Design and performance of underlay-overlay cellular networks

We study the design and performance of underlay-overlay (U-O) wireless networks, which promise capacity gains over conventional fixed-reuse cellular networks. To address the two principal problems in U-O networks, namely, (a). Where are the underlay boundaries to be placed? (b). How are the channels to be allocated? we propose an optimization procedure and a traffic model respectively. Our objective is to match spectrum allocated to the underlay to absorption (proportion of underlay traffic), subject to statistical interference constraints. Numerical results demonstrate the effectiveness of our design procedure and suggest substantial capacity gains from U-O networks