A 9/18 kBd Wireless Videophone Scheme
A 9/18 kBd Wireless Videophone Scheme
A highly bandwidth efficient, fixed but arbitrarily programmable rate, perceptually weighted Discrete Cosine Transform (DCT) based video communicator for quarter common intermediate format (QCIF) videophone-sequences is presented. Perceptually weighted cost/gain controlled motion compensation and quad-class DCT-based compression is applied without variable rate compression techniques and without adaptive buffering in order to maintain a fixed transmission rate, which can be adjusted to any required value. In this treatise we opted for a source coded rate of 11.36 kbps and the sensitivity matched forward error correction (FEC) coded rate became 20.32 kbps. A partial forced update technique was invoked in order to keep transmitter and receiver aligned amongst hostile channel conditions. When using coherent pilot symbol assisted 16-level quadrature amplitude modulation (16-PSAQAM), an overall signalling rate of 9 kBd was yielded. Over lower quality channels 4QAM had to be invoked, which required twice as many time slots to accommodate the resulting 18 kBd stream. Over the best Gaussian and worst Rayleigh channels signal-to-noise ratio (SNR) values in the range of 7 to 20 dB were needed for these modems in order to maintain near-unimpaired image quality. In a bandwidth of 200 kHz, similarly to the GSM speech channel, 16 and 8 videophone users can be supported, when using the 16QAM and 4QAM systems, respectively.
2.5-1.6
Streit, J.
49bf5c3e-e995-4441-ac68-7feecb6a6f1d
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1
April 1995
Streit, J.
49bf5c3e-e995-4441-ac68-7feecb6a6f1d
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1
Streit, J. and Hanzo, L.
(1995)
A 9/18 kBd Wireless Videophone Scheme.
Proc. of 2nd International Workshop on Mobile Multimedia Communications, Bristol University, United Kingdom.
11 - 14 Apr 1995.
.
Record type:
Conference or Workshop Item
(Paper)
Abstract
A highly bandwidth efficient, fixed but arbitrarily programmable rate, perceptually weighted Discrete Cosine Transform (DCT) based video communicator for quarter common intermediate format (QCIF) videophone-sequences is presented. Perceptually weighted cost/gain controlled motion compensation and quad-class DCT-based compression is applied without variable rate compression techniques and without adaptive buffering in order to maintain a fixed transmission rate, which can be adjusted to any required value. In this treatise we opted for a source coded rate of 11.36 kbps and the sensitivity matched forward error correction (FEC) coded rate became 20.32 kbps. A partial forced update technique was invoked in order to keep transmitter and receiver aligned amongst hostile channel conditions. When using coherent pilot symbol assisted 16-level quadrature amplitude modulation (16-PSAQAM), an overall signalling rate of 9 kBd was yielded. Over lower quality channels 4QAM had to be invoked, which required twice as many time slots to accommodate the resulting 18 kBd stream. Over the best Gaussian and worst Rayleigh channels signal-to-noise ratio (SNR) values in the range of 7 to 20 dB were needed for these modems in order to maintain near-unimpaired image quality. In a bandwidth of 200 kHz, similarly to the GSM speech channel, 16 and 8 videophone users can be supported, when using the 16QAM and 4QAM systems, respectively.
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Published date: April 1995
Additional Information:
MoMuc-2 Event Dates: 11-14 April 1995 Address: Bristol, UK
Venue - Dates:
Proc. of 2nd International Workshop on Mobile Multimedia Communications, Bristol University, United Kingdom, 1995-04-11 - 1995-04-14
Organisations:
Southampton Wireless Group
Identifiers
Local EPrints ID: 251356
URI: http://eprints.soton.ac.uk/id/eprint/251356
PURE UUID: 6555d4e6-52cf-4e19-964d-493dbfcee1b3
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Date deposited: 28 Oct 1999
Last modified: 18 Mar 2024 02:32
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Contributors
Author:
J. Streit
Author:
L. Hanzo
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