Showing papers on "GSM published in 2005"

Location-based Services: Fundamentals and Operation

Abstract: Preface. List of Abbreviations. 1 Introduction. 1.1 What are Location-based Services? 1.2 Application Scenarios. 1.3 LBS Actors. 1.4 Standardization. 1.5 Structure of this Book. Part I: Fundamentals. 2 What is Location? 2.1 Location Categories. 2.2 Spatial Location. 2.3 Conclusion. 3 Spatial Databases and GIS. 3.1 What are Spatial Databases and GIS? 3.2 Geographic versus Spatial Data Models. 3.3 Representing Spatial Objects. 3.4 Features and Themes. 3.5 Algorithms of Computational Geometry. 3.6 Geography Markup Language. 3.7 Conclusion. 4 Basics of Wireless Communications. 4.1 Signals. 4.2 Propagation of Radio Signals. 4.3 Multiplexing and Multiple Access. 4.4 Conclusion. 5 Cellular Networks and Location Management. 5.1 Overview of Cellular Systems. 5.2 Principles of Cellular Networks. 5.3 Mobility Management. 5.4 Common Concepts of Location Management. 5.5 Location Management in CS Networks. 5.6 Location Management in PS Networks. 5.7 Conclusion. Part II: Positioning. 6 Fundamentals of Positioning. 6.1 Classification of Positioning Infrastructures. 6.2 Basic Positioning Methods. 6.3 Range Measurements. 6.4 Accuracy and Precision. 6.5 Error Sources. 6.6 Conclusion. 7 Satellite Positioning. 7.1 Historical Background. 7.2 Orbital Motion of Satellite Systems. 7.3 Global Positioning System. 7.4 Differential GPS. 7.5 Galileo. 7.6 Conclusion. 8 Cellular Positioning. 8.1 Positioning in GSM Networks. 8.2 Positioning in UMTS Networks. 8.3 Assisted GPS in GSM and UMTS. 8.4 Positioning in other Cellular Systems. 8.5 Conclusion. 9 Indoor Positioning. 9.1 WLAN Positioning. 9.2 RFID Positioning. 9.3 Indoor Positioning with GPS. 9.4 Non Radiolocation Systems. 9.5 Conclusion. Part III: LBS Operation. 10 Interorganizational LBS Operation. 10.1 LBS Supply Chain. 10.2 Scenarios of the LBS Supply Chain. 10.3 Supplier/Consumer Patterns for Location Dissemination. 10.4 Privacy Protection. 10.5 Conclusion. 11 Architectures and Protocols for Location Services. 11.1 GSMand UMTS Location Services. 11.2 Enhanced Emergency Services. 11.3 Mobile Location Protocol. 11.4 WAP Location Framework. 11.5 Parlay/OSA. 11.6 Geopriv. 11.7 Conclusion. 12 LBS Middleware. 12.1 Conceptual View of an LBS Middleware. 12.2 Location API for J2ME. 12.3 OpenGIS Location Services. 12.4 Conclusion. 13 LBS - The Next Generation. Bibliography. Index.

Accurate GSM indoor localization

Abstract: Accurate indoor localization has long been an objective of the ubiquitous computing research community, and numerous indoor localization solutions based on 802.11, Bluetooth, ultrasound and infrared technologies have been proposed. This paper presents the first accurate GSM indoor localization system that achieves median accuracy of 5 meters in large multi-floor buildings. The key idea that makes accurate GSM-based indoor localization possible is the use of wide signal-strength fingerprints. In addition to the 6-strongest cells traditionally used in the GSM standard, the wide fingerprint includes readings from additional cells that are strong enough to be detected, but too weak to be used for efficient communication. Experiments conducted on three multi-floor buildings show that our system achieves accuracy comparable to an 802.11-based implementation, and can accurately differentiate between floors in both wooden and steel-reinforced concrete structures.

