Uplink interference mitigation for “Dead Zone” problem in closed access femtocell networks

One of the most critical issues in two-tier femtocell networks is the inter-cell interference management, in which Femtocell Base Station (FBS) locating in the edge area of the Macrocell Base Station (MBS) coverage suffers from interference produced by adjacent Macrocell User (MU), making this area a “Dead Zone” to the FBS. In this paper, we study the uplink cross-tier interference for “Dead Zone” problem in closed access femtocell networks from the aspect of resource allocation based on orthogonal frequency division multiple access (OFDMA). We propose a resource-reallocation based strategy to mitigate the cross-tier interference, which reassigns the subchannels and power among MUs and the impaired FUs after the latter ones handover from the serving FBS to the MBS. Theoretical analysis and simulation results confirm that higher throughput can be achieved by our proposed strategy.