On the noisy MIMO interference channel with CSI through analog feedback

In this paper we propose a transmission protocol through which base stations (BSs) and user equipments (UEs) acquire the necessary channel state information (CSI) for Interference Alignment (IA) transmit (Tx) and receive (Rx) filters design. We focus our attention on the frequency-flat noisy MIMO interference channel (IFC) without symbol extension and with initial assumption of no CSI neither at the BS nor at the UE. Each device acquires the necessary CSI through channel training and analog feedback. We consider optimizing the sum rate by focusing in particular on the resulting degrees of freedom (DoF). This approach allows us to easily optimize any set of parameters to unveil the trade-off between the cost and the gains associated to CSI acquisition overhead.