Buffer control for variable bit rate video over wireless ATM LAN

The derivation of the constraints on the encoded bit rate of a video signal imposed by a channel, encoder and decoder buffers is important in the context of video transmission over a wireless channel. In this paper, we derive the conditions for buffer control to ensure that the buffers do not overflow or underflow when video is transmitted over a variable bit rate channel. Using these conditions and a commonly proposed network-user contract, the effect of a network policing function (or usage parameter control function) on the allowable variability of the encoded video bit rate is examined. The details of how these effects might be implemented in a system that controls both the encoded and transmitted bit rates is also presented.