Mobile Telephone All In One Remote Key Or Software Regulating Card For Radio Bicycle Locks, Cars, Houses, And Rfid Tags, With Authorisation And Payment Function

Abstract: The “All In One Remote Keys” (AIORK) for (GSM, UMTS, W-LAN, Bluetooth, RFID-transceiver) mobile phones and/or extension kits is a universal key for all kind of locks, gates or entrances and it has a direct payment- and clearing function for electronic (Bluetooth, WLan, GSM and esp. NFC RFID-) cash payments for all consumed accesses, services or information. The input can be made by fingerprint or oral with direct biometric sensor confirmation. The NFC transceiver is for: Info-download, direct-cash-payment, access-control, function control, authentification of internet-auctions, -betting and -stock transactions and of such information and over all for RFID-tag identification of worthy objects, electronic devices and parts etc. with GSM based Internet website or account clearing. And it is running and lets manage a mobile-phone-platform with video-clip-hitcharts, which is with fingerprint-sensor authentication the best quality bringing solution for e.g. news etc. looking mobile video phone user/consumer and which is so finally the only functioning or establishing mobile video phone solution.

Toward multistandard mobile terminals - fully integrated receivers requirements and architectures

Abstract: In the recent past, there has been an evolution in wireless communications toward multifunctions and multistandard mobile terminals. Reducing the number of external components to a minimum is key when the same mobile terminal has to process several different standards. Highly integrated solutions in low-cost silicon technologies are thus required. Zero-IF and low-IF receiver architectures are most suitable for a high level of integration. This paper presents a review of global system for mobile communications, universal mobile telecommunication system, Bluetooth, and wireless local area network (IEEE802.11a, b, g and HiperLAN2) standards, likely to all be present in the "universal" terminal of the future, enabling global roaming and wireless connectivity. The various standards are analyzed in order to find the optimal architecture and the building-block specifications for the receive section, with particular care to the RF front-end. State-of-the-art solutions are discussed, with emphasis on direct conversion CMOS implementations. A multistandard architecture for a fully-integrated CMOS receiver is proposed.

Passive radar using Global System for Mobile communication signal: theory, implementation and measurements

Abstract: Passive radars using illuminators of opportunity have attracted much attention in the international radar community. One existing radio transmission system that may be utilised for this purpose is the Global System for Mobile communication (GSM). The paper presents a study showing the feasibility of using a GSM signal for passive radar. The analysis of the GSM waveform, and any significance or influence it has with respect to the passive radar design considerations are investigated in detail. The paper describes fully the design and implementation of a low-cost GSM-based passive radar prototype in addition to the associated signal processing scheme. Numerous measurements for various ground-moving targets were investigated extensively. The preliminary processing results demonstrate the feasibility of using GSM signals as a radar waveform and have the potential capability to detect and track different types of ground-moving targets.

Security analysis and enhancements of 3GPP authentication and key agreement protocol

Abstract: This paper analyzes the authentication and key agreement protocol adopted by Universal Mobile Telecommunication System (UMTS), an emerging standard for third-generation (3G) wireless communications. The protocol, known as 3GPP AKA, is based on the security framework in GSM and provides significant enhancement to address and correct real and perceived weaknesses in GSM and other wireless communication systems. In this paper, we first show that the 3GPP AKA protocol is vulnerable to a variant of the so-called false base station attack. The vulnerability allows an adversary to redirect user traffic from one network to another. It also allows an adversary to use authentication vectors corrupted from one network to impersonate all other networks. Moreover, we demonstrate that the use of synchronization between a mobile station and its home network incurs considerable difficulty for the normal operation of 3GPP AKA. To address such security problems in the current 3GPP AKA, we then present a new authentication and key agreement protocol which defeats redirection attack and drastically lowers the impact of network corruption. The protocol, called AP-AKA, also eliminates the need of synchronization between a mobile station and its home network. AP-AKA specifies a sequence of six flows. Dependent on the execution environment, entities in the protocol have the flexibility of adaptively selecting flows for execution, which helps to optimize the efficiency of AP-AKA both in the home network and in foreign networks.

All-digital PLL and GSM/EDGE transmitter in 90nm CMOS

Abstract: A 1.2V 42mA all-digital PLL and polar transmitter for a single-chip GSM/EDGE transceiver is implemented in 90nm CMOS. It transmits GMSK with 0.5/spl deg/ rms phase error and achieves -165dBc/Hz phase noise at 20MHz offset, with 10 /spl mu/s settling time. A digitally controlled 6dBm class-E PA modulates the amplitude and meets the EDGE spectral mask with 3.5% EVM.

