Energy-efficient interference-aware precoding for the downlink of multi-cell multi-user MIMO systems

Energy efficiency (EE) is fast becoming a key performance indicator for designing future wireless communication systems. Equally, precoding/power allocation has proved to be very effective for improving the spectral efficiency (SE) of multi-user (MU) multi-input multi-output (MIMO) communication systems. In a multi-cell environment, other-cell interference (OCI) degrades both the SE and EE performances of the system. We design here an energy efficient OCI-aware precoding/power allocation algorithm for the downlink of MU-MIMO systems by relying on regularized channel inversion and considering a realistic multi-antenna power consumption model. The performance of our proposed scheme is assessed both in presence and absence of OCI and results demonstrate the effectiveness of our approach for mitigating OCI. In addition, results show that our approach improves the EE of the system by saving transmit power in comparison with a traditional SE-based precoding/power allocation approach.