Mobile Multimedia Services Research Articles

Determinants of adoption of third generation mobile multimedia services

In this article, we review user information technology acceptance literature, formulate a model of consumer adoption of third generation mobile multimedia services, validate it through a qualitative exploratory study comprising 24 focus groups in six markets, and empirically test the proposed model on the Italian market. The results show that perceived usefulness, ease of use, price, and speed of use are the most important determinants of adoption of multimedia mobile services, in that order. They also show that the importance of determinants differs by age groups or segments. The results can help managers proactively design interventions (such as training and marketing activities) targeted at populations of users that may be less inclined to adopt and use new multimedia mobile services.

Preference‐based session management for IP‐based mobile multimedia signaling

AbstractThe increasing variety of mobile multimedia services raises the need for mechanisms to select those services whose capabilities best match individual user requirements. In this paper, we present an advanced concept for service personalization in next‐generation IP‐based mobile systems based on the notion of user preferences. The described concept features several enhancements for personalization, including the intuitive modeling of user preferences, the construction of complex preference terms from basic preference expressions and a stepwise refinement of profiles and preferences. We describe this solution applied to the signaling mechanism of the Session Initiation Protocol (SIP), which is the protocol suite for application control in current IP‐based mobile communication systems such as UMTS. In particular, our preference concept for personalized service management extends the conventional SIP preference modeling methods proposed so far: a preference order on the available service features is introduced that accounts for the specific demands of a user without a numerical ranking of features. We show how base preferences can be intuitively combined to complex preference expressions and explain how these relate to standard SIP feature preferences. Copyright © 2004 AEI

A Framework for MPEG-4 Contents Delivery over DMB

Digital Multimedia Broadcasting (DMB) is an upcoming standard in Korea used to provide mobile multimedia broadcasting service based on the Eureka-147 Digital Audio Broadcasting (DAB) system. The current dominant multimedia coding standard, MPEG-4, is foreseen to play an important role in forthcoming DMB services. However, the current approaches for transporting MPEG-4 content over DMB networks are not optimized. To address this issue we propose a novel MPEG-4 stream multiplexer, called M4SMux, which provides better stream multiplexing and delivery over DMB networks. M4SMux features an MPEG-4 elementary-stream interleaving mechanism that reduces the multiplexing overhead and a multiplex configuration mechanism that utilizes M4SLinkTable for easy content access. In addition, we propose an error correction method which enhances transport efficiency.

PROSPECTS FOR MOBILE COMMUNICATION SYSTEMS AND KEY TECHNOLOGIES CAPABLE OF SUPPORTING EXPANDING MOBILE MULTIMEDIA SERVICES

The first commercial service of the 3rd generation (3G) mobile communication system, IMT-2000 (International Mobile Telecommunications), was launched in October 2001 in Japan. This is the first 3G service employing Wideband Code Division Multiple Access (W-CDMA) as its air interface between mobile terminals and base stations. This new system, 3G, is expected to accelerate the deployment of future mobile multimedia services, which substantially got started with the "i-mode" service in February 1999 in Japan. Research activities into future mobile communication systems capable of supporting a vastly expanded market for mobile multimedia services are underway worldwide. This paper describes the vision, service trends, and technical challenges of such future systems. Broadband packet wireless access, Variable Spreading Factor Orthogonal Frequency and Code Division Multiplexing (VSF-OFCDM), are promising candidates for realizing future mobile communication systems that provide higher transmission rates and capacity than 3G systems.

System for enhanced network management jointly exploiting WLANs and other wireless network infrastructures

Mobile multimedia services are expected to be in high demand from mobile wireless users on a worldwide scale. The research community and telecommunications industry have focused their efforts in providing suitable wireless networks for such services. The great advance achieved among wireless local area network (WLAN) technologies, combined with the current delays in deploying 3 G cellular networks, forces the network operators to investigate possible interworking mechanisms to exploit the broadband capabilities of WLANs jointly with currently deployed 2.5 G cellular networks, as well as other commercial broadband systems. The authors present a generic management platform, suitable for WLANs interworking with other wireless systems, targeting the implementation of a high-speed wireless environment and able to maintain multimedia services, especially at hot-spot locations. The main aim was to keep the functional layout of each individual wireless network as close as possible to its original form. Finally, the authors present examples of WLANs interworking with other wireless systems, using either real commercially deployed networks or laboratory testbeds.

Mobile next-generation networks

Mobile next-generation networks (NGNs) are a necessary element in reaching the goal of truly ubiquitous computing. The Universal Mobile Telecommunication System, the third-generation mobile service concept, is a technology step to mobile NGNs. We can view NGNs as a merger of the Internet and intranets with mobile networks and with media and broadcast technologies. The Universal Mobile Telecommunication System (UMTS) is-from a radio perspective-a third-generation cellular technology, which is defined by the International Telecommunication Union (ITU) in its IMT-2000 framework (2001). From a conceptual point of view, it represents a technology step to mobile NGNs' facilitating ubiquitous computing. Researchers conceived UMTS to combine Internet protocol (IP) and mobile technologies to offer personal communication and personalized content everywhere. Its goal is to apply Internet protocols for mobile services control and end-to-end applications. By analyzing the trends of key technologies, we can see how they drive the evolution of the Internet and mobile communications toward mobile NGNs. In this article, I describe the IP-based approach of UMTS for the provision of mobile multimedia services. The integration of WLAN into the UMTS architecture could indicate that the field is moving toward separating mobile and fixed Internet.

