Proceedings ArticleDOI
Voice over IP: improving the quality over wireless LAN by adopting a booster mechanism: an experimental approach
Christian Hoene,Iacopo Carreras,Adam Wolisz +2 more
- Vol. 4522, pp 157-168
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TLDR
In this paper, the authors describe the design and implementation of a speech property based booster that improves the quality of voice over wireless LANs, which uses characteristics of human speech production and features of modern audio codecs to distinguish packets regarding their importance for perceptual quality.Abstract:
The performance of unreliable voice transmission (Voice over IP) over wireless links is measured not by the throughput but by the perceptual speech quality. The speech quality is impaired by packet losses, which are common on wireless links, and by high transmission delays. In this paper, we describe the design and implementation of a novel Speech Property Based Booster that improves the quality of voice over wireless LANs. This booster is in compliance with existing standards and is transparent to other protocols. It uses characteristics of human speech production and features of modern audio codecs to distinguish packets regarding their importance for perceptual quality. Important packets are protected at the link layer by three mechanisms: selective packet loss recovery, redundant transmission and a hybrid solution. These mechanisms have been evaluated using an experimental set-up with commercial wireless LAN equipment. We made measurements of the objective audio quality and analyzed the effects of packet losses, both due to real wireless channels and late packet arrivals. Our experiments show that the booster increases the quality of voice best with the hybrid solution and that the performance of Voice over IP can be improved further.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.read more
Citations
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Dissertation
Methods for quality enhancement of voice communications over erasure channels
TL;DR: A novel technique combining this method and the Papoulis-Gerchberg algorithm is proposed with the aim of exploring synergies in the reconstruction of voice signals, which contributes to enhance the performance of the signal reconstruction when using the maximum and minimum dimension processes.
Patent
Vorrichtung und verfahren zur streambeschleunigung anhand einer transparenten proxy-architektur
Proceedings ArticleDOI
Access point-coordinated contention resolution for channel access in wireless LANs
TL;DR: This paper proposes a new channel access mechanism, ARC, which promotes collaboration among competing wireless STAs in order to provide better channel utilization, better support for QoS demanding flows, and to resolve the bias against the AP.
Performance of MAC- IEEE802.11n-Over-Fiber Network in Presence of Errors in the Transmitting Channel
TL;DR: An analytical model is presented to evaluate the MAC-protocol performance of the IEEE802.11n-over–fiber network with taking into account probability of error occurring in the transmitting channel, and utilizing the RTS/CTS mechanism shows higher immunity than basic access mechanism when the network is utilized by high number of users.
References
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RTP: A Transport Protocol for Real-Time Applications
TL;DR: RTP provides end-to-end network transport functions suitable for applications transmitting real-time data over multicast or unicast network services and is augmented by a control protocol (RTCP) to allow monitoring of the data delivery in a manner scalable to large multicast networks.
Journal ArticleDOI
A comparison of mechanisms for improving TCP performance over wireless links
TL;DR: The results show that a reliable link-layer protocol that is TCP-aware provides very good performance and it is possible to achieve good performance without splitting the end-to-end connection at the base station.
Proceedings ArticleDOI
Adaptive playout mechanisms for packetized audio applications in wide-area networks
TL;DR: The authors investigate the performance of four different algorithms for adaptively adjusting the playout delay of audio packets in an interactive packet-audio terminal application, and indicate that an adaptive algorithm which explicitly adjusts to the sharp, spike-like increases in packet delay can achieve a lower rate of lost packets.
The institute of electrical and electronics engineers
Hendley Blackmon,Joseph Weil,Dir-ector Emieritufs,Staff Consultant,Field Operations,Elwood K. Gannett +5 more
TL;DR: Find out more about the ANSI/IEEE C2 National Electrical Safety Code and recommended practice for sizing Lead-Acid Batteries for Stationary Applications.
Proceedings ArticleDOI
IEEE 802.11 wireless LAN: capacity analysis and protocol enhancement
TL;DR: An analytical formula for the protocol capacity is derived and a distributed algorithm is proposed which enables each station to tune its backoff algorithm at run-time and indicates that the enhanced protocol is very close to the maximum theoretical efficiency.
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