Supporting adaptive-QOS over multiple time scales in wireless networks

For wireless channels, interference mitigation techniques are typically applied at the packet transmission level. In this paper, we present an adaptive-QOS framework that also responds to impairments over multiple time scales that are present at the ow/session level. Our framework is based on three di erent mechanisms that operate over distinct adaptation time scales. At the packet transmission time scale, a channel predictor determines whether to transmit a packet or not depending on the state of the wireless channel. At the packet scheduling time scale, a compensator credits and compensates ows that experience bad link quality. Over even longer time scales an adaptator regulates ows taking into account the ability of wireless applications to adapt to changes in available bandwidth and channel conditions. In this paper, we argue that to e ectively support QOS across wireless links there needs to be interworking or integration between the predictor, compensator and adaptator. We achieve this by deploying an arbitrator that coordinates the operation of each mechanism in response to environmental factors, scheduling state and ow semantics.