A dynamic scheduling based multiple access control for wireless ATM networks

This paper proposes a dynamic scheduling scheme to provide quality of service (QoS) guarantees in multiple access control (MAC) for wireless ATM networks. Token models of sources are constructed in the base station for more flexible slot allocation. In order to deal with the dynamic nature and stringent QoS requirement of rt-VBR such as compressed video source, an emergency token buffer is constructed to raise the priority of the source having deadline in the current MAC frame. After receiving the emergency message, the scheduler in the base station computes the slots required by the source and puts tokens into the emergency token buffer. The emergency token has a higher nonpreemptive priority over those of nrt-VBR and ABR. At the same time, voice sources can be served without reservation when reactived. The scheduling scheme based on polling of token buffers is effective and easy to implement. Simulations are done to evaluate the performance of its efficiency. We found that the scheduling scheme proposed can significantly improve rtVBR loss and delay performance while statistical multiplexing gain is achieved.