive manufacturer investments have resulted in low-cost solutions and the success of GSM. This article traces the evolution of 2G cellular terminals and discusses the GSM terminal architectures and technologies, showing the key role of microelectronics. We also discuss the challenges facing microelectronics in 3G systems such as the Universal Mobile Telecommunications System (UMTS) and wideband code division multiple access (CDMA), both to be introduced early in the next century. The European Community has consistently supported initiatives in the telecommunications domain. In particular, several ongoing MEDEA projects are associated with new developments in mobile communications     

IPTV service based on a content-zapping paradigm

Internet protocol television (IPTV) generically designates a real-time distribution service for multimedia contents over an IP network, such as the Internet. There are many advantages of IPTV deployment over current digital or air broadcast TV signals: integration, the use of the switched internet protocol (IP), the possibility to build home networks that can be used to share multimedia contents over different devices, the easy implementation of video on demand services and the usage of better compression and encryption standards. In order to implement this kind of service, it is extremely useful to have a system that can efficiently classify multimedia contents and users and distribute them in a customized way. This paper proposes a novel IPTV service for the distribution of personalized multimedia contents over IP networks based on the concept of content-zapping, in contrast to traditional channel-zapping: each client system receives a multimedia streaming that is automatically composed by the system based on the user preferences and the user will only interact with the system by requesting a content change or marking a content as favorite. The paper will describe the general functionality of the service and will present the detailed architecture of the IPTV server, the key component of the service infrastructure. The server must maintain a list of media contents residing in other systems and must keep a dynamic classification of the multimedia contents that are stored in its database. This classification is built and gradually refined based on the interactions between clients and multimedia contents. Special attention is given in the paper to the classification model, describing the general ideas that are used to automatically suggest multimedia contents to a specific user (that is characterized by his complete profile). A specific content may be suggested to the user based on the knowledge of the user profile and/or based on specific and dynamic information, such as the user position, the local temperature, date and time. The availability of this information obviously depends on the specific user device that is being used. The proposed system allows any client device to connect, allowing a high level of interoperability. It is also possible to use all the device capabilities and sensors, like Global Positioning System (GPS), accelerometers, light sensors, noise sensors, etc., thus creating a context environment that helps classify each user profile. These context-awareness mechanisms applied to mobile devices with wireless network (802.11b/g/n, WiMAX, GSM, UMTS, etc.) capabilities allow a better user experience and more accurate multimedia suggestions, due to the deep knowledge about the user device, network and environment. The system also allows the users to suggest contents to other users in the same “group of friends”. Several performance tests were already conducted and the results obtained show that the proposed system is very stable and fast, even for high increases on the number of users.     

Programmable mobile networks

Existing mobile systems (e.g., mobile IP, mobile ATM and third generation cellular systems) lack the intrinsic architectural flexibility to deal with the complexity of supporting adaptive mobile applications in wireless and mobile environments. We believe that there is a need to develop alternative network architectures from the existing ones to deal with the demands placed on underlying mobile signalling, adaptation management and wireless transport systems in support of new mobile services, e.g. interactive multimedia and web access. In this paper we present the design, implementation and evaluation of mobiware, a middleware technology that enables the introduction of new services in mobile networks. Mobiware provides a toolkit that service providers can utilize to build services that can dynamically exploit the intrinsic scalable properties of mobile multimedia applications in response to time-varying mobile network conditions. Based on an open programmable networking paradigm, mobiware runs on mobile devices, wireless access points and mobile-capable switch/routers providing a set of open programmable interfaces and distributed objects for adaptive mobile networking. Mobiware is software-intensive and is built on CORBA and Java distributed object technologies. The source code for mobiware v1.0 is freely available (comet.columbia.edu/mobiware) for experimentation.     

3G网络的移动视频监控系统

移动流媒体应用是基于3G独特高数据带宽的业务应用,是3G业务网络中最具市场潜力的增值业务类型。为了进一步推广移动流媒体技术的应用,该文将3G移动网络和固网视频监控结合起来,实现两者优势互补,提出了一种基于3G网络的移动视频监控系统模型,此模型能够弥补传统移动网络和固网的不足对移动视频监控系统的设计具有一定的指导意义。     

Enhancing WLAN/UMTS dual-mode services using a novel distributed multi-agent scheduling scheme

WLAN services are inexpensive and have a high bandwidth, while UMTS services provide wider coverage area and high mobility. Based on intelligent deduction, this study presents a novel service scheduling scheme for WLAN/UMTS dual-mode networks. The proposed system, Distributed Multi-Agent System (DMAS), consists of a set of problem-solving agents that autonomously process their own tasks and interoperate with one another by a shared database to reach a suitable schedule for dual-mode network services. A two-level control mechanism comprising local-control and meta-control is presented to achieve a high degree of goodness in service scheduling. Simulation results indicate that the Quality of Service (QoS) of the proposed discipline in terms of average delay and jitter is better than that of the pure UMTS network by 25% and 10%, respectively. The scheduling discipline can improve the service quality in multiple-mode networks.     

