Showing papers on "GSM published in 2008"

Redpin - adaptive, zero-configuration indoor localization through user collaboration

Abstract: Redpin is a fingerprint-based indoor localization system designed and built to run on mobile phones. The basic principles of our system are based on known systems like Place Lab or Radar. However, with Redpin it is possible to consider the signal-strength of GSM, Bluetooth, and WiFi access points on a mobile phone. Moreover, we devised methods to omit the time-consuming training phase and instead incorporate a folksonomy-like approach where the users train the system while using it. Finally, this approach also enables the system to expeditiously adapt to changes in the environment, caused for example by replaced access points.

Ambient RF Energy Scavenging: GSM and WLAN Power Density Measurements

Abstract: To assess the feasibility of ambient RF energy scavenging, a survey of expected power density levels distant from GSM-900 and GSM-1800 base stations has been conducted and power density measurements have been performed in a WLAN environment. It appears that for distances ranging from 25 m to 100 m from a GSM base station, power density levels ranging from 0.1 mW/m2 to 3.0 mW/m2 may be expected. First measurements in a WLAN environment indicate even lower power density values, making GSM and WLAN unlikely to produce enough ambient RF energy for wirelessly powering miniature sensors. A single GSM telephone however has proven to deliver enough energy for wirelessly powering small applications on moderate distances.

Evolved Packet System (EPS): The LTE and SAE Evolution of 3G UMTS

Abstract: 2G/GSM and 3G/UMTS are key mobile communication technologies, chosen by more than 2 billion people around the world. In order to adapt to new services, increasing demand for user bandwidth, quality of service and requirements for network convergence, major evolutions are introduced in 3G network standard. Evolved Packet System (EPS) presents the EPS evolution of the 3G/UMTS standard introduced by the 3rd Generation Partnership Project (3GPP) standard committee. This new topic is looked at from a system perspective, from the radio interface to network and service architecture. Hundreds of documents being issued by Standard organisations are summarised in one book to allow the reader to get an accessible comprehensive view of EPS evolution. Proposes a system view of Evolved UMTS, from the radio to Core and service architecture Gives a comprehensive and global view of the system that technical specifications do not provide Describes the new system as well as the inheritance and migration from 2G/GSM and 3G/UMTS Written by experts in the field who specialise in two complementary but very different technical domains (i.e. "radio interface" and "network architecture") Contains many figures and examples for better understanding. This book is essential for industry professionals in the telecommunication business, telecommunication system architects and designers, product manufacturers and operators and postgraduate students.

Automated Diagnosis for UMTS Networks Using Bayesian Network Approach

Abstract: This paper presents an automated diagnosis in troubleshooting (TS) for Universal Mobile Telecommunications System (UMTS) networks using a Bayesian network (BN) approach. An automated diagnosis model is first described using the Naive Bayesian Classifier. To increase the performance of the diagnosis model, the entropy minimization discretization (EMD) method is incorporated into the model to select optimal segments for the discretization of the input symptoms. In the first phase, the diagnosis model is constructed using a dynamic simulator. The simulator TS platform allows generation of a large amount of data required to study the relations between faults and symptoms. In the second phase, the diagnosis model is adapted to a real UMTS network using counters and key performance indicators (KPIs) recovered from an Operations and Maintenance Center (OMC). Results for the automated diagnosis using both network simulator and real UMTS network measurements illustrate the efficiency of the proposed TS approach and its importance to mobile network operators.

Instant Ciphertext-Only Cryptanalysis of GSM Encrypted Communication

Abstract: In this paper we present a very practical ciphertext-only cryptanalysis of GSM (Global System for Mobile communications) encrypted communication, and various active attacks on the GSM protocols. These attacks can even break into GSM networks that use “unbreakable” ciphers. We first describe a ciphertext-only attack on A5/2 that requires a few dozen milliseconds of encrypted off-the-air cellular conversation and finds the correct key in less than a second on a personal computer. We extend this attack to a (more complex) ciphertext-only attack on A5/1. We then describe new (active) attacks on the protocols of networks that use A5/1, A5/3, or even GPRS (General Packet Radio Service). These attacks exploit flaws in the GSM protocols, and they work whenever the mobile phone supports a weak cipher such as A5/2. We emphasize that these attacks are on the protocols, and are thus applicable whenever the cellular phone supports a weak cipher, for example, they are also applicable for attacking A5/3 networks using the cryptanalysis of A5/1. Unlike previous attacks on GSM that require unrealistic information, like long known-plaintext periods, our attacks are very practical and do not require any knowledge of the content of the conversation. Furthermore, we describe how to fortify the attacks to withstand reception errors. As a result, our attacks allow attackers to tap conversations and decrypt them either in real-time, or at any later time. We present several attack scenarios such as call hijacking, altering of data messages and call theft.