A perspective an the evolution of mobile communications

This article outlines the current state of mobile communications and presents some of the future directions in research and development from the perspective of NTT DoCoMo with special emphasis on the market in Japan. It first describes the directions in which mobile communications are expected to forge ahead in the future, and the service implementation strategies they could employ. Then it describes an example of mobile multimedia services and present an outline of the Freedom of Mobile Multimedia Access (FOMA), which is a service based on the 3G mobile communications system called International Mobile Telecommunications-2000 (IMT2000). This is followed by an overview of our R&D approach to 4G systems, which constitute mobile communications systems of the future, and the profile of technologies to make these happen. Finally, it reviews our approach to future technologies that are expected to be realized in 4G and subsequent systems, and illustrate it with an example of a research project.

Adaptive QoS for wireless multimedia networks using power control and smart antennas

This paper addresses the problem of adaptive quality-of-service (QoS) for mobile multimedia services under a power controlled wireless network using smart antennas. Given the nature of multimedia, we chose the signal-to-interference-and-noise ratio (SINR) of each user's channel as the QoS index. We direct our attention toward two problems. The first is to increase the SINR levels for multimedia users as much as the system can provide for, under channel fading and interference conditions. Different users have distinct desired SINR levels according to their requested service types; our algorithm uses an iterative method to drive the SINR levels as close as possible to those desired levels. The SINR levels are improved without deteriorating quality for other types of users. Simulations show a significant increase in the average SINR levels for multimedia users. The second problem considered is how to initiate new users into the network speedily by using lower complexity algorithms that yield reliable results. Simulations show that our fast activation scheme can substantially reduce the time for activating new users into the system.

Third-generation mobile telecommunications and virtual home environment: A prioritization analysis

The International Telecommunication Union (ITU) is currently setting standards for the third-generation International Mobile Telecommunication 2000 (IMT-2000) system. This system offers its users mobile multimedia services with a global roaming capability. This capability allows IMT-2000 users to invoke the services they have subscribed to with their home network service provider anywhere around the globe in a manner transparent to them. The requirements for global roaming relate to three distinct functional capabilities of the network: mobility management, call/connection control, and service transportability. In this paper we address the role service transportability plays in offering the virtual home environment (VHE) to IMT-2000 users. To achieve the IMT-2000 global roaming capability, service transportability combines the concept of the Intelligent Network's distributed functional plane (DFP) across different IMT-2000 systems with a number of VHE implementation scenarios. We describe the IMT-2000 system and its various VHE implementation scenarios, evaluate those scenarios, and prioritize their deployment with respect to criteria such as location of service control, location of service database, point of service invocation, and required standardization effort.

The present and future of mobile multimedia services(<Special feature>Mobil environment and Information)

The present and future of mobile multimedia services(<Special feature>Mobil environment and Information)

Smart antennas for UTRA TDD

AbstractDue to the increasing number of users in mobile communications and the demand for mobile multimedia services with high data rates, third generation mobile radio systems are currently one of the key communication technologies in research, development, and international standardization bodies. Smart antennas can be used to increase the capacity of wireless communication systems even further. TDD systems are particularly attractive for the employment of smart antennas, since the channel information (e. g., in terms of spatial covariance matrices) estimated on the uplink can be used directly for downlink beamforming. In this paper, we discuss efficient uplink and downlink processing techniques with smart antennas for UTRA TDD, the TDD mode of third generation mobile radio systems that is based on TD—CDMA. On the uplink, joint space—time processing is used to eliminate co—channel interference created by other users that transmit on the same frequency and in the same time slot. These joint detection techniques are efficiently implemented in the frequency domain. On the downlink, the data is only transmitted in the direction of the desired mobile user while interference in the direction of co—channel users is avoided. Moreover, short—term spatial channel estimates can be improved by projecting them into the dominant subspace of the long—term spatial covariance matrix. System level simulations have been performed to evaluate the gain in spectral efficiency (available bit rate per bandwidth per cell) if simple downlink beamforming techniques are used at the base stations. There is a two— to three—fold spectral efficiency gain if antenna arrays of M = 8 elements are deployed in a sectorized macro—cellular environment.

Propagation considerations and fading countermeasures for mobile multimedia services

AbstractThis paper presents a summary of land mobile satellite (LMS) channel characteristics derived from several measurement campaigns. Narrowband and wideband measurements allow a broad interpretation of the LMS channels. Channel models and its parameters have been derived from the measured data as well. Furthermore, the impact of the LMS channel on the communication service is investigated and possible countermeasures are discussed. Link margins, power control schemes and satellite diversity can compensate the fading on the transmission links. The benefit of adaptive receivers and the dependence on the signal bandwidth are investigated, too. Copyright © 2001 John Wiley & Sons, Ltd.