The IP multimedia domain: service architecture for the delivery of voice, data, and next generation multimedia applications

The IP Multimedia Subsystem (IMS) is defined by the 3 ^rd Generation Partnership Project (3GPP) as a new core network domain. IMS provides a service control platform that allows creation of new multimedia and multi-session applications utilizing wireless and wireline transport capabilities. In this paper we will cover the concepts and standards defining IMS and review the network architecture from a mobile perspective. We will see how IMS interacts with the Packet Switched Domain (e.g. Wireless LAN, GPRS, and UMTS networks), the Internet, and application services. Then we will examine the key IMS capabilities and show how they can be combined to create new mobile IP services. Finally, we present a software architecture, which is enabled by IMS and allows development of unique applications (with multimedia/multi-session functionality, single/multi-user, service to user). The software architecture is illustrated by an example of a prototype application. This work was done when the author was with Siemens Communications Inc., Boca Raton, FL     

The IP multimedia domain: service architecture for the delivery of voice, data, and next generation multimedia applications

The IP Multimedia Subsystem (IMS) is defined by the 3^rd Generation Partnership Project (3GPP) as a new core network domain. IMS provides a service control platform that allows creation of new multimedia and multi-session applications utilizing wireless and wireline transport capabilities. In this paper we will cover the concepts and standards defining IMS and review the network architecture from a mobile perspective. We will see how IMS interacts with the Packet Switched Domain (e.g. Wireless LAN, GPRS, and UMTS networks), the Internet, and application services. Then we will examine the key IMS capabilities and show how they can be combined to create new mobile IP services. Finally, we present a software architecture, which is enabled by IMS and allows development of unique applications (with multimedia/multi-session functionality, single/multi-user, service to user). The software architecture is illustrated by an example of a prototype application. This work was done when the author was with Siemens Communications Inc., Boca Raton, FL     

Mobility management for m-commerce requests in wireless cellular networks

Increasing number of sophisticated services provided by the current wireless communication systems have caused a significant transition from E-commerce to M-commerce. Enterprises have provided considerable new opportunities to promote their businesses accessible from small mobile devices such as personal digital assistant (PDA) or mobiles phones. These facilities are envisioned as the most convenient way of using M-commerce. Using such services from mobile phones or PDAs equipped with GSM/GPRS involve effective mobility management mechanisms in cellular networks—a popular architecture for wireless networks. Success of such systems will largely depend on the reliable connection for the roaming users. Consequently, Quality of Service (QoS) provision is one of the most challenging issues in the heterogeneous wireless network-based m-commerce systems. Such m-commerce systems enable users to roam between different wireless networks operators and geographical areas while providing interactive broadband services and seamless connectivity. This paper presents an analytical framework to model scarce channels in any cell for maximizing channel utilization and efficient handling of handover requests. Typical numerical experiments are presented to validate the analytical solution against simulation to study the effect of bursty traffic upon the performance of the cell in any cellular networks.     

An engineering approach to the design of a BcN control network

A broadband convergence network (BcN), which enables the convergence of communications and broadcasting services, the convergence of voice, video, and data services, and the integration of wired and wireless technology in order to provide high-quality broadband multimedia services, is an implementation example of a next generation network (NGN). To rapidly provide various new application services, a simple but feature-rich control network that performs all demanded control functions required for the provision of service is indispensable. However, there are few studies on control networks for BcN or NGN, and therefore we need to carefully consider the architecture and functions of the control network. The main purpose of this paper is therefore to present a BcN control network architecture and its design methodology. The network design process includes capacity and expense calculation process of control systems and control links, which enables the estimation of the overall network building cost. A reliability analysis for the control network is performed in detail based on various system redundancy policies. The proposed design methodology is expected to be utilized in the design of BcN control networks prior to field deployment.     

Secure mobile communication via identity-based cryptography and server-aided computations

In this paper, an identity-based key agreement protocol for securing mobile telephony in GSM and UMTS networks is presented. The approach allows two mobile phones to perform a session key agreement over an unsecured channel and between different providers using telephone numbers as public keys. Using the created session key, a symmetric encryption of all call data can be performed. Solutions to the problems of multi-domain key generation, key distribution, multi-domain public parameter distribution and inter-domain key agreement are presented. Furthermore, the proposed approach can be speeded up using server-aided cryptography, by outsourcing computationally expensive cryptographic operations to a high-performance backend computing server. The feasibility of the approach is illustrated by presenting experimental results based on a Symbian implementation running on N95-1 and N82-1 Nokia smartphones.