A Framework for Crosslayer Optimization in OFDM based Overlay Systems

Kurzfassung

One approach for increasing spectral efficiency is the coexistence of OFDM based overlay systems with an already existing licensed system in the same frequency band. An important issue in overlay systems is to use the changing available bandwidth as efficiently as possible. As the dynamic spectrum allocation influences not only the physical (PHY) layer but also the medium access control (MAC) layer, we present a general framework for crosslayer optimization designed for the special requirements in overlay systems. In the presented crosslayer design not only information about the currently available spectrum is considered, but also further parameters, providing a basis for a joint optimization. As an example, the optimization of throughput is investigated, based on the combined knowledge of the allocation vector and the signal-to-noise ratio.