Proposals on UMTS system configuration

In the project FRAMES (Future Radio Wideband Multiple Access Systems) of the European research program ACTS (Advanced Communications Technologies and Services) an air interface proposal for UMTS (Universal Mobile Telecommunications System) has been developed. In January 1998 ETSI (European Telecommunications Standards Institute) reached a consensus on a UMTS air interface standard termed UTRA (UMTS Terrestrial Radio Access), which is mainly based on the proposal developed within FRAMES. UTRA consists of an FDD (frequency division duplex) mode applying the multiple access scheme W-CDMA (wideband CDMA) and a TDD (time division duplex) mode applying the multiple access scheme TD-CDMA (time division CDMA). For the different services to be supported a set of channel coders has been proposed which have to be further evaluated. In consideration of this need, in this paper a low-complexity rate-compatible punctured turbo code (RCPTC) for high-quality circuit switched data services in the TDD-mode is investigated depending on its main parameters. The criterion in these investigations is the bit error ratio (BER). The performance of the considered turbo code (TC) is analyzed and compared to a convolutional code (CC) of equal complexity.

CSELT (Telecom Italia group research centre), TIM (Telecom Italia Mobile) and Ericsson have set up an experimental testbed for the evaluation of UMTS (Universal Mobile Telecommunications System). The aim of the trial, carried out at the CSELT premises in Turin, is to study the characteristics of the system, as far as the radio and network aspects are concerned, with reference to some UMTS services. In particular, several trials have been focused on the multimedia applications that the system enables by means of its packet switched service (IP over ATM connections) and circuit switched connections (IP over point-to-point protocol connections). New multimedia services, that can not be delivered with today's second generation mobile radio systems, have been evaluated thanks to the high bit rate available on the radio interface (up to 472.6 kbps with the experimental equipment).

IntroductionThe popularity of mobile communication systems has increased remarkably during the last decade and the market demand still continues to increase.As a fundamental part of these systems, antenna is one of the most important design issues in modern mobile communication units.Although there are several similar definitions, an antenna can be mainly described as a device, which transforms the electromagnetic waves in an antenna to radiating waves in an unbounded medium such as air in transmitting mode and vice versa in receiving mode.Because antennas are dependent on frequency, they are designed to operate for certain frequency bands.The rapid growth of mobile communication systems has forced to the use of novel antennas for base and mobile station applications (mobile phone, notebook computer, personal digital assistants (PDA), etc.).Earlier, mobile systems were designed to operate for one of the frequency bands of 2G (second generation) systems, which are Digital Cellular System (DCS), Personal Communications Service (PCS) and Global System for Mobile Communications (GSM) networks.Currently, many mobile communication systems use several frequency bands such as GSM 900/1800/1900 bands (890-960 MHz and 1710-1990 MHz); Universal Mobile Telecommunication Systems (UMTS) and UMTS 3G expansion bands (1900-2200 MHz and 2500-2700 MHz); and Wi-Fi (Wireless Fidelity)/Wireless Local Area Networks (WLAN) bands (2400-2500 MHz and 5100-5800 MHz) where the list of frequently used frequency bands is given in Table 1 ( Best, 2008).Conventionally, because a single antenna can not operate at all of these frequency bands of mobile communication, multiple different antennas covering these bands separately should be used.However, usage of many antennas is usually limited by the volume and cost constraints of the applications.Therefore, multiband and wideband antennas are essential to provide multifunctional operations for mobile communication.A multiband antenna in a mobile communication system can be defined as the antenna operating at distinct frequency bands, but not at the intermediate frequencies between bands.For example, a triple band antenna for GSM 900/1800/1900 bands can cover the frequency bands 890-960 MHz and 1710-1990 MHz (Ali et al., 2003); however, it does not operate properly at the frequencies such as 1200 MHz or 2500 MHz.On the other hand, a wideband antenna operates at every frequency points within a given frequency band.For example, a wideband antenna covering UMTS, extended UMTS and WLAN 2400 bands functions at every frequency points www.intechopen.com

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.

