Adaptive control of wireless multimedia links

The quality of wireless links suffers from temporally and spatially varying channel degradations such as noise, interference, and multipath fading. A proper addressing of these impairments is crucial to sustaining quality of service (QoS) in wireless integrated service packet networks such as wireless ATM. Newer radios that allow parameters such as processing gain, symbol rate, and transmit power to be varied on a per packet basis offer interesting opportunities. This paper explores a highly adaptive approach to wireless link control where the various physical and link layer parameters are continually adapted in response to channel and traffic variations. Furthermore, we also explore adaptivity at the upper layer of the protocol stack, since applications typically can not cope with residual distortions in the packet flow. It is illustrated that lower and upper layer adaptation strategies are tightly intertwined, such that they should be managed jointly. Node and basestation architectures to efficiently support such adaptivity are also described