Cost-Function-Based Network Selection Strategy in Integrated Wireless and Mobile Networks

Abstract: Wireless and mobile networks have experienced great success over the past few years. However, any single type of wireless and mobile network cannot provide all types of services, e.g., wide coverage and high bandwidth. An integrated wireless and mobile network is introduced by combining these different types of wireless and mobile networks, which can provide more comprehensive services. In an integrated wireless and mobile network, a mobile terminal that is equipped with heterogeneous network interfaces is capable of accessing all the available networks. Therefore, how to select a desired network is an important issue for the integrated wireless and mobile network. Although some network-selection strategies have been proposed, most of them are designed to meet a user's individual needs, such as the bandwidth, the access fee, or the power consumption. The system performance also has not been touched. In this paper, we propose a cost-function-based network selection (CFNS) strategy in an integrated wireless and mobile network from a system's perspective, which also considers a user's needs. We also analyze the system performance of the proposed network-selection strategy by using a theoretical model and extensive simulations. The results obtained show that the proposed network-selection strategy affects multiple system parameters, which needs to be handled carefully.

Access methods to WiMAX femtocells: A downlink system-level case study

Abstract: Over the last two years, GSM and UMTS femtocell access points have been proposed as a solution to the poor indoor coverage problem experienced in certain areas. Research on these devices has shown that femtocells will not only increase indoor system coverage, but also system capacity. Femtocells will allow new services and business models to be offered to indoor users. Almost parallely, the WiMAX standard has emerged as a potential candidate technology for the future wireless networks. WiMAX femtocells are currently under development and will therefore play an important role in the world of indoor broadband wireless access. However, several aspects of this new technology, such as the access method and interference avoidance techniques play a crucial role in the amount of interference caused to co-channel deployed macrocells. This paper provides a framework for the study of WiMAX macro-femtocell hybrid scenarios. An in-depth description of the necessary radio coverage prediction and system-level simulation for this kind of scenarios is introduced. Simulations and numerical results for two different types of access methods (public and private) in the downlink are also presented.

Handover from e-utran to utran/geran cs

Abstract: The present invention relates to a method for a handover of a UE (User Equipment) currently engaged in a voice call. More particularly, the invention relates to a handover from 1) a packet based radio where Voice Service is provided via VoIP over the radio and is controlled via Session Initiation Protocol (SIP) based signalling (e.g. LTE, E-UTRAN or WIMAX radio) to 2) a radio access network where Voice Service can be only provided via circuit switched (CS) domain (a visited mobile switching centre (VMSC) is needed) such as legacy 3GPP UMTS Terrestrial Radio Access Network (UTRAN)/ GSM/Edge Radio Access Network (GERAN) coverage. A MSC-S entity acting as a Packet Core Control Node on a Packet Switched (PS) network and as an Anchor Visited Mobile Switching Centre (VMSC) for a handover to a Circuit Switched (CS) network on the CS domain side is proposed, the MSC-S preparing a new path with a remote UE-B and a CS domain handover towards a target legacy radio coverage before requesting a UE- A to execute the handover.

A Novel Approach for Joint Radio Resource Management Based on Fuzzy Neural Methodology

Abstract: In this paper, an innovative mechanism to perform joint radio resource management (JRRM) in the context of heterogeneous radio access networks is introduced. In particular, a fuzzy neural algorithm that is able to ensure certain quality-of-service (QoS) constraints in a multicell scenario deployment with three different radio access technologies (RATs), namely, the wireless local area network (WLAN), the universal mobile telecommunication system (UMTS), and the global system for mobile communications (GSM)/Enhanced Data rates for GSM Evolution (EDGE) radio access network (GERAN), is discussed. The proposed fuzzy neural JRRM algorithm is able to jointly manage the common available radio resources operating in two steps. The first step selects a suitable combination of cells built around the three available RATs, while the second step chooses the most appropriate RAT to which a user should be attached. A proper granted bit rate is also selected for each user in the second step. Different implementations are presented and compared, showing that the envisaged fuzzy neural methodology framework, which is able to cope with the complexities and uncertainties of heterogeneous scenarios, could be a promising choice. Furthermore, simulation results show that the reinforcement learning mechanisms introduced in the proposed JRRM methodology allow guaranteeing the QoS requirement in terms of the so-called user dissatisfaction probability in the presence of different traffic loads and under different dynamic situations. Also, the proposed framework is able to take into consideration different operator policies as well as different subjective criteria by means of a multiple decision-making mechanism, such as balancing the traffic among the RATs or giving more priority to the selection of one RAT in front of another one.