In the third generation of mobile systems several satellite systems are expected to be integrated with the terrestrial cellular network. A number of roles of satellites have been defined within third generation of mobile systems, for example, providing UNITS (universal mobile telecommunication systems) services in area lacking in terrestrial facilities, providing services to aeronautical users etc. This paper deals with the requirement of reducing the cost of call delivery to roamers within the satellite based mobile systems. We consider both mobile originated and PSTN originated calls to be optimally routed to roamers. For reducing the cost of PSTN originated calls, the notion of a roamer location (RLR) is introduced, which maintains the information of all the roamers within the country. On the other hand for routing mobile originated calls optimally, caller is asked to register at the MSC which is nearest to the called subscriber's PSTN or PLMN switch, so as to minimize the usage of the network trunks. The biggest advantage of the proposed scheme is that it is simple to implement and all the calls from the visited country results in a local call.

The Universal Mobile Telecommunication System (UMTS) adopts WCDMA as the air interface that provides variable transmission rate services. Four traffic classes are identified in UMTS, given as controversial, streaming, interactive, and background classes. To efficiently utilize the radio bandwidth, the shared channel technology is proposed to deliver interactive and background traffics. This paper proposes a shared-channel assignment and scheduling (SCAS) algorithm to allocate shared channels to interactive and background connections. We formally prove that the SCAS algorithm can satisfy the transmission rate requirement of each interactive connection and can efficiently utilize the radio bandwidth.

The rapid evolution of 3G technology demands an adaptive, robust network management system. In the 3G UMTS (Universal Mobile Telecommunications System) system, a new radio access network (RAN) called UTRAN (UMTS terrestrial radio access network) is introduced based on W-CDMA (instead of TDMA/FDMA) air interface transmission. The normal network management functionality needs to be supported that is, fault configuration, accounting, performance and security management (FCAPS). The network resource model for UMTS is defined by 3GPP [1] and is object oriented Output data for bulk configuration has a standard XML format defined by the 3GPP. By applying standard software engineering techniques for exporting XML from a relational database we demonstrate that using a relational database for storing management data can achieve very good performance for bulk configuration management export.

This paper discusses about feasibility of common wireless communication services recognition concept for three different standards, i.e. global system for mobile communications (GSM), universal mobile telecommunications system (UMTS) or wideband code division multiple access (WCDMA), and long term evolution (LTE). They are in mobile telecommunication field also known well as 2G, 3G, and 3.9G respectively. In the term of cognitive system to recognize these three standard services, we investigate the initialization procedure and downlink signal structure as an important keys. As a result, there is big possibility to develop a common wireless communication services recognition for GSM, UMTS and LTE through a concept of synchronization channel detection.

Third-generation mobile radio networks, often dubbed as 3G, have been under intense research and discussion recently and will emerge around the year 2000. In the International Telecommunications Union (ITU), third generation networks are called International Mobile Telecommunications-2000 (IMT-2000), and in Europe, Universal Mobile Telecommunications System (UMTS). IMT-2000 will provide a multitude of services, especially multimedia and high-bit-rate packet data. Wideband code division multiple access (CDMA) has emerged as the mainstream air interface solution for the third-generation networks. In Europe, Japan, Korea, and the United States, wideband CDMA systems are currently being standarized. This article provides a comprehensive introduction to wideband CDMA. It also provides a review of the wideband CDMA air interface proposals including WCDMA in Europe and Japan, cdma2000 in the United States, and wideband CDMA in Korea.

The third-generation IMT-2000 initiative of the International Telecommunication Union is aiming at the provision of a limited family of global standards providing worldwide multimedia wireless services in a host of environments encompassing indoor picocells to satellite megacells. The ITU IMT-2000 initiative has been supported by several regional standardization bodies such as the European Telecommunication Standard Institute with its Universal Mobile Telecommunication System. In this article a few air interface proposals for the satellite component of UMTS/IMT-2000 based on adaptation of the emerging terrestrial wideband CDMA standards are reviewed. In particular, S-UMTS requirements are examined together with W-CDMA applicability to the satellite environment. It is shown that with minor adaptations, the terrestrial W-CDMA air interface provides an efficient solution for the satellite UMTS component. This commonality will certainly help in the realization of low-cost low-size dual-mode user terminals encompassing both terrestrial and satellite components.

