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Transmission Schemes (transmission + scheme)

Distribution by Scientific Domains
Engineering85%

Selected Abstracts

Proxy-assisted P2P and multicast transmission schemes for layered-video streaming over wireless networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9-10 2010
Yung-Cheng Kao
Abstract This work describes the process of efficiently streaming a set of layered-videos from a remote server via proxy of the base station to multiple heterogeneous and asynchronous clients in wireless networks, such as the WiMAX network, which are devices that request different layers of the video according to their profiles. The process focuses on that the transmission cost savings for caching X layers of a video are not only from requests on X layers, but also from requests on layers that are lower than X layers. A set of proxy-assisted transmission schemes are proposed for layered-video streaming by integrating the proxy caching with reactive transmission schemes, peer-to-peer mesh networks and base station multicast capability. The optimal proxy prefix cache allocation is calculated for each transmission scheme to identify the cache layer and cache length of each video to minimize the aggregate transmission cost. Experimental results demonstrate that an adaptive proxy-assisted transmission scheme can lead to significant transmission cost savings. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Harmonic broadcasting is bandwidth-optimal assuming constant bit rate

NETWORKS: AN INTERNATIONAL JOURNAL, Issue 3 2006
Lars Engebretsen
Abstract Harmonic broadcasting was introduced by Juhn and Tseng in 1997 as a way to reduce the bandwidth requirements required for video-on-demand broadcasting. In this article, we note that harmonic broadcasting is actually a special case of the priority encoded transmission scheme introduced by Albanese et al. in 1996, and prove,using an information theoretic argument,that it is impossible to achieve the design goals of harmonic broadcasting using a shorter encoding. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 47(3), 172,177 2006 [source]

Multi-user detection in OFDM systems using CDMA and multiple antennas

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2003
Christoph Degen
This paper deals with linear multi-user detection in orthogonal frequency division multiplexing (OFDM) systems. The separation of concurrently transmitted signals is based on space division and code division multiple access (SD/CDMA). The examined OFDM schemes are compared against frequency domain equalization for single-carrier transmission schemes (SC/FDE). Both show strong similarities. Therefore in this paper, we focus on a unified treatment of multi-user detection systems based on OFDM or SC/FDE. The trade-off between exploitation of diversity and user separation is analyzed for different spreading techniques and a varying number of receive antennas. The performance is evaluated in terms of both uncoded and coded bit error ratio (BER). Furthermore, a novel time domain spreading technique for OFDM systems is proposed for which the peak-to-average transmitter power ratio (PAPR) is independent of the applied spreading code. Copyright © 2004 AEI [source]

Proxy-assisted P2P and multicast transmission schemes for layered-video streaming over wireless networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9-10 2010
Yung-Cheng Kao
Abstract This work describes the process of efficiently streaming a set of layered-videos from a remote server via proxy of the base station to multiple heterogeneous and asynchronous clients in wireless networks, such as the WiMAX network, which are devices that request different layers of the video according to their profiles. The process focuses on that the transmission cost savings for caching X layers of a video are not only from requests on X layers, but also from requests on layers that are lower than X layers. A set of proxy-assisted transmission schemes are proposed for layered-video streaming by integrating the proxy caching with reactive transmission schemes, peer-to-peer mesh networks and base station multicast capability. The optimal proxy prefix cache allocation is calculated for each transmission scheme to identify the cache layer and cache length of each video to minimize the aggregate transmission cost. Experimental results demonstrate that an adaptive proxy-assisted transmission scheme can lead to significant transmission cost savings. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Transmission on indoor power lines: from a stochastic channel model to the optimization and performance evaluation of multicarrier systems

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 5 2003
Virginie Degardin
Abstract This paper deals with optimization and performance evaluation of multicarrier transmissions on indoor power lines, taking the actual channel characteristics into account. From intensive measurements of noise on lines, the most significant parameters of impulsive noise were defined and classified, and then a statistical study was carried out. The other types of noise, i.e. narrow band and coloured noise have also been characterized. In like manner, the transfer functions between two points of a power line network have been measured. From all these data, a stochastic channel model representative of the environment is built and implemented in a software tool simulating the link. Various transmission schemes have been considered to mitigate the effects on one hand of the stationary noise, the channel frequency selectivity and of the change of its state, and on the other, on the impulsive noise. These techniques are optimized for the indoor power line environment and their performances, expressed in terms of bit error rate, are compared. Copyright © 2003 John Wiley & Sons, Ltd. [source]