3,106 research outputs found
Fuzzy Logic Control of Adaptive ARQ for Video Distribution over a Bluetooth Wireless Link
Bluetooth's default automatic repeat request (ARQ) scheme is not suited to video distribution resulting in missed display and decoded deadlines. Adaptive ARQ with active discard of expired packets from the send buffer is an alternative approach. However, even with the addition of cross-layer adaptation to picture-type packet importance, ARQ is not ideal in conditions of a deteriorating RF channel. The paper presents fuzzy logic control of ARQ, based on send buffer fullness and the head-of-line packet's deadline. The advantage of the fuzzy logic approach, which also scales its output according to picture type importance, is that the impact of delay can be directly introduced to the model, causing retransmissions to be reduced compared to all other schemes. The scheme considers both the delay constraints of the video stream and at the same time avoids send buffer overflow. Tests explore a variety of Bluetooth send buffer sizes and channel conditions. For adverse channel conditions and buffer size, the tests show an improvement of at least 4 dB in video quality compared to nonfuzzy schemes. The scheme can be applied to any codec with I-, P-, and (possibly) B-slices by inspection of packet headers without the need for encoder intervention.</jats:p
Power-Constrained Fuzzy Logic Control of Video Streaming over a Wireless Interconnect
Wireless communication of video, with Bluetooth as an example, represents a compromise between channel conditions, display and decode deadlines, and energy constraints. This paper proposes fuzzy logic control (FLC) of automatic repeat request (ARQ) as a way of reconciling these factors, with a 40% saving in power in the worst channel conditions from economizing on transmissions when channel errors occur. Whatever the channel conditions are, FLC is shown to outperform the default Bluetooth scheme and an alternative Bluetooth-adaptive ARQ scheme in terms of reduced packet loss and delay, as well as improved video quality
Robust streaming in delay tolerant networks
Delay Tolerant Networks (DTN) do not provide any end to end connectivity guarantee. Thus, transporting data over such networks is a tough challenge as most of Internet applications assume a form of persistent end to end connection. While research in DTN has mainly addressed the problem of routing in various mobility contexts with the aim to improve bundle delay delivery and data delivery ratio, little attention has been paid to applications. This paper investigates the support of streaming-like applications over DTN. We identify how DTN characteristics impact on the overall performances of these applications and present Tetrys, a transport layer mechanism, which enables robust streaming over DTN. Tetrys is based on an
on the fly coding mechanism able to ensure full reliability without retransmission and fast in-order bundle delivery in comparison to classical erasure coding schemes. We evaluate our Tetrys prototype on real DTN connectivity traces captured from the Rollerblading tour in Paris. Simulations show that on average, Tetrys clearly outperforms all other reliability schemes in terms of bundles delivery service
Stay Tuned: Whether Cloud-Based Service Providers Can Have Their Copyrighted Cake and Eat It Too
Copyright owners have the exclusive right to perform their works publicly and the ability to license their work to others who want to share that right. Subsections 106(4) and (5) of the Copyright Act govern this exclusive public performance right, but neither subsection elaborates on what constitutes a performance made “to the public” versus one that remains private. This lack of clarity has made it difficult for courts to apply the Copyright Act consistently, especially in the face of changing technology.
Companies like Aereo, Inc. and AereoKiller, Inc. developed novel ways to transmit content over the internet to be viewed instantly by their subscribers and declined to procure the licenses that would have been required if these transmissions were being made “to the public.” However, while these companies claimed that their activities were outside of the purview of § 106(4) and (5), their rivals, copyright owners, and the U.S. Supreme Court disagreed. Likening Aereo to a cable company for purposes of § 106(4) and (5), the Supreme Court determined that the company would need to pay for the material it streamed. Perhaps more problematic for Aereo (and other similar companies) is the fact that the Court declined to categorize Aereo as an actual cable company, such that it would qualify to pay compulsory licensing fees—the more affordable option given to cable companies under § 111—to copyright holders.
This Comment shows that, while the Court correctly ruled that companies like Aereo and AereoKiller should pay for the content transmitted, its failure to address whether Aereo is a cable company could frustrate innovation to the detriment of the public. It suggests, therefore, that these companies should be required to pay for the content that they transmit in the same way that cable companies do until Congress develops another system
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