Networked Transport of RTCM via Internet Protocol (NTRIP)

Abstract: Within the framework of EUREF, the Federal Agency for Cartography and Geodesy (BKG) has developed a new technique using the open Internet for the real-time collection and exchange of GNSS data, as well as for broadcasting derived products. A major purpose of these activities is the dissemination of Differential GPS corrections (DGPS) for precise positioning and navigation. This paper describes the http-based technique for streaming GNSS data to mobile users connected to the Internet via Mobile IP-Networks like GSM, GPRS, EDGE, or UMTS. The technique establishes a format called Networked Transport of RTCM via Internet Protocol (Ntrip).

Survey of location based wireless services

Abstract: The penetration of mobile wireless technologies has resulted in larger usage of wireless data services in the recent past Several wireless applications are deployed by service providers, to attract and retain their clients, using wireless Internet technologies New and innovative applications like ringtone/wallpaper downloading, MMS-messaging, videoclip delivery and reservation enquiries are some of the popular services offered by the service providers today The knowledge of mobile user's location by the service provider can enhance the class of services and applications that can be offered to the mobile user These class of applications and services, termed "location based services", are becoming popular across all mobile networks like GSM and CDMA This paper presents a brief survey of location based services, the technologies deployed to track the mobile user's location, the accuracy and reliability associated with such measurements, and the network infrastructure elements deployed by the wireless network operators to enable these kinds of services A brief description of all the protocols and interfaces covering the interaction between device, gateway and application layers, are presented The aspects related to billing of value added services using the location information and emerging architectures for incorporating this "location based charging" model are introduced The paper also presents some popular location based services deployed on wireless across the world

Wireless and mobile all-IP networks

Abstract: Acknowledgments. Introduction. 1 Short Message Service and IP Network Integration. 1.1 SMS-IP Integration with SM-SC. 1.2 iSMS System Architecture. 1.3 iSMS Communication Protocols. 1.4 Examples of Services. 1.5 Caching for iSMS-Based Wireless Data Access. 1.6 Concluding Remarks. 1.7 Questions. 2 Mobility Management for GPRS and UMTS. 2.1 Network Architectures. 2.2 Concepts of Mobility Management. 2.3 Mobility Management States. 2.4 MM and PDP Contexts. 2.5 Attach and Detach. 2.6 Location Update. 2.7 Serving RNC Relocation. 2.8 UMTS-GPRS Intersystem Change. 2.9 Concluding Remarks. 2.10 Questions. 3 Session Management for Serving GPRS Support Node. 3.1 Session Management Functions. 3.2 SM Software Architecture. 3.3 SM Software Initiation and Configuration. 3.4 SM Procedures in the SGSN. 3.5 Concluding Remarks. 3.6 Questions. 4 Session Management for Gateway GPRS Support Node. 4.1 APN Allocation. 4.2 IP Address Allocation. 4.3 PDP Context Activation. 4.4 Tunneling between UMTS and External PDN. 4.5 Quality of Service. 4.6 Concluding Remarks. 4.7 Questions. 5 Serving Radio Network Controller Relocation for UMTS. 5.1 SRNC Duplication. 5.2 Core Network Bi-casting. 5.3 Fast SRNC Relocation. 5.4 Comparison of the Relocation Mechanisms. 5.5 Concluding Remarks. 5.6 Questions. 6 UMTS and cdma2000 MobileCore Networks. 6.1 UMTS and cdma2000 Protocol Stacks. 6.2 Mobility and Session Management Mechanisms. 6.3 IP Mobility. 6.4 UMTS and cdma2000 Interworking. 6.5 Concluding Remarks. 6.6 Questions. 7 UMTS Charging Protocol. 7.1 The GTP' Protocol. 7.2 Connection Setup Procedure. 7.3 GTP' CDR Transfer Procedure. 7.4 GTP' Failure Detection. 7.5 Concluding Remarks. 7.6 Questions. 8 Mobile All-IP Network Signaling. 8.1 Signaling System Number 7. 8.2 Stream Control Transmission Protocol (SCTP). 8.3 UMTS Network Signaling. 8.4 UMTS MAP Software Architecture. 8.5 TCAP and SCCP Based on M3UA. 8.6 MAP Message Delivery. 8.7 SCTP and MTP Approaches. 8.8 Concluding Remarks. 8.9 Questions. 9 UMTS Security and Availability Issues. 9.1 Authentication Signaling for UMTS. 9.2 Fraudulent Usage in UMTS. 9.3 Eavesdropping a Mobile User. 9.4 HLR Failure Restoration. 9.5 Concluding Remarks. 9.6 Questions. 10 VoIP for the Non-All-IP Mobile Networks. 10.1 GSM-IP: VoIP Service for GSM. 10.2 vGPRS: VoIP Service for GPRS. 10.3 Concluding Remarks. 10.4 Questions. 11 Multicast for Mobile Multimedia Messaging Service. 11.1 Existing Multicast Mechanisms for Mobile Networks. 11.2 The SMS Multicast Approach III. 11.3 The MMS Multicast Approach IV. 11.4 Concluding Remarks. 11.5 Questions. 12 Session Initiation Protocol. 12.1 An Overview of SIP. 12.2 SIP-based GPRS Push Mechanism. 12.3 SIP-based VoIP Prepaid Mechanism. 12.4 Concluding Remarks. 12.5 Questions. 13 Mobile Number Portability. 13.1 Number Portability for Mobile Telecommunications Networks. 13.2 Call Routing Mechanisms with Number Portability. 13.3 Number Porting and Cost Recovery. 13.4 Concluding Remarks. 13.5 Questions. 14 Integration of WLAN and Cellular Networks. 14.1 The WGSN Approach. 14.2 Implementation of WGSN. 14.3 Attach and Detach. 14.4 WGSN Push Mechanism. 14.5 IEEE 802.1X-based Authentication. 14.6 Concluding Remarks. 14.7 Questions. 15 UMTS All-IP Network. 15.1 All-IP Architecture. 15.2 All-IP Core Network Nodes. 15.3 Registration and Call Control. 15.4 Open Service Access. 15.5 Efficiency of IP Packet Delivery. 15.6 Concluding Remarks. 15.7 Questions. 16 Issues for the IP Multimedia Core Network Subsystem. 16.1 Caching in I-CSCF. 16.2 Integrated Authentication for GPRS and IMS. 16.3 Concluding Remarks. 16.4 Questions. 17 A Proxy-based Mobile Service Platform. 17.1 iProxy Middleware. 17.2 iMobile Service Platform. 17.3 User and Device Management. 17.4 iMobile-based Peer-to-Peer Mobile Computing. 17.5 Concluding Remarks. 17.6 Questions. Bibliography. Index.

