Multimedia Data Transfer Research Articles

Optimum Threshold for Velocity Considered-SINR Based Vertical Handoff Decision in HetNet

A heterogeneous network (HetNet) that consists of various wireless networks is being massively studied. Integration of the networks should be error free to achieve seamless communication. The seamless vertical handoff (VHO) remains a challenging problem in HetNet studies. Several criteria for VHO decision have been studied in the literature, such as Received Signal Strength (RSS) and Signal to Interference plus Noise Ratio (SINR). It has been shown that SINR based VHO has superior performance compare to RSS based VHO. However, there are some limitations in SINR based VHO scheme. This study aims to overcome those limitations by considering user velocity as an additional criterion for SINR based VHO decision. User velocity is represented in the value of additional SINR threshold. The basic principle of the proposed algorithm is that slow speed user should stay longer in WLAN cells and high speed user should stay longer in WCDMA cells. Simulation results show that there is a trade-off between average throughput and the number of unnecessary handoffs per call. In this study, optimum threshold is obtained when the high percentage of unnecessary handoffs reduction is reached with an acceptable value of average throughput for multimedia data transfer.

Realtime Multimedia Data Transfer Mechanism in Heterogeneous Monitoring Systems

Realtime Multimedia Data Transfer Mechanism in Heterogeneous Monitoring Systems

Implementation of the UMTS technology for improving of capacity and reliability of data transfer in wireless network

The implementation of the UMTS technology in wireless mobile networks for improving of capacity and reliability is considered. Standard methodologies application for enhancing of ability of modern mobile devices of multimedia data transfer are analyzed. The main differences between the structure of the system of 3G UMTS and standard 2G GSM are highlighted

Design and Implementation of Multilevel Access Control in Synchronized Audio to Audio Steganography Using Symmetric Polynomial Scheme

Steganography techniques are used in Multimedia data transfer to prevent adversaries from eaves dropping. Synchronized audio to audio steganography deals with recording the secret audio, hiding it in another audio file and subsequently sending to multiple receivers. This paper proposes a Multilevel Access control in Synchronized audio steganography, so that Audio files which are meant for the users of low level class can be listened by higher level users, whereas the vice-versa is not allowed. To provide multilevel access control, symmetric polynomial based scheme is used. The steganography scheme makes it possible to hide the audio in different bit locations of host media without inviting suspicion. The Secret file is embedded in a cover media with a key. At the receiving end the key can be derived by all the classes which are higher in the hierarchy using symmetric polynomial and the audio file is played. The system is implemented and found to be secure, fast and scalable. Simulation results show that the system is dynamic in nature and allows any type of hierarchy. The proposed approach is better even during frequent member joins and leaves. The computation cost is reduced as the same algorithm is used for key computation and descendant key derivation. Steganography technique used in this paper does not use the conventional LSB’s and uses two bit positions and the hidden data occurs only from a frame which is dictated by the key that is used. Hence the quality of stego data is improved.

A mobile multimedia satellite system reusing existing satellites

AbstractSince 2001, the European Space Agency has investigated a file‐based system for providing satellite radio to the automotive market. This system is significantly different from existing commercial counterparts, such as the American systems XM‐radio and Sirius. In terms of service it not only provides traditional radio services but is also capable of offering multimedia content and data transfer. In terms of infrastructure, it does not require launch of new satellites or deployment of terrestrial repeaters. As such it offers a highly efficient, low‐investment and low‐risk approach to offering satellite radio services to a consumer automotive market. Moreover, it departs from the traditional schedule‐based streaming radio concept to a concept in line with the concurrent developments within the media landscape, providing the user the full control of what entertainment to play and when to play it. This paper presents the system in more detail, outlines its performance and makes comparisons with other existing satellite radio systems. Copyright © 2008 John Wiley & Sons, Ltd.

WISTA: A Wireless Telemedicine System for Disaster Patient Care

In this paper, we introduce a low-cost and easy-to-deploy wireless telemedicine system, denoted WISTA, that can assist on-site patient care during disasters. The proposed system facilitates real-time transfer of multimedia data from video cameras, sensors, medical images and text from multiple disaster sites to the control center of the disaster area. WISTA enables disaster managers to obtain patients' status information in real-time from the entire disaster site, which can assist the timely diagnosis as well as the treatment of patients. Moreover, the disaster managers in the control center can remotely control the information sent from the individual disaster sites. The proposed system uses a hierarchical architecture which allows scalable implementation. For dense disaster areas, a layered structure is applied to support information dissemination from s large number of patients. We have implemented the system prototype over a wireless channel and successfully demonstrated simultaneous transmission of video, sensor information, medical images and text from multiple sites to the control center. In addition, the scalability of the system is evaluated using OPNET simulation. Both experiments validate our system design.

