This is a form of bandwidth management, and is essentially the same thing as statistical multiplexing.
Called "statistical multiplexing," a sports program can use bandwidth not used by a static talking-heads show on that transponder.
In statistical multiplexing, a communication channel is divided into an arbitrary number of variable bit-rate digital channels or data streams.
At the higher data link layer of communication, asynchrony is synonym of statistical multiplexing, such as in packet mode.
This is combined with time domain statistical multiplexing; i.e., packet mode communication, which makes it possible for several users to share the same frequency channel.
Through statistical multiplexing, it's entirely possible to have more than a thousand users share 100Mbps worth of capacity.
Station management believes that six digital subchannels can fit into the spectrum, using statistical multiplexing.
Packet and cell networks were designed to perform statistical multiplexing.
Over-provisioning is a form of statistical multiplexing that makes liberal estimates of peak user demand.
Below that is the data link layer, in charge of packet mode statistical multiplexing and frame synchronization.