In this work some modifications to the evaluation of PRMA protocols are presented. First, a more realistic voice model which takes in account the hangover of the speech detector is used, based on ITU-T P-84 recommendation. Second, the Front End Clipping (FEC) is calculated and taken as a limiting parameter instead of the dropping probability. Unlike this last, the FEC is a standard parameter to...

This paper explores packet loss recovery in client-server Automatic Speech Recognition (ASR) systems. A forward error correction (FEC) system is designed and tested over several channel loss models, at variable amounts of data acquisition delay. In experiments with simulated packet loss, the FEC system provides robust ASR performance which degrades gracefully as packet loss rates increase. Comp...

In the dynamic multicast environment, static multicast retransmission modes may lead to congestion and loss of packets due to propagation errors of the wireless network. This paper logically divides the dynamic multicast network into fixed and mobile parts, and focuses on the dynamic wireless environment, where mobile member may enter in non-covered areas. The group is divided into many subgrou...

Video content can be provided to an end user by transmitting video data as a sequence of internet protocol (IP) packets over the network. When the network contains a wireless link, packet erasures occur because of occasional deep fades. In order to maintain a sufficient video quality at the end user, video packets must be protected against erasures by means of a suitable form of error control. ...

Applying forward error correction (FEC) in offline streaming with large buffering time dramatically improves the quality and performance of communications under challenging network conditions. However real-time streaming puts hard restrictions on the buffer size and therefore does not allow FEC to compensate for long link failures on single path routes. However, multi-path routing, orthogonal t...

Modern wireless communication systems suffer from phase shifting and, more importantly, from interference caused by multipath propagation. Multipath propagation results in an antenna receiving two or more copies of the signal sequence sent from the same source but that has been delivered via different paths. Multipath components are treated as redundant copies of the original data sequence and ...

In interactive voice applications, FEC schemes are necessary for the recovery from packet losses. These schemes need to be simple with a light coding and decoding overhead in order to not impact the interactivity. The objective of this paper is to study a well known simple FEC scheme that has been proposed and implemented [1], [2], in which for every packet , some redundant information is added...

Packet loss and delay in the Internet degrades the quality of Voice over IP (VoIP). Forward error correction (FEC) reduces packet loss at the cost of higher delay and bandwidth. An alternative is a loss-robust voice codec, but also at the expense of higher bit-rates. We compare the perceived quality of both schemes under the same bandwidth requirement. We evaluate two conventional low bit-rate ...

Forward Error Correction (FEC) techniques have been adopted to overcome packet losses and improve the quality of video delivery. The efficiency of the FEC has been significant compromised, however, due to the characteristics of the wireless channel such as burst packet loss, channel fluctuation and lack of QoS support. We propose herein an Adaptive Cross-Layer FEC mechanism (ACFEC) to enhance t...

One of the most important technical problems in reliable multicast protocol is reducing redundant NAKs to avoid NAK implosion. A number of NAK suppression mechanisms have been proposed to deal with this problem. In the MBONE, which is a virtual multicast network and makes multi-point communication across the Internet feasible, the source link, the links directly connected to or very close to th...