Weather station, e.g. consumer weather station, for locally measuring e.g. pressure, has sensor, where station has unit exchanging data with remote server and mobile telephone by using global system for mobile communication type network

Abstract: The station has a sensor (12) e.g. thermometer, measuring temperature. The station has an exchange unit exchanging a data with a remote server (18) and a mobile telephone (50) by using a global system for mobile communication (GSM) type network (20). The station transmits short message service (SMS) type messages, by a data transmission unit (14), during the exchange of the data with the server. The station has a unit (16) receiving the data. The messages have meteorological observations data representing the temperature and data representing date and hour at which measurements are performed.

Clustering and prediction of mobile user routes from cellular data

Abstract: Location-awareness and prediction of future locations is an important problem in pervasive and mobile computing. In cellular systems (e.g., GSM) the serving cell is easily available as an indication of the user location, without any additional hardware or network services. With this location data and other context variables we can determine places that are important to the user, such as work and home. We devise online algorithms that learn routes between important locations and predict the next location when the user is moving. We incrementally build clusters of cell sequences to represent physical routes. Predictions are based on destination probabilities derived from these clusters. Other context variables such as the current time can be integrated into the model. We evaluate the model with real location data, and show that it achieves good prediction accuracy with relatively little memory, making the algorithms suitable for online use in mobile environments.

A digital-to-RF-amplitude converter for GSM/GPRS/EDGE in 90-nm digital CMOS

Abstract: We present the first 90-nm digital CMOS RF power amplifier. This PA contains a large array of NMOS switches, and performs a direct digital-to-RF-amplitude conversion, filtering and buffering in a fully-integrated GSM/EDGE transmitter. Power control is fully digital. 40% efficiency is obtained at 10-dBm output power from 1.4 V and it occupies 0.005 mm/sup 2/.