Release99 of UMTS (universal mobile telecommunication system) network supports conversational services by means of UTRAN (universal terrestrial radio access network) dedicated transport channels (DCH). In this paper we evaluate by means of dynamic simulations the impacts of the radio access network on the end-to-end quality of service (QoS) of voice over IP (VoIP). In order to characterize the QoS level, an analytical model devoted to predict the mean opinion score (MOS) has been considered. Finally, an investigation of the most proper set-up of the service is also presented, taking into account inter-layer parameters such as the dimension of the VoIP client buffer as well as the block error rate at the air interface (BLER).

Despite the fact that the third generation (3G) mobile system is expected to provide a wide range of services, including data access, it has been designed primarily for voice services and it provides QoS guarantee in terms of bit rate and delay. These QoS metrics are more suitable for a real time streaming service rather than the dominant data service in the Internet. The paper proposes new QoS metrics, and response time, for Internet data access in the Universal Mobile Telecommunication System (UMTS). The new metrics reflect the user's expectation of QoS. Networks can change delay and bit rate according to the current situation while keeping the response time constant. A proxy based architecture is presented to support the new QoS guarantee. The proxy caches files and helps the wireless network to schedule file transfer according to the system capacity and user demand. Theoretical analysis and simulation show that the new scheme can improve user-level performance and network utilization.

5G mobile communication networks are emerging in order to cover the extreme needs for high data rates for delivering multimedia data to mobile communication users. The required bandwidth may be found if millimeter wave bands are fully employed for the establishment of such cellular systems. In this Book Chapter the propagation issues for 5G mobile communication systems are rigorously analyzed and presented. Firstly, the most popular scenarios and architectures of the next generation mobile systems are described and the channel models utilized for the evaluation of physical layer techniques (air interface are given. Secondly, the channel effects are described, i.e. effects due to local environment of the transceivers, atmospheric effects and their combination and the state of the art on the modeling of these effects is analytically presented. Finally, future directions for the propagation and channel model prediction for the next generation mobile communication systems -5G millimeter wave cellular systems are analyzed. Open issues and technical challenges of millimeter wave (mmWave) 5G cellular systems are finally described.

The provision of high speed packet data services in an efficient way is probably the most important challenge for the Universal Mobile Telecommunications System (UMTS) since this can give an advantage over second generation systems. The efficiency depends mainly on the radio interface due to its great flexibility. It is of utmost importance to investigate the effect of different configurations on the system performance. In this paper we evaluate the performance of packet data services over downlink dedicated channels (DCH) by means of detailed simulations. Due to the traffic variability, Automatic Repeat reQuest (ARQ) mechanism and closed loop power control the system behavior is quite complex and not so easily predictable as with constant rate services such as voice. We study the effect of several parameters (spreading factor, code rate, channel setup delay, etc.) on the system capacity by means of the delay-throughput curves. We show that the setting of parameters may be critical for system capacity and stability. For this reason we propose a flow control mechanism which is able to guarantee stability and enable the system capacity to be almost independent of channel rates.

Telecom operators' proliferation, caused by the liberation in the provision of communication services in the European domain, has led in the emergence of demand for small, cost effective core network elements capable of performing both access communication, as well as, traffic routing towards various technology backbones. Bulky equipment is no longer attracting operators' interest, for a number of reasons, summarized in downsize ability (monolithic support of millions of users on a single box is not the case anymore for start up operators), scalability and flexibility to seamlessly integrate advanced services. Especially in the case of UMTS, IP communications are realized over a mixture of heterogeneous transportation technologies often resulting to replication of redundant functions, which limits network performance, complicates its maintenance, reduces scalability and increases operational costs. This paper presents a flexible gateway architecture, which can be accommodated on the access interfaces of UMTS networks to enable realization of generic communication interfaces towards core network databases, supporting user access and traffic routing functions, for improved IP communications performance, enhances UMTS network scalability and reduces maintenance costs. Architectural modularity is achieved by integrating the various database technologies within a common network architecture utilising Storage Area Networks technology.