Proposal for a Cross-Layer Coordination Framework for Next Generation Wireless Systems
http://www.citeulike.org/user/scottr/article/782458
In this short paper, Defrawy et al propose a simple framework for cross-layer protocol design. Their argument is that by standardising the interfaces that layers of the protocol stack use to communicate with each other we can maintain the modularity of the stacks, while still benefitting from the use of cross-layer techniques.
A Cross Layer Server sits outside of the protocol stack. A Cross Layer Client is added to each of the layers in the stack and communicates with the server. Each client contains an adaptation module, which implements the logic to adapt the behaviour of the layer dependent on signals from the server. The layer state is abstracted and stored globally by the server, so that other layers can access it. Layer events are passed to the server, which notifies other interested layers, who then run their adaptation algorithm. By implementing the adaptation algorithm within the client, designers can leave the existing protocol layers almost untouched, while easily changing the way in which they react to the cross-layer information.
The protocol designer needs to specify a) the adaptation algorithm for certain layers, b) the events and their parameters and c) a priority policy for the server to use in the case of multiple events. The authors show how a cross-layer aware video transmission protocol can be implemented using their framework.
The paper also references several other papers which summarise the state of cross-layer techniques, so I will be hunting those down once I can get access to the full-text of the IEEE Communications Magazine.
Add comment August 2nd, 2006