  We propose an approach where each user independently seeks to minimize the
amount of time that they occupy the channel. Essentially, we seek to minimize
the number of transmitted symbols required to communicate a packet assuming
variable-length coding with feedback. Users send a pilot sequence to estimate
the channel quality and decide whether to proceed with a transmission or wait
for the next opportunity. Thus a user may choose to leave the channel even
though it has already gained access, in order to increase the network
throughput and also save its own energy resources. This paper optimizes the
number of pilots and the channel identification threshold to minimize the total
number of transmitted symbols (including pilots) required to communicate the
packet. We prove a sufficient condition for the optimal pilot length and the
channel identification threshold. This optimal parameter pair is solved
numerically and the reduction in channel occupancy is shown for various channel
settings.
