Layered architecture and modules of CANA supporting dual mode HiperLAN/2

The centralized ad-hoc network architecture (CANA) is an efficient way to support dual mode systems, [Oikonomou, K, et al., Sept. 2003]. A dual mode of operation has been introduced in the traditional 5 GHz HiperLAN/2 to allow data off-loading by using resources of an ad-hoc network created at 60 GHz (the dual mode concept was introduced by the IST BroadWay project, IST-2001-32686). The off-loading is possible using CANA but certain changes in the standard HiperLAN/2 protocol stack are required and certain algorithms need to be incorporated. In this paper, the new enhanced protocol stack of HiperLAN/2 that supports CANA is presented as well as key algorithms that need to be developed and whose performance is crucial for the efficient utilization of the system resources. These algorithms can also be implemented for any other WLAN in order to support a second mode of operation. Simulations shed light into the trade-offs induced by the dual mode of operation and the way the network resources may efficiently be utilized under certain conditions.