A Fast Adaptive Control Algorithm for Slotted ALOHA

—The control algorithm which is in order to achieve the aim of keeping throughput stability is needed in the Slotted ALOHA(S-ALOHA) protocol. The core of the control algorithm is to derive the accurate number of nodes. The classic control algorithm suffers performance loss when the system nodes change. In this paper, we addressed a Fast Adaptive (FA) algorithm to promote the performance of ALOHA. The channels are grouped into two states, idle channel and non-idle channel, by the mode of status run. When 7 continuous idle channel slots are detected, the number of nodes becomes 1/2 the number of estimated nodes at fiducially interval 0.95 and updates the probability of transmitting data on twice the pace. Similarly, channel states are also divided into collision and noncollision. If 7 continuous collision slots are detected, the estimated number of nodes will be doubled and the probability of transmitting data will be updated as 1/2 times. In other cases, the p-persistent control algorithm (pPCA) or Pseudo-Bayesian Control Algorithm (PBCA) are adopted. Simulation results show that the performances of fast adaptive p-persistent control algorithm (FA-pPCA) and fast adaptive pseudo-Bayesian control algorithm (FA-PBCA) outperform those of pseudoBayesian control algorithm and p-persistent control algorithm.