Interference Management through Interference Alignment in Multi User Heterogeneous Cellular Networks

Enhanced interference coordination mechanisms have been proposed to overcome the inter cell interference problem in co-channel Heterogeneous Cellular Networks (HetNets). However, these mechanisms sacrifice the macro-layer resources and put high requirements on backhaul for coordination. Here we propose a novel approach for the interference management in HetNets which requires neither coordination nor does it sacrifice the resource utilization in macro-layer. It is simply based on the transmit precoding design using Multi User Inter Cell Interference Alignment (MUICIA). The idea is to align the multi user interference subspace with the partial inter cell interference subspace and suppress the subspace at the desired receiver. We show that MUICIA achieves higher mean cell rates than the state of the art transmit precoding schemes in HetNets. Moreover, we compare the performance of MUICIA with time domain interference coordination and show that MUICIA provides higher spectral efficiency as well as fair resource utilization in co-channel HetNets.