francisco quiles - Academia.edu (original) (raw)
Papers by francisco quiles
IEEE Transactions on Broadcasting, 1998
ATM networks promise to provide the means to support a wide range of applications exhibiting diff... more ATM networks promise to provide the means to support a wide range of applications exhibiting different traffic characteristics and performance requirements. Video communications have been recognized as one of the most demanding applications to be supported by ATM networks. This is mainly due to the need of transferring large amounts of data and the strict timing requirements characterizing digital video applications. In this paper, simulation experiments are conducted to study the performance of the different cell discarding control mechanisms, in terms of quality of service, when used in an ATM network supporting hierarchical encoded VBR MPEG-2 video distribution. Our results show the effectiveness of the control schemes in reducing the cell loss rates as compared to the system configuration without no cell discarding scheme in place.
IEEE Transactions on Broadcasting, 1999
MPEG-2 video communications over ATM networks is one of the most active research areas in the fie... more MPEG-2 video communications over ATM networks is one of the most active research areas in the field of computer communications. In the transmission process of a variable bit rate video signal over an ATM network, cells are inevitably exposed to delays, errors and losses due to the statistical multiplexing used in these networks. These phenomena affect the quality of the video signal and without adequate measures to control the propagation of the impairments the quality of the service may fall below acceptable levels. In this paper, we study the impact of cell losses on the quality of a MPEG-2 video sequence encoded in a variable bit rate mode. We introduce a set of control mechanisms at different levels of the protocol architecture to be used in MPEG-2based video communications systems using ATM networks as their underlying transmission mechanism. Our results (using different video sequences) show the effectiveness to improve the video quality by using a structured set of control mechanisms to overcome for the loss of cells carrying VBR MPEG-2 video streams. We argue that in order to be able to create video systems able to cope with cell losses encountered in computer communications systems, a structured set of error-resilient protocol mechanisms is needed.
We introduce a set of control mechanisms at different levels of the protocol architecture to be u... more We introduce a set of control mechanisms at different levels of the protocol architecture to be used in MPEG-2-based video communications systems using ATM networks as their underlying transmission mechanism. Our results show the effectiveness of using a structured set of control mechanisms to overcome for the loss of cells carrying VBR video streams
In the transmission process of a video signal over ATM networks, cells are inevitably exposed to ... more In the transmission process of a video signal over ATM networks, cells are inevitably exposed to delays, errors and losses due to the statistical multiplexing used in these networks. These phenomena effect the quality of the video signal and without adequate measures to control the propagation of the impairments the quality of the service may fall below acceptable levels. In
The effective deployment of distributed video applications will rely on the services provided by ... more The effective deployment of distributed video applications will rely on the services provided by the underlying transport mechanism. In the context of ATM-based networks, effective traffic control mechanisms remains one of the major challenges towards the design of network services guaranteeing low cell losses probabilities. In the case of compressed video, the loss cells have the effect of affecting blocks of information relying on the lost information. When cell loss occurs, error concealment schemes can play an important role in recovering the viewing quality of impaired video. Error concealment schemes make use of the redundancies still remaining in the frequency, temporal and spatial domains after compression. Under these schemes, the remaining redundancy in the compressed video stream may be used to recover the lost information, making the cell loss effect subjectively imperceptible. We review the state-of-the-art on error concealment schemes for MPEG-2 transmission over ATM networks
IEEE Transactions on Broadcasting, 1998
ATM networks promise to provide the means to support a wide range of applications exhibiting diff... more ATM networks promise to provide the means to support a wide range of applications exhibiting different traffic characteristics and performance requirements. Video communications have been recognized as one of the most demanding applications to be supported by ATM networks. This is mainly due to the need of transferring large amounts of data and the strict timing requirements characterizing digital video applications. In this paper, simulation experiments are conducted to study the performance of the different cell discarding control mechanisms, in terms of quality of service, when used in an ATM network supporting hierarchical encoded VBR MPEG-2 video distribution. Our results show the effectiveness of the control schemes in reducing the cell loss rates as compared to the system configuration without no cell discarding scheme in place.
IEEE Transactions on Broadcasting, 1999
MPEG-2 video communications over ATM networks is one of the most active research areas in the fie... more MPEG-2 video communications over ATM networks is one of the most active research areas in the field of computer communications. In the transmission process of a variable bit rate video signal over an ATM network, cells are inevitably exposed to delays, errors and losses due to the statistical multiplexing used in these networks. These phenomena affect the quality of the video signal and without adequate measures to control the propagation of the impairments the quality of the service may fall below acceptable levels. In this paper, we study the impact of cell losses on the quality of a MPEG-2 video sequence encoded in a variable bit rate mode. We introduce a set of control mechanisms at different levels of the protocol architecture to be used in MPEG-2based video communications systems using ATM networks as their underlying transmission mechanism. Our results (using different video sequences) show the effectiveness to improve the video quality by using a structured set of control mechanisms to overcome for the loss of cells carrying VBR MPEG-2 video streams. We argue that in order to be able to create video systems able to cope with cell losses encountered in computer communications systems, a structured set of error-resilient protocol mechanisms is needed.
We introduce a set of control mechanisms at different levels of the protocol architecture to be u... more We introduce a set of control mechanisms at different levels of the protocol architecture to be used in MPEG-2-based video communications systems using ATM networks as their underlying transmission mechanism. Our results show the effectiveness of using a structured set of control mechanisms to overcome for the loss of cells carrying VBR video streams
In the transmission process of a video signal over ATM networks, cells are inevitably exposed to ... more In the transmission process of a video signal over ATM networks, cells are inevitably exposed to delays, errors and losses due to the statistical multiplexing used in these networks. These phenomena effect the quality of the video signal and without adequate measures to control the propagation of the impairments the quality of the service may fall below acceptable levels. In
The effective deployment of distributed video applications will rely on the services provided by ... more The effective deployment of distributed video applications will rely on the services provided by the underlying transport mechanism. In the context of ATM-based networks, effective traffic control mechanisms remains one of the major challenges towards the design of network services guaranteeing low cell losses probabilities. In the case of compressed video, the loss cells have the effect of affecting blocks of information relying on the lost information. When cell loss occurs, error concealment schemes can play an important role in recovering the viewing quality of impaired video. Error concealment schemes make use of the redundancies still remaining in the frequency, temporal and spatial domains after compression. Under these schemes, the remaining redundancy in the compressed video stream may be used to recover the lost information, making the cell loss effect subjectively imperceptible. We review the state-of-the-art on error concealment schemes for MPEG-2 transmission over ATM networks