Characterization of personal RF electromagnetic field exposure and actual absorption for the general public.

Abstract: In this paper, personal electromagnetic field exposure of the general public due to 12 different radiofrequency sources is characterized. Twenty-eight different realistic exposure scenarios based upon time, environment, activity, and location have been defined and a relevant number of measurements were performed with a personal exposure meter. Indoor exposure in office environments can be higher than outdoor exposure: 95th percentiles of field values due to WiFi ranged from 0.36 to 0.58 V m(-1), and for DECT values of 0.33 V m(-1) were measured. The downlink signals of GSM and DCS caused the highest outdoor exposures up to 0.52 V m(-1). The highest total field exposure occurred for mobile scenarios (inside a train or bus) from uplink signals of GSM and DCS (e.g., mobile phones) due to changing environmental conditions, handovers, and higher required transmitted signals from mobile phones due to penetration through windows while moving. A method to relate the exposure to the actual whole-body absorption in the human body is proposed. An application is shown where the actual absorption in a human body model due to a GSM downlink signal is determined. Fiftieth, 95th, and 99 th percentiles of the whole-body specific absorption rate (SAR) due to this GSM signal of 0.58 microW kg(-1), 2.08 microW kg(-1), and 5.01 microW kg(-1) are obtained for a 95th percentile of 0.26 V m(-1). A practical usable function is proposed for the relation between the whole-body SAR and the electric fields. The methodology of this paper enables epidemiological studies to make an analysis in combination with both electric field and actual whole-body SAR values and to compare exposure with basic restrictions.

A Markovian Approach to Radio Access Technology Selection in Heterogeneous Multiaccess/Multiservice Wireless Networks

Abstract: This paper addresses the problem of radio access technology (RAT) selection in heterogeneous multi-access/multi-service scenarios. For such purpose, a Markov model is proposed to compare the performance of various RAT selection policies within these scenarios. The novelty of the approach resides in the embedded definition of the aforementioned RAT selection policies within the Markov chain. In addition, the model also considers the constraints imposed by those users with terminals that only support a subset of all the available RATs (i.e. multi-mode terminal capabilities). Furthermore, several performance metrics may be measured to evaluate the behaviour of the proposed RAT selection policies under varying offered traffic conditions. In order to illustrate the validation and suitability of the proposed model, some examples of operative radio access networks are provided, including the GSM/EDGE Radio Access Network (GERAN) and the UMTS Radio Access Network (UTRAN), as well as several service-based, load-balancing and terminal-driven RAT selection strategies. The flexibility exhibited by the presented model enables to extend these RAT selection policies to others responding to diverse criteria. The model is successfully validated by means of comparing the Markov model results with those of system-level simulations.

Design and Implementation of Remote Monitoring System Based on GSM

Abstract: Because the wireless remote monitoring system has more and more application, a remote monitoring system based on SMS of GSM is presented. Based on the total design of the system, the hardware and software of the system is designed. In this system, GSM network is a medium for transmitting the remote signal. The system includes two parts which are the monitoring center and the remote monitoring station. The monitoring center consists of a computer and a TC35 communication module of GSM. The computer and TC35 are connected by RS232. The remote monitoring station includes a TC35 communication module of GSM, a MSP430F149 MCU, a display unit, various sensors, data gathering and processing unit. The software of the monitoring center and the remote monitoring station is designed by using VB. The result of demonstration shows that the system can monitor and control the remote communication between the monitoring center and the remote monitoring station, and the remote monitoring function is realized.

SSMS - A secure SMS messaging protocol for the m-payment systems

Abstract: The GSM network with the greatest worldwide number of users, succumbs to several security vulnerabilities. The short message service (SMS) is one of its superior and well-tried services with a global availability in the GSM networks. The main contribution of this paper is to introduce a new secure application layer protocol, called SSMS, to efficiently embed the desired security attributes in the SMS messages to be used as a secure bearer in the m-payment systems. SSMS efficiently embeds the confidentiality, integrity, authentication, and non-repudiation in the SMS messages. It provides an elliptic curve-based public key solution that uses public keys for the secret key establishment of a symmetric encryption. It also provides the attributes of public verification and forward secrecy. It efficiently makes the SMS messaging suitable for the m-payment applications where the security is the great concern.

