VD/VS coupling scheme using feed-forward congestion indication for ABR services in wireless ATM

This paper explores virtual destination (VD) I virtual source (VS)-based av ailable bit rate (ABR) flow control performance, targeting wireless asynchr onous transfer mode (WATM) application that can incur long link-delays beca use of employing radio-medium sharing and/or radio-specific data link contr ol schemes. As this paper reveals, the conventional VD/VS scheme has diffic ulty in sustaining satisfactory ABR performance, when it is applied to long -delay-causing WATM; it suffers from significant increase in the necessary buffer capacity. To ensure the ABR performance in WATM, this paper proposes a new VD/VS coupling scheme using a feed-forward congestion indication. Th e proposed scheme controls the allowed cell rate of a source end system in a feed-forward manner by predicting the queue length at the time the WATM-a ssociated-round-trip ahead. Simulation results show that the proposed schem e exhibits excellent ABR performance with a long delay of the divided loop on the radio-link side. It is also verified that the proposed scheme is rat her robust against uncertainty and/or time-variation regarding the predeter mined radio link delay.