1 Resource Allocation in Hybrid Macro/Femto Networks1

Abstract—Femtocell has been considered by the wireless industry as a promising solution not only to improve indoor coverage, but also to unload traffic from overburdened macrocell networks. In hybrid macro/femto networks, macrocells may have to share the same spectrum with femtocells, due to spectrum availability and network infrastructure considerations, in spite of potentially excessive interference caused by densely deployed femtocells. In this paper, we propose a decentralized resource allocation scheme for the orthogonal frequency division multiple access (OFDMA) downlink of a shared-spectrum macro/femto network, where each femtocell randomly selects a subset of available OFDMA resources for transmission, in order to achieve decentralized inter-cell interference avoidance. The performance of the decentralized resource allocation scheme is evaluated by simulations based on per-cell or network-wide performance metrics. Simulation results provide insights on how the resource allocation in a shared-spectrum hybrid macro/femto network should take into account the spatial density of femtocells and indoor/outdoor radio propagation channel conditions. Keywords—Femtocell, macrocell, OFDMA, resource block (RB), outage probability, areal spectral efficiency (ASE). I