TCP Wake-Up: Reducing Keep-Alive Traffic in Mobile IPv4 and IPsec NAT Traversal

Abstract: Applications such as instant messaging and push email require long-lived connections between clients and servers. In the absence of other traffic, stateful firewalls and Network Address Translators (NATs) require “keep-alive” messages to maintain state for such persistent connections. We present new measurements analyzing the energy consumption of these keep-alive messages on a mobile phone in 2G (GSM), 3G (WCDMA), High-Speed Downlink Packet Access (HSDPA), and IEEE 802.11 Wireless LAN networks. The measurements confirm earlier results showing that frequent keep-alive messages consume significant amounts of energy in 2G and 3G networks, but suggest they are not a significant problem in Wireless LANs. To reduce energy consumption, we introduce TCP Wake-Up, an extension to Mobile IPv4 and IPsec NAT traversal mechanisms. This extension significantly reduces the need for keep-alive messages, while still avoiding complexity of IP-over-TCP tunneling. Our measurements show that TCP Wake-Up can extend battery lifetime by a factor of 2 to 7 in 2G/3G networks. The results also suggest guidelines for developers of future protocols: in particular, we claim that “always-on” applications that aim to be used in current 2G/3G networks cannot be solely based on UDP.

Mapping uplink acknowledgement transmission based on downlink virtual resource blocks

Abstract: An acknowledgment (ACK) mapping automation that reduces overhead for a wireless communication systems such as UTRAN-LTE, Global System for Mobile communications (GSM: originally from Groupe Special Mobile), High-Speed Downlink Packet Access (HSDPA), or any packet-switched system, by providing a mapping of uplink (UL) location (ie, modulation location in time, frequency, and code) based upon a downlink (DL) allocations Aspects address dynamic and persistent scheduling of user equipment (EU) with a selected combination of implicit and explicit mapping

Parsimonious Mobility Classification using GSM and WiFi Traces

Abstract: Human mobility states, such as dwelling, walking or driving, are a valuable primary and meta data type for transportation studies, urban planning, health monitoring and epidemiology. Previous work focuses on fine-grained location-based mobility inference using global positioning system (GPS) data and external geo-indexes such as map information. GPS-based mobility characterization raises practical issues related to spotty coverage and battery drain, but the more fundamental concern addressed in this paper is that of privacy. For some applications and usage models we contend that it is desirable to adopt a more parsimonious approach to mobility characterization; one that avoids the collection and use of fine-grained location information by relying instead on GSM and WiFi connectivity data. Building upon previous work that demonstrated the utility of using GSM and WiFi beacons for localization applications, we demonstrate that this approach to mobility classification achieves promising results (with accuracy of 88%) using a sample data set collected across several populated areas in Los Angeles and is worthy of further research.

A 45nm 3.5G Baseband-and-Multimedia Application Processor using Adaptive Body-Bias and Ultra-Low-Power Techniques

Abstract: System on Chip (SoC) integration is the theme of the first integrated 3.5G baseband and multimedia applications processor fabricated using a low-power digital and analog design platform and 45nm process technology. This SoC supports mobile standards: HSUPA/HSDPA, WCDMA, EDGE/GPRS/GSM and applications such as MPEG-4 video streaming, Java and MP3 audio. The high- performance multimedia, multiprocessor engine includes an 840MHz ARM1176, a 480MHz TMS320C55x DSP, and a 240MHz image processor.

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on event related potentials and cognitive functions

Abstract: Modern mobile phones emit electromagnetic fields (EMF) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. Until now most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies have focused on Universal Mobile Telecommunications System (UMTS)-EMF. Therefore, we tested the effects of both types of unilaterally presented EMF, 1950 UMTS (0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on visually evoked occipital P100, the P300 of a continuous performance test, auditory evoked central N100 and the P300 during an oddball task as well as on the respective behavioral parameters, reaction time and false reactions, in 15 healthy, right handed subjects. A double-blind, randomized, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users. Bioelectromagnetics 29:488–497, 2008. © 2008 Wiley-Liss, Inc.

