Link residual-time estimation for VANET cross-layer design

Traditional network design may underestimate the dependencies between different layers of the protocol stack and fail to exploit the direct coupling of physical-layer operations to the network topology. In the case of a highly dynamic network, as observed in vehicular communications, the network architecture needs to be able to optimally adapt to the changes brought on by nodes´ mobility. In this paper we propose a cross-layer approach, where the received power metric, logged at the physical layer, can be used to produce estimates of the links´ residual lifetime. Such information is crucial for the decision processes of higher layers, such as hand-off, scheduling and routing. The method comprises of utilizing a time series based on physical-layer measurements to estimate the current state of the link and the remaining time during which the link can be used for efficient communication. Shadowing, small scale fading and limited opportunities to sample the channel make the problem challenging. The proposed algorithms are tested against simulations which depict the mobile wireless channel realistically.