A Modular Architecture for QoS Provisioning over Wireless Links

We consider the problem of providing QoS guarantees, and at the same time boosting the throughput or saving energy over a wireless link. A common solution is using a single, integrated scheduler that deals both with the QoS guarantees and the wireless link issues. Unfortunately, such an approach does not allow any of the existing high-quality schedulers for wired links to be used without modification. And it is little flexible, as a scheduler compliant with a given wireless technology may need to be modified to fit a different technology or a different solution for saving energy. To address these issues, in this paper we propose a modular architecture that basically extends the network stack by adding a special middle layer on top of the MAC. On the bottom side, this middle layer deals with the idiosyncrasies of the underlying wireless link, and possibly uses channel state information to boost performance and save energy. On the top side, the middle layer exports the abstraction of a link to which the higher layers must only pass the packets to transmit. On top of this middle layer, existing packet schedulers for wired links can be used without modification. It is then possible also to use the same packet scheduler on heterogeneous wireless technologies, by changing only the the middle layer.