Multimode/multiband mobile station and method for operating the same

Abstract: A multimode/multiband mobile station and a method for operating the same are provided. A transmission module transmits multimode/multiband signals through transmitters. A reception module receives radio signals for different services of the same frequency band among multimode/multiband signals through receivers for the same frequency band, and receives radio signals of different frequency bands among the multimode/multiband signals through receivers for the different frequency bands. As compared with the conventional mobile station, the multimode/multiband mobile station can reduce the number of receivers by making use of one receiver to receive radio signals for different services of the same frequency band. The multimode/multiband mobile station can use a duplexer of the conventional frequency division duplex (FDD) technique (e.g., wideband code division multiple access (WCDMA)) in a time division duplex (TDD) technique (e.g., Global System for Mobile Communication (GSM) 850 or Personal Communication Service (PCS) 1900).

Multiservice allocation for multiaccess wireless systems

Abstract: This paper discusses principles for allocating multiple bearer services onto different subsystems in multiaccess wireless systems. Based on the included subsystem's multiservice capacities, under certain constraints near-optimum subsystem service allocations that maximize combined multiservice capacity are derived through simple optimization procedures. These favorable service allocations are either extreme points where services, as far as possible, are allocated to the subsystems best at supporting them, or they are characterized by the relative efficiency of supporting services being equal in all subsystems. The consequences of this include that services should typically be mixed in subsystems with convex capacity regions and isolated in subsystems with concave capacity regions. Simple user assignment algorithms based on this are also discussed. Additionally, illustrating the main findings of the analysis, some system examples are given, including a case study with combined global system for mobile communications (GSM) and wideband code-division multiple-access (WCDMA) systems. The gain of using the proposed service allocation principles compared to a reference case of maintaining equal service mixes in all subsystems depends on the shape of the subsystem capacity regions; the more different the capacity regions, the larger the gain. In the GSM and WCDMA case study, capacity gains of up to 100% in terms of supported data users for a fixed voice traffic load are achieved.

Recent advances on TD-SCDMA in China

Abstract: China has fully embraced the remarkable growth and unprecedented penetration of mobile services, and has become the world's largest mobile cellular market. TD-SCDMA was proposed by the China Wireless Technology Standard (CWTS) Group in 1998, approved as one of the 3G standards by ITU in May 2000, and joined 3GPP in March 2001. This has been a major effort by China to advance its mobile communication systems and facilitate its own technological development in this critical area. TD-SCDMA, a combination of TDD and synchronous CDMA, offers several unique advantages over its alternatives, WCDMA and cdma2000, such as flexible spectrum allocation, low-cost implementation, and easier migration from GSM systems. This article reviews the development, key technical features, and deployment of TD-SCDMA in China.

Mobile context inference using low-cost sensors

Abstract: In this paper, we introduce a compact system for fusing location data with data from simple, low-cost, non-location sensors to infer a user's place and situational context. Specifically, the system senses location with a GSM cell phone and a WiFi-enabled mobile device (each running Place Lab), and collects additional sensor data using a 2” x 1” sensor board that contains a set of common sensors (e.g. accelerometers, barometric pressure sensors) and is attached to the mobile device. Our chief contribution is a multi-sensor system design that provides indoor-outdoor location information, and which models the capabilities and form factor of future cell phones. With two basic examples, we demonstrate that even using fairly primitive sensor processing and fusion algorithms we can leverage the synergy between our location and non-location sensors to unlock new possibilities for mobile context inference. We conclude by discussing directions for future work.

Authentication and key agreement protocol for UMTS with low bandwidth consumption

Abstract: Radio interface and wireless service accesses are two areas, in which wireless networks do not provide the same level of protection as wired networks. It may result in the wireless networks being vulnerable to various attacks. For example, the first generation cellular mobile communication systems, such as advanced mobile phone service (AMPS), and the second generation cellular mobile communication systems, such as global system for mobile (GSM), do not take account of security issues comprehensively. It brings about an intruder to be able to eavesdrop user traffic or even change the identities of mobile phones to gain fraudulent services. Therefore, the Universal Mobile Telecommunication System (UMTS), which is known as the third generation (3G) cellular mobile communication system, is proposed. UMTS adopts the security feature of GSM in order to interwork with GSM smoothly. Furthermore, the UMTS adds new security features to design an authentication and key agreement protocol, which is called UMTS AKA protocol. However, it is found that the UMTS AKA has some problems, including bandwidth consumption between a serving network and a user's home network, space overhead of the serving network and sequence number synchronization. Therefore, in this paper, we propose an extension of UMTS AKA protocol, called UMTS X-AKA to overcome the aforementioned problems of UMTS AKA.

