A predictive self-tuning fuzzy-logic feedback rate controller

This paper addresses the design and analysis of an end-to-end rate-based feedback flow control algorithm motivated by the available bit rate (ABR) service in wide-area asynchronous transfer mode (ATM) networks. Recognizing that the explicit feedback rate at time t will not affect the ABR buffer until time t+D for some D/spl ges/0, our approach is to first predict the ABR buffer status at time t+D, then base fuzzy-logic rate control decisions on these predicted values, and finally tune the controller parameters using gradient descent methods. Simulations show that this predictive self-tuning fuzzy-logic (PSTF) control scheme is efficient, stable, and outperforms other proposed ABR rate controllers in a variety of network environments. With delays corresponding to a US coast-to-coast connection, the PSTF controller can maintain high link utilization, avoid buffer overflows, and provide fair allocation of resources.