Multi User Inter Cell Interference Alignment in Heterogeneous Cellular Networks

We address the issue of interference in co-channel heterogeneous cellular networks where low-power pico cells are overlaid on high-power macro cells. Interestingly, unlike homogeneous networks, the co-channel heterogeneous networks exhibit special interference characteristics. This stems due to the transmit power mismatch in macro and pico layers. Interference alignment is one of the techniques that has been proposed to manage the interference in homogeneous macro cellular networks. Hence it is important to analyse the impact of power mismatch on interference alignment in the heterogeneous networks. For this purpose, we assess the performance of multi user inter cell interference alignment based transmit precoding scheme with different user selection methods in a heterogeneous network scenario. The results for pico cells show that the interference alignment based transmit precoding is well supported by the alignment based user selection method. Additionally, we compare the performance of alignment based transmit precoding with the state of the art non-alignment based precodings. We find that interference alignment is more robust to the power mismatch than its non-alignment based counterparts. This suggests that interference alignment can also be exploited as interference management scheme in co-channel heterogeneous networks.