Mobile location estimation based on differences of signal attenuations for GSM systems

Abstract: GSM system provides measurements regarding the signal attenuations from serving and neighboring base stations for managing radio resources. This paper proposes a mobile location estimation based on differences of downlink signal attenuations, which yield circles along which the mobile may lie. Then, the curves intersect at the estimated mobile position. The proposed method does not require a known and accurate path loss modeling, reduces the impact of shadowing on location, and is capable of being applied in existing systems without hardware development. Performance simulations include environments involving different standard deviation and cross-correlation of shadowings, and different abilities to detect base stations. Simulations demonstrate encouraging performance with only three base stations being available in severe shadowing environments. Additionally, the results of driving measurement show that the proposed method outperforms the cell-ID method in a real GSM in urban Taipei.

Validation of an improved location-based handover algorithm using GSM measurement data

Abstract: When a mobile station moves, the path loss and shadow fading contribute to the large-scale variation in the received signal strength. The variation of signal strength caused by shadow fadings is a random process, and handover decision mechanisms based on measurements of signal strength induce the "ping-pong effect." This paper proposes an improved handover algorithm, based on the estimates of location and velocity of the mobile station, to suppress the ping-pong effect in cellular systems. A practical approach based on GSM measurement data is used to estimate the location and velocity of mobile station to identify the correlation among shadowing components. The impact of location errors on handover performance was examined, and the proposed handover algorithm was applied to a real GSM system in urban Taipei city. The results indicate that the number of unnecessary handover can be reduced 18-26 percent by the proposed approach compared to the conventional method, while the signal outage probability remains similar. Besides, the computational complexity of the proposed algorithm is low, and the algorithm does not use a database or lookup table.

Efficient gap allocation for cell measurements in asynchronous communication networks

Abstract: Techniques for allocating transmission gaps and making cell measurements in asynchronous communication networks are described. A terminal establishes communication with a first communication network (e.g., a W-CDMA network), receives an initial allocation of transmission gaps for making cell measurements, and makes measurements for cells in a second communication network (e.g., a GSM network) during the allocated transmission gaps. The terminal determines the timing of at least one cell in the second network, which is asynchronous with the first network, and sends the cell timing to the first network. The terminal then receives a new allocation of transmission gaps for making cell measurements. The locations of the transmission gaps in the new allocation are determined based on the cell timing reported by the terminal. The terminal makes measurements for the at least one cell in the second network during the transmission gaps in the new allocation.

System for automated diagnosis in cellular networks based on performance indicators

Abstract: This paper presents a system for automated diagnosis of problems in a cellular network, which comprises a method and a model. The reasoning method, based on a naive Bayesian classifier, can be applied to the identification of the fault cause in GSM/GPRS, 3G or multi-systems networks. A diagnosis model for GSM/GPRS radio access networks is also described, whose elements are available in the network management systems (NMSs) of most networks. It is shown that the statistical relations among the elements, that is the quantitative part of the model, under certain assumptions, can be completely specified by means of the parameters of beta density functions. In order to support the theoretical concepts, a model has been built based on data from a real network and the automated diagnosis system has been used to classify problems in a cellular network, showing that the solution is easily implemented and that the diagnosis accuracy is very high, therefore leading to a reduction in the operational costs of running the network. Copyright © 2005 AEIT.

A discrete time quad-band GSM/GPRS receiver in a 90nm digital CMOS process

Abstract: We present the receiver in the first single-chip GSM transceiver that incorporates full integration of quad-band receiver, transmitter, memory, power management, dedicated ARM processor and RF built-in self test in a 90 nm digital CMOS process. The architecture uses direct RF sampling in the receiver and an all-digital PLL in the transmitter. The receive chain uses discrete-time analog signal processing to down convert, down- sample, filter and analog-to-digital convert the received signal. An auxiliary feedback is provided at the mixer output that can linearize the entire receive chain. The receiver meets a sensitivity of -110 dBm at 60 mA in a 1.4V digital CMOS process

Front-end topology for multiband multimode communication engines

Abstract: The combination of filters and switches is used to solve the non-linearity problems in GSM/W-CDMA transceiver front-end wherein one common antenna is used for both the GSM mode and the W-CDMA mode In particular, separate Rx/Tx paths and switches in the Rx paths are used to provide cross-band isolation between bands All of the switches in the transceiver are disposed after the filters in that no switches are disposed between the filters and the antenna Furthermore, bandpass filters are matched to one common node even if they are only disconnected at the output as long as the impedance at the output can be controlled

