Mac for WATM air interface: impact of error control schemes on protocol design

The extension of the ATM (asynchronous transfer mode) protocol stack to the wireless segment requires the introduction of a MAC (medium access control) layer able to provide reliable connection services to the network layer. Two basic functions of the MAC layer are resource allocation and error control. In this paper we analyze these issues and consider a MAC scheme for TDMA systems based on ARQ (automatic repeat request) and a multi-level priority scheduling. The impact of radio channel characteristics and QoS requirements on the protocol design has been studied and a comparison of the ARQ-based approach and the classical approach based on FEC (forward error correction) and interleaving has been performed.