Managing Interference Through Discrete Modulation and Liquid Metal Antennas

We pursue interference mitigation via the integration of two key ideas. First, understanding the behavior of available rates under discrete signaling which has recently been shown to be promising in the interference channel. This part calls for calculation of good bounds on post-interference mutual information under discrete signaling, as a function of the forward and cross channel gains. Second, the capacity of the interference channel is known to be very irregular, so for any target capacity there are “outage” sets that we aim to avoid by using reconfigurable antennas. For the first component, we report an analytical lower bound on the mutual information and establish a constant gap $O(\log\gamma)$ to capacity (excepting an outage set) that is derived using a purely discrete signaling. This result outperforms the gap reported by Dytso et al that was generated via a mixed discrete-continuous input strategy. In the second part of this work, we propose to use a reconfigurable antenna technology involving liquid metal antennas that can steer the channel away from the outage scenarios and therefore facilitate higher values of coded rates for the two-user symmetric Gaussian interference channel. The viability of the proposed technique is studied via simulations.