Security in a mobile communications system

Abstract: When a mobile terminal (10), having a basic identity module (12) operative according to a first security standard, initiates a service access, the home network (30) determines whether the mobile terminal has an executable program (14) configured to interact with the basic identity module for emulating an identity module according to the second security standard. If it is concluded that the mobile terminal has such an executable program, a security algorithm is executed at the home network (30) to provide security data according to the second security standard. At least part of these security data are then transferred, transparently to a visited network (20), to the mobile terminal (10). On the mobile terminal side, the executable program (14) is executed for emulating an identity module according to the second security standard using at least part of the transferred security data as input. Preferably, the first security standard corresponds to a 2G standard, basically the GSM standard and the second security standard at least in part corresponds to a 3G standard such as the UMTS standard, and/or the IP Multimedia Sub-system (IMS) standard.

Method for rerouting mobile phone communications

Abstract: The invention relates to a method for rerouting mobile phone communications involving a GSM phone provided with a Subscriber Identification Module (SIM) allowing TCP/IP connection, which method provides for TCP/IP connection to a dedicated central server comprising a plurality of SIM's corresponding to different GSM networks, and that the method provides for the emulation of an image of a selected SIM to the GSM phone or a dedicated cooperating separate device, as a virtual SIM, in addition to the actual SIM provided in the GSM phone, from information provided by said central server. The invention also specifically relates to a dedicated device for cooperating with a GSM phone in such a method.

Taxi service safety and dispatching monitor system

Abstract: The invention is a taxi operation safety and dispatching control system consisting of vehicle device, GSM/GPRS or 3G mobile communication platform, road traffic information module, calling module, preserving and calling module, passenger position identifying module, monitor module, geographic information module, safety module, guide module, charging module and so on. The system sends the passenger on and off information into dispatching center and records vehicle coordinate and line to dispatching center data base.

Optimizing Web delivery over wireless links: design, implementation, and experiences

Abstract: World over wide-area wireless Global System for Mobile Communication (GSM) networks have been upgraded to support the general packet radio service (GPRS). GPRS brings "always-on" wireless data connectivity at bandwidths comparable to that of conventional fixed-line telephone modems. Unfortunately many users have found the reality to be rather different, experiencing very disappointing performance when, for example, browsing the Web over GPRS. In This work, we show what causes the web and its underlying transport protocol TCP to underperform in a GPRS wide-area wireless environment. We examine why certain GPRS network characteristics interact badly with TCP to yield problems such as: link underutilization for short-lived flows, excess queueing for long-lived flows, ACK compression, poor loss recovery, and gross unfairness between competing flows. We also show that many Web browsers tend to be overly aggressive, and by opening too many simultaneous TCP connections can aggravate matters. We present the design and implementation of a web optimizing proxy system called GPRSWeb that mitigates many of the GPRS link-related performance problems with a simple software update to a mobile device. The update is a link-aware middleware (a local "client proxy") that sits in the mobile device, and communicates with a "server proxy" located at the other end of the wireless link, close to the wired-wireless border. The dual-proxy architecture collectively implements a number of key enhancements-an aggressive caching scheme that employs content-based hash keying to improve hit rates for dynamic content, a preemptive push of Web page support resources to mobile clients, resource adaptation to suit client capabilities, delta encoded data transfer of modified pages, DNS lookup migration, and a UDP-based reliable transport protocol that is specifically optimized for use over GPRS. We show that these enhancements results in significant improvement in web performance over GPRS links.

The Simulation of Realistic Acoustic Input Scenarios for Speech Recognition Systems

Abstract: A tool for simulating the acoustic conditions during the speech input to a recognition system and the transmission in telephone networks is presented in this paper. The simulation covers the hands-free speech input in rooms and the existence of noise in the background. Furthermore the presence of telephone frequency characteristics can be simulated. Finally the transmission in a cellular telephone system like GSM or UMTS is covered including the encoding and decoding of speech and the transmission over the erroneous radio channel. The tool has been realized by integrating functions from the ITU software library for implementing telephone frequency characteristics and the estimation of the speech level as well as software modules from ETSI and 3GPP for the AMR encoding and decoding of speech. A Web interface has been designed to experience the simulation tool with acoustic examples.