Multiplex communications – Channel assignment techniques – Only active channels transmitted
Patent
1996-10-11
1998-11-17
Ton, Dang
Multiplex communications
Channel assignment techniques
Only active channels transmitted
348384, H04J 317
Patent
active
058386866
DESCRIPTION:
BRIEF SUMMARY
The present invention is related to a system for dynamically allocating a scarce resource among several competing users in response to indications of need from the users.
BACKGROUND OF THE INVENTION
It is often necessary for a scarce resource to be shared among several users. For example, a plurality of video signals from respective sources, which may be television network feeds, television stations, or other video sources, may be combined and transmitted over a satellite link for broadcast to respective television receivers in consumers' homes. An exemplary satellite link includes a digital transmission path capable of transmitting 24 megabits per second (Mbps). In order to maximize efficiency and utilization of such a link, it is necessary for several video signals to share the link. For example, it may be desired to share the above satellite transmission link among at least six video signal channels. In this case, the scarce resource is the bandwidth, or bit rate, in the satellite transmission link. This resource is shared in the transmission system by allocating some portion of the bandwidth or bit rate of the transmission link to each of the video signals.
One known method for performing the multiplexing function uses constant bit rate (CBR) encoders for each channel. In such a system, the video signal from each channel is supplied to a CBR encoder. A CBR encoder produces a digitally encoded bit stream, representing the video signal supplied to it, at a predetermined constant bit rate. To produce a constant bit rate signal, a CBR encoder continually modifies the number of quantizing levels into which the video signal is encoded. Using fewer quantizing levels requires fewer bits to represent those levels, and the overall number of bits required to represent the video signal is reduced. Conversely, using more quantizing levels requires more bits to represent those levels, and the overall number of bits required to represent the image is increased.
However, varying the quantization levels in an encoded signal representing an image effects a corresponding change in the quality of the image reproduced from the encoded signal. Using fewer quantization levels results in a lower quality reproduced image than using more quantization levels. Thus, in a CBR encoder, video signals representing spatially and/or temporally more complex images are encoded in such a manner that the quality of the reproduced image is lower than that of less complex images.
Because CBR encoders produce a constant bit rate, controlling the multiplexing of video signals from a plurality of such encoders is simplified. Each encoder is a priori allocated a bit rate representing its quota of the total available bit rate of the transmission link. One known allocation method allocates equal portions of the total bit rate of the transmission link to each encoder. However, video signals representing different program types inherently have differing complexities. For example, a video channel transmitting a basketball game has a much higher complexity than one transmitting a panel discussion. Thus, the quality of the image reproduced from the encoded video signal representing the basketball game will be lower (probably substantially lower) than that of the panel discussion.
Another known allocation method, which attempts to solve this problem, a priori allocates different bit rates to each CBR encoder based on the expected image complexity of the signal to be encoded. Thus, the channel transmitting a basketball game would be allocated a larger proportion of the total bit rate of the transmission link than the channel transmitting the panel discussion. Such an allocation method can result in the quality of the images reproduced from the encoded signals representing both the basketball game and the panel discussion being more nearly equal.
Yet another known allocation method allocates the proportion of the total bit rate of the transmission link to channels based on payment by the provider of the signal. The more the provider pays for the transm
REFERENCES:
patent: 4455649 (1984-06-01), Estehan et al.
patent: 4713776 (1987-12-01), Araseki
patent: 5115309 (1992-05-01), Hang
patent: 5134476 (1992-07-01), Aravind et al.
patent: 5309232 (1994-05-01), Hartung et al.
Haskell, "Buffer and Channel Sharing by Several Interframe Picturephone Coders", The Bell System Technical Journal, vol. 51, Jan. 1972, pp. 261-289.
Kishino et al., "Variable Bit-Rate Coding of Video Signals for ATM Networks", IEEE Journal on Selected Areas in Communications, vol. 7, No. 5, Jun. 1989, pp. 801-806.
Zdepski et al., "Statistically Based Buffer Control Policies for Constant Rate Transmission of Compressed Digital Video", IEEE Transactions on Communications, vol. 39, No. 6, Jun. 1991, pp. 947-957.
Herrmann Eric P.
Kurdyla Ronald H.
Thomson Consumer Electronics Inc.
Ton Dang
Tripoli Joseph S.
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