Proactive Web caching with cumulative prefetching for large multimedia data

Web proxy caching provides an effective way to reduce access latency and bandwidth consumption, and thus improve performance of the World Wide Web. Due to the simplicity of incorporating various types of data into the Web, non-negligible access for large multimedia data is observed. Large multimedia data transfer, requiring a long-lived connection with consecutive data transmissions, often fails over wide area networks. Repetitive attempts to fetch large objects through proxy caches would waste network resources with no success guaranteed. In this paper, we propose on-demand cumulative prefetching to enhance proxy caches for better data availability of large multimedia files. Our analysis shows that on-demand cumulative prefetching can be performed within a few trials with minimal additional bandwidth requirement. The experimental results demonstrate that the proposed scheme substantially reduces error rate and increases byte hit rate for large multimedia data.

A software reconfigurable satellite communication/navigation transceiver ASIC

In this paper, a software reconfigurable W-CDMA transceiver ASIC called CDMAxTM for 3G mobile satellite applications is presented. A maximum chip rate of 20 Mchips/s is possible, allowing upto 2 Mbit/s multimedia data transfers. The use of reconfigurable hardware, together with the adoption of a specific parameter-independent clocking strategy allows the combination of multi-standard operation together with a low power consumption. The CDMAxTM ASIC combines several 3G satellite air interfaces together with satellite navigation reception capabilities, and has the necessary flexibility to be future-proof for possible changes in the air interface standards. Copyright © 2000 John Wiley & Sons, Ltd.

Distributed algorithms for the constrained routing problem in computer networks

The quickest path problem is possibly the most important problem for data routing in computer networks. The quickest path problem is to find quickest paths in a computer network to transmit a given amount of data with minimal transmission time. The selection of quickest paths depends on both the characteristics of the computer network and the amount of data to be transmitted. In addition, if the quickest paths are required to go through a specified path, then the restricted problem is called the constrained quickest path problem. In this study, some new distributed routing algorithms are developed for multimedia data transfer in an asynchronous computer network. For all pairs of nodes in a network, an O( mn) messages and O( m) time distributed algorithm is first presented to find constrained quickest paths, and then an O( mn) messages and O( m) time distributed algorithm is present to enumerate the first k quickest paths.

Toward Wireless Multimedia Communications. Current Standards and Future Directions

There are two major trends in communicationstechnology: multimedia and mobile communications. Thisis necessary to support new service concepts anddemanding capabilities of wireless communicationsystems. Although the migration to ATM-based broadbandISDN is visible, wireless ATM (WATM) internetworking formobile clients is still in its infancy. In this article,a brief overview of the current mobile communications standards GSM and DECT is presented. It isshown why these standards fail to deliver adequateperformance for multimedia data transfer. We thendescribe the recently approved IEEE 802.11 wirelesslocal area network standards and ETSI HIPERLAN 1 indetail and discuss their suitability for the transfer ofATM cells. Next, the ongoing work of the ATM Forum'sWATM Working Group and the efforts of the ETSI RES 10 regarding the further development ofHIPERLAN 2, 3, and 4 is elaborated. Finally, severalexisting WATMs are described.

The expressive task specification and adaptive image data handling for mobile applications

An efficient multimedia data handling is a fundamental requirement of mobile multimedia applications. To accommodate this requirement, issues of the available technologies as well as mobile multimedia data access and transfer processes, and the characteristics of the medium to be handled should all be taken into consideration. For this end, these aspects are investigated. The results of the investigation lead to the conclusion that an expressive task specification and adaptive multimedia data handling should be provided. With an expressive task specification, a demand for accessing multimedia object can be described flexibly to enable a minimum handling overhead (thus high performance) and an optimal compromise between performance, cost and quality. Adaptive media handling functionality adapts the service performance according to the medium to be accessed, the available resources and compromise preference of a mobile client, etc. This paper presents the new concepts and methods for these two aspects.

Distributing broadband multimedia systems using CORBA

This paper proposes that the Channel Provider, a generic communication platform developed by the RACE II project EuroBridge, could be integrated with CORBA, thus enabling the ORB to provide real-time bindings and QoS control and negotiation between objects for the transfer of multimedia data. The requirements placed on CORBA by multimedia applications are addressed, and the EuroBridge Channel Provider's (CP) ability to satisfy these requirements is outlined. The complementary nature of these architectures is discussed by investigating the relationships between them and the impact that manipulation of the OMA object model has on the CP control interface. Finally, a description of the process of integrating the EuroBridge Channel Provider and Orbix, a full implementation of CORBA, is given, and conclusions drawn.

Partial order connections : a new concept for high speed and multimedia services and protocols

This paper presents a new concept that has been developed to define high performance multimedia data transfers between communicating entities. All current protocols use either connectionless (Cl) or connection-oriented (Co) approaches and many mechanisms have been proposed in each case. Both sets of present Cl and co protocols are not conceptually related and there is a design gap between the definition and use of these two families. A new concept, a partial order connection (Poc), is defined here. It will be seen that Cl and Co approaches are two specific cases of the much more general concept presented here. More precisely, a Poc is an end-to-end connection that provides a partial order service where the objects can be delivered to the users in a different order from the transmitted order. It is first shown how this new concept has emerged and what are its interests in terms of resources. Then a formal definition of reliable and unreliable Pocs and a way to measure their complexity will be given. It is shown how such a generalized connection can be used and how time constraints can be handled in an integrated way, leading to the definition of a design space for protocols.