Link quality control for wireless ATM networks

The data link control (DLC) scheme is essentially needed in the protocol stack of wireless ATM systems in order to overcome the incompatibility between the ATM design assumptions and the characteristics of the physical radio channel. In this paper, the DLC scheme developed for the ACTS project Magic WAND (wireless ATM network demonstrator) is evaluated by taking into account a finite state radio channel model which allows to describe the radio transmission quality by a stochastic process. Due to the fact that the transmission quality for two subsequent time slots becomes correlated, this channel model is especially suited to evaluate the performance of error control and retransmission schemes. In particular, we compared the transmission scheme without error control to a scheme with a limited ARQ (automatic repeat request) mechanism by evaluating the cell loss ratio. When considering network services with different maximum delay requirements, these results allow to determine for which services ARQ schemes are beneficial