Distributed retransmission controls for slotted, nonpersistent, and virtual time CSMA

A class of distributed retransmission controls based on stochastic approximation techniques is developed for the infinite-population, slotted, nonpersistent, and virtual-time CSMA channels. These controls, which permit each terminal to adjust its retransmission probability in a simple, recursive manner as a function of channel feedback, are stable in terms of the geometric ergodicity of an imbedded Markov chain model for each channel. Simulation results demonstrate the effectiveness of the controls in supporting stable channel operation at maximum achievable throughput, recovering from an abrupt arrival of a larger number of new packets, and providing delay versus throughput performance that closely approximates that of an idealized channel in which each terminal has perfect knowledge of the number of blocked (collided) terminals