Convergence of cellular and broadcast networks from a multi-radio perspective

The demand of both the new telecom industry and digital broadcasters for cost-efficient provisioning of mobile multimedia services faces the reality of scarce radio resources. Various digital mobile and broadcast radio technologies have been developed and specifically been optimized. However, existing and emerging multimedia services exhibit challenging requirements in terms of asymmetry, interactivity, real time, and multicast communication. This article describes an evolution of an IP-based infrastructure from today's networks toward a future multi-radio infrastructure, taking into account the implications on the end-user terminal. This multi-radio infrastructure enables the cooperation of existing radio networks to combine their spectrum-efficient capabilities, whereby high-quality mobile multimedia services shall be provided. Furthermore, the need for dynamic allocation of spectrum to radio services is motivated. The basic functionality and architecture of a multi-radio system are outlined, with a special emphasis on cooperation between different radio systems. Also, an evolution path for the convergence of broadcast and new telecom is described, starting from today's systems and leading to a fully coordinated system.

Convergence of Broadcast and New Telecom Networks

The demand of the new telecom industry for cost efficient provision of mobile multimedia services is faced with the reality of scarce radio resources. The requirement of spectrum efficiency has driven the development of various digital radio technologies that have been optimized for specific services, namely for broadcast or for mobile communication. However, existing and emerging multimedia services exhibit challenging requirements in terms of asymmetry, interactivity, real-time, and multicast communication. This paper describes an IP based multi-radio infrastructure that enables the co-operation of existing radio networks to combine their capabilities to ensure a spectrum efficient provision of high-quality mobile multimedia services. Further the need for a dynamic allocation of spectrum to radio services is motivated. The basic functionality and the architecture of a multi-radio system is outlined, with a special emphasis on the cooperation between different radio systems. Further an evolution path for the convergence of broadcast and new telecom is desribed, starting from today's systems and leading to a fully coordinated system.

Development for 4th generation mobile communications

The great success of the i-mode service shows that data communication services are becoming accepted in the mobile communication world. Multimedia mobile communication services will be provided by 3rd generation IMT-2000 systems next year in Japan. Thus, the time has come to begin the research and development for 4th generation (4G) mobile communication systems. There exist many difficult issues for 4G systems, such as frequency resources, additional investment, higher speed wireless transmission technology and so on. Furthermore, a new concept must be discussed for 4G before solving these issues. This paper briefly presents current conditions of cellular systems and the development of IMT-2000 in Japan. The concept and problems of the 4G system are then described along with new technologies that will be useful in solving technical problems. Copyright © 2001 John Wiley & Sons, Ltd.

Three generations of cellular wireless systems

Advances in cellular communication technology have resulted in improved capacity, higher data rates and better quality of service (QoS). Many first and second-generation systems have been deployed and currently offer a range of predominantly voice-oriented services. Third generation cellular systems have been proposed with the goal of providing a seamless integration of mobile multimedia services into a single global network infrastructure. These systems are all summarized in a table.

Modelling mobile multimedia services

Future multimedia and Internet services will have more complex characteristics than the traditional service types. Accurate planning of mobile networks requires accurate prediction of traffic flows, which involves complex relationships between the services themselves, the mobility of users, and the business environment. This paper describes the work of the Mobile VCE services programme on new traffic models that take all three factors into account.

A study of global multimedia mobile satellite communication system: Current status

In Japan, Next-generation LEO System (NeLS) research center was established with a support of the Ministry of Posts and Telecommunications (MPT) in the end of 1997. This research center focuses on a study for the LEO system called NeLS which would provide global multimedia mobile satellite services. The target services include up to 2 Mbps multimedia data transmission using handheld or portable terminals. The target year for operation is 2010. This paper describes the current status of technical development of the NeLS project, in terms of satellite constellation, optical inter-satellite link (ISL), satellite antenna, user link, and satellite network.

Time slot allocation in CDMA/TDD systems for mobile multimedia services

An important issue in wireless multimedia communications is to cope with the traffic asymmetry between uplink and downlink. The asymmetrical slot allocation in the code division multiple-access systems with time-division duplex mode (CDMA/TDD systems) can be a good solution for this problem. However, the level of traffic asymmetry can be significantly different from cell to cell. In this letter, we calculate the utilization of a CDMA/TDD system for the multicell model. In addition, we suggest an optimal slot allocation that maximizes the frequency utilization.

The complete solution for third-generation wireless communications: two modes on air, one winning strategy

Due to the increasing number of users in mobile communications and the demand for mobile multimedia services with high data rates, third-generation mobile radio systems are currently one of the key communication technologies in research, development, and international standardization bodies. This article summarizes the international standardization activities for this new technology, outlines its key applications, and provides an overview of UMTS as specified by the 3GPP. Moreover, an overview of capacity-enhancing features such as joint (multi-user) detection and smart antennas is given. Finally, we develop a vision for mobile communications beyond the third generation.