31,361 research outputs found
Lessons learned from the design of a mobile multimedia system in the Moby Dick project
Recent advances in wireless networking technology and the exponential development of semiconductor technology have engendered a new paradigm of computing, called personal mobile computing or ubiquitous computing. This offers a vision of the future with a much richer and more exciting set of architecture research challenges than extrapolations of the current desktop architectures. In particular, these devices will have limited battery resources, will handle diverse data types, and will operate in environments that are insecure, dynamic and which vary significantly in time and location. The research performed in the MOBY DICK project is about designing such a mobile multimedia system. This paper discusses the approach made in the MOBY DICK project to solve some of these problems, discusses its contributions, and accesses what was learned from the project
IEEE Transactions on Broadcasting Special Issue on: 5G for Broadband Multimedia Systems and Broadcasting
[EN] The upcoming fifth-generation ( 5G ) of wireless communications technologies is expected to revolutionize society digital transformation thanks to its unprecedented wireless performance capabilities, providing speeds of several Gbps, very low latencies well below 5 ms, ultra-reliable transmissions with up to 99.999% success probability, while being able to handle a huge number of devices simultaneously connected to the network. The first version of the 3GPP specification (i.e., Release 15) has been recently completed and many 5G trials are under plan or carrying out worldwide, with the first commercial deployments happening in 2019."© 2019 IEEE. Personal use of this material is permitted. PermissĂon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisĂng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."Gomez-Barquero, D.; Li, W.; Fuentes, M.; Xiong, J.; Araniti, G.; Akamine, C.; Wang, J. (2019). IEEE Transactions on Broadcasting Special Issue on: 5G for Broadband Multimedia Systems and Broadcasting. IEEE Transactions on Broadcasting. 65(2):351-355. https://doi.org/10.1109/TBC.2019.2914866S35135565
The Design of a System Architecture for Mobile Multimedia Computers
This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies
IPv6 mobility support for real-time multimedia communications: A survey
Mobile Internet protocol version 6(MIPv6) route optimization improves triangular routing problem that exists in MIPv4 environment.Route optimization of Session Initiation Protocol (SIP) over MIPv6 provides efïżœcient real-time multimedia applications to users. This article provides a survey of SIP over MIPv6. We review the processes involved during the setting up of a SIP call and during mid-call SIP mobility. When SIP transmits real-time multimedia applications in a wireless environment, the mobile node (MN) may move from one access router (AR) to
another AR, handing over control from one AR to the other. High handover latency degrades the quality of real-time multimedia applications due to the fact that real-time multimedia applications are delay-sensitive.Handover latency is an important issue to discuss.Reduction of handover latency can be made possible with the use of SIP's hierarchical registration. On the other hand, hybrid hierarchical and fast handover SIP's registration performs better compared to hierarchical registration. Finally, we present the directions for future research
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A connection-level call admission control using genetic algorithm for MultiClass multimedia services in wireless networks
Call admission control in a wireless cell in a personal communication system (PCS) can be modeled as an M/M/C/C queuing system with m classes of users. Semi-Markov Decision Process (SMDP) can be used to optimize channel utilization with upper bounds on handoff blocking probabilities as Quality of Service constraints. However, this method is too time-consuming and therefore it fails when state space and action space are large. In this paper, we apply a genetic algorithm approach to address the situation when the SMDP approach fails. We code call admission control decisions as binary strings, where a value of â1â in the position i (i=1,âŠm) of a decision string stands for the decision of accepting a call in class-i; a value of â0â in the position i of the decision string stands for the decision of rejecting a call in class-i. The coded binary strings are feed into the genetic algorithm, and the resulting binary strings are founded to be near optimal call admission control decisions. Simulation results from the genetic algorithm are compared with the optimal solutions obtained from linear programming for the SMDP approach. The results reveal that the genetic algorithm approximates the optimal approach very well with less complexity
Energy-efficient wireless communication
In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters
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Distributed video coding in wireless multimedia sensor network for multimedia broadcasting
Recently the development of Distributed Video Coding (DVC) has provided the promising theory
support to realize the infrastructure of Wireless Multimedia Sensor Network (WMSN), which composed of autonomous hardware for capturing and transmission of quality audio-visual content. The implementation of DVC in WMSN can better solve the problem of energy constraint of the sensor nodes due to the benefit of lower computational encoder in DVC. In this paper, a practical DVC scheme, pixel-domain Wyner-Ziv(PDWZ) video
coding, with slice structure and adaptive rate selection(ARS) is proposed to solve the certain problems when applying DVC into WMSN. Firstly, the proposed slice structure in PDWZ has extended the feasibility of PDWZ to work with any interleaver size used in Slepian-wolf turbo codec for heterogeneous applications. Meanwhile,
based on the slice structure, an adaptive code rate selection has been proposed aiming at reduce the system delay occurred in feedback request. The simulation results clearly showed the enhancement in R-D performance and perceptual quality. It also can be observed that system delay caused by frequent feedback is greatly reduced, which gives a promising support for WMSN with low latency and facilitates the QoS management
High frequency band communication application in Malaysia
High frequency (HF) radio frequencies are between 3 and 30 MHz.[1] Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters. Shortwave (2.310 - 25.820 MHz)[1] overlaps and is slightly lower than HF. Since the ionosphere often reflects HF radio waves quite well (a phenomenon known as skywave), this range is extensively used for medium and long range terrestrial radio communication. However, suitability of this portion of the spectrum for such communication varies greatly with a complex combination of factors[1]:
âą Sunlight/darkness at site of transmission and reception
âą Transmitter/receiver proximity to terminator
âą Season
âą Sunspot cycle
âą Solar activity
âą Polar aurora
âą Maximum usable frequency
âą Lowest usable high frequency
âą Frequency of operation within the HF rang
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