Method and apparatus to confirm mobile equipment has remained relatively stationary using one or more pilot signal

Abstract: A tracking unit operably coupled to mobile equipment is provided. The tracking unit is capable of using a pilot channel for CDMA networks, a broadcast channel for GSM networks or the like, to determine that the tracking unit has remained relatively stationary. The tracking unit determines it has remained relatively stationary by determining that it is receiving the same radio frequency signals at approximately the same strength as it previously received.

A 50MHz bandwidth multi-mode PA supply modulator for GSM, EDGE and UMTS application

Abstract: This paper describes the design and measurement results of a supply modulator for a PA for GSM, EDGE and UMTS application. The modulator combines a high-bandwidth class-AB linear regulator with an efficient DC/DC converter in a master-slave configuration. The DC/DC converter is current-mode controlled and has been designed to operate at switching frequencies between 1 MHz and 25 MHz. A damped dual-inductor LCR filter has been inserted in the output branch of the DC/DC converter for ripple suppression. The chip has been fabricated in a 0.25 mum CMOS process with an additional gate oxide for 6 V transistors and has an active area of 1.5 mm2. It achieves a bandwidth of 50 MHz (for UMTS) with a peak output power of 3.2 W (for GSM) and output rms ripple of less than 4 mV.

A Data Modem for GSM Voice Channel

Abstract: This paper introduces a novel approach to data communication over the global system for mobile communications (GSM) voice channel. It is based on the concept of ldquosymbolsrdquo-a set of predefined signals with finite bandwidths. Data are encoded into the symbols, and the symbols are voice coded as they were speech, modulated into the GSM signal, sent over the air, GSM demodulated, voice decoded, and converted back to data. The symbols are synthesized by a genetic algorithm with the aim of maintaining separability after passing them through the voice codec. This method enables data transfer over communication networks that do not have dedicated data channels and could also be used in conjunction with other data services to balance the system load between data and voice channels, allowing optimization of system resources. We present the full algorithmic structure of the system, which performs data communications over the GSM voice channel, and we also give the results of the performance tests.

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on well-being and resting EEG.

Abstract: Modern mobile phones emit electromagnetic fields (EMFs) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. To date most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies were concerned with Universal Mobile Telecommunications System (UMTS)-EMF. Consequently, we tested the effects of both types of EMF, 1950 MHz UMTS (SAR 0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on well-being and vigilance-controlled resting electroencephalogram (eyes closed) in 15 healthy, right-handed subjects. A double-blind, randomised, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.

System for determining real time network up time

Abstract: The inventive system and method for determining the availability of a computer network comprises a device operable to connect to at least the computer network using internet communications and using GSM, and an alarm service and/or a central server, wherein the device attempts to connect to the computer network using the internet communications and if the device fails to connect within a predetermined value, such as an amount of time or a number of tries, the device uses the GSM to notify the alarm service of the failure to connect. In one embodiment, after the device notifies the alarm service and/or central server of the failure to connect, the device continues to attempt to connect to the computer network, and if the device connects within another predetermined value, the device notifies the alarm service and/or central server of the restoral of service.

Indoor Radio Planning: A Practical Guide for GSM, DCS, UMTS and HSPA

Abstract: Mobile wireless applications are a good way to increase productivity, improve customer service and streamline business processes. 3G mobile applications, however, bring a unique challenge: ensuring adequate in-building coverage. Indoor Radio Planning provides an overview of mobile networks systems and coverage solutions for cellular networks in buildings. The background of GSM, UMTS and HSPA cellular systems technology are presented and form the backdrop of the main discussion as to why indoor coverage is needed and how it is best implemented. Basic passive distributed antenna systems (DAS) through to advanced fiber optic systems are discussed in detail, giving the reader a good understanding of all the available solutions. In addition, there is a section covering multi-operator systems, as this is becoming a more and more utilized approach. Other sections cover aspects such as how to upgrade passive DAS from 2G to 3G, noise analysis, link budgets, traffic calculations and software tools that can be used to provide help with creating in-building designs. These topics are examined at length from the basic considerations to advanced indoor radio planning. One of the first texts dedicated solely to indoor radio planning, it will be of essential reading to engineering and planning personnel working for mobile operators, with the book being written with radio planners in mind throughout. Indoor Radio Planning will also be of interest to companies who service and manufacture equipment for operators such as suppliers of indoor coverage systems and vendors of base stations for mobile coverage. A unique, single-source reference for both the theoretical and practical knowledge behind indoor radio planning Written by a leading practitioner in the field with more than 15 years of experience Based on real life examples and implemented systems and results Analyzes co-existence of mobile services and inter modulation analysis Outlines the key parameters and metrics for designing DAS for GSM, DCS, UMTS and HSPA

Balanced SiGe PA Module for Multi-Band and Multi-Mode Cellular-Phone Applications

Abstract: In this paper, the integration of a MM (GSM/EDGE/WCDMA) MB (850/900MHz, 1800/1900/2100MHz) 50 Omega-matched isolator-less flip-chip PAs, capable of envelope and power tracking operation, is discussed. The PAs are integrated in a 0.25 mum SiGe technology and are soldered on a 4-layer substrate. The system is hosted in a 6 x 8 mm2 plastic module.

