An Alternative Viewpoint on the (Cross–)Layering in Wireless Networks

The capacity of a communication network depends on the mode in which the network is operated. The operational mode is determined by the network protocols, which are in turn built within a layered architecture. In the recent years there has been an abundance of efforts to optimize the protocols in the wireless networks through a cross–layer design, which is an approach that goes beyond the application of the strict layering. These efforts are mostly motivated by the fact that the wireless networking offers an immense multitude of possibilities for interaction among the nodes, since it possesses dynamically defined links over a shared wireless medium. In that sense, the current OSI–layering paradigm appears over–restrictive with respect to the operation modes of a wireless network. Therefore, in this paper we take an alternative view on the layering in wireless networks. Within the new layering paradigm, a communication task is decomposed into subtasks that are defined to be more general than the subtasks defined within the OSI–layering. The new layering paradigm aims to set a ground for systematic building of wireless network protocols by accounting for the operational modes that are inherent to the wireless network, such as broadcast transmissions, links with variable data rates, possibility to use cooperative diversity etc. As a bottom line, the presented alternative layering sets the stage for building cooperative protocols in the wireless networks.