Mobile Device Analysis

Abstract: —The increased usage and proliferation of small scaledigital devices, like celluar (mobile) phones has led to theemergence of mobile device analysis tools and techniques. Thisfield of digital forensics has grown out of the mainstream practiceof computer forensics. Practitioners are faced with various typesof cellular phone generation technologies, proprietary embeddedfirmware systems, along with a staggering amount of uniquecable connectors for different models of phones within the samemanufacturer brand.This purpose of this paper is to provide foundational conceptsfor the data forensic practitioner. It will outline the commoncell phone technologies, their characteristics, and device han-dling procedures. Further data evidence storage areas are alsoexplained along with data types found in the various storageareas. Specific information is also noted about BlackBerry andiPhone devices.Detailed procedures for data analysis/extraction for mobiledevices and how to use the various toolkits that are availableis beyond the scope of this paper; the staggering numbers of cellphones and the intricacies of the toolkits makes this impossible.However, resources for the reader to further investigate the topicare attached in the appendix.Index Terms—Mobile Device, Cell Phones, BlackBerry, PDA,Smart Phones, Cellular Phone Generation, CDMA, TDMA,GSM, iDen, SIM, IMEI, IMSI, ICCID, ESN, MEID, PIN, PUK,Flash Memory, Memory Cards, Mobile Device Analysis, AnalysisTools, Cell Phone Forensics

Innovative design of a planar fractal‐shaped GPS/GSM/Wi‐Fi antenna

Abstract: In this letter, the design of a microstrip three-band antenna working in GPS, GSM and Wi-Fi frequency bands is described. By considering a planar geometry printed on a dielectric substrate, the tuning of the antenna behavior in three non-harmonic frequency bands is obtained perturbing the patch perimeter according to a Koch-like fractal shape. The synthesis procedure is automatically performed by means of an iterative PSO-based optimization strategy where a fractal boundary generator is integrated with a MoM-based electromagnetic simulator. The feasibility of the approach as well as the reliability of the synthesized antenna is assessed through simulations as well as experimental results. The definitive version is available at www3.interscience.wiley.com

New research in nature inspired algorithms for mobility management in GSM networks

Abstract: Mobile Location Management (MLM) is an important and complex telecommunication problem found in mobile cellular GSM networks. Basically, this problem consists in optimizing the number and location of paging cells to find the lowest location management cost. There is a need to develop techniques capable of operating with this complexity and used to solve a wide range of location management scenarios. Nature inspired algorithms are useful in this context since they have proved to be able to manage large combinatorial search spaces efficiently. The aim of this study is to assess the performance of two different nature inspired algorithms when tackling this problem. The first technique is a recent version of Particle Swarm Optimization based on geometric ideas. This approach is customized for the MLM problem by using the concept of Hamming spaces. The second algorithm consists of a combination of the Hopfield Neural Network coupled with a Ball Dropping technique. The location management cost of a network is embedded into the parameters of the Hopfield Neural Network. Both algorithms are evaluated and compared using a series of test instances based on realistic scenarios. The results are very encouraging for current applications, and show that the proposed techniques outperform existing methods in the literature.

Vulnerabilities of UMTS Access Domain Security Architecture

Abstract: This paper presents vulnerabilities of UMTS access domain security architecture. The security architecture of UMTS offers some protection against known threats including false base station attacks, man-in-the-middle attacks and replay attacks. The system also successfully ensures user data confidentiality and signaling data integrity. However, a few novel vulnerabilities have been identified in this paper. It has been shown that modification of unprotected initial messages prior to the security mode command may result in DoS and man-in-the-middle attacks. Non-integrity protection of rrcConnectionReject message can also be exploited to launch DoS attack. Clear transmission of IMSI on some occasions is a violation of user identity/location confidentiality and user traceability. This exposed IMSI can be exploited for new attacks.