Improving the Degrees of Freedom in MIMO Interference Network via PHY Caching

Interference is a key issue that limits the Degrees of Freedom (DoF) in conventional wireless networks. In this paper, we propose a novel physical layer (PHY) caching scheme to achieve DoF gains in interference networks. Specifically, by properly caching a portion of the content files at each transmitters, the PHY topology can be opportunistically transformed from the unfavorable interference channel topology into a more favorable MIMO broadcast channel topology and enjoy a large DoF gain. We first propose a novel caching scheme to significantly improve the MIMO cooperation opportunity induced by PHY caching. Then we quantify the DoF gain w.r.t. some important system parameters. Both analysis and simulation show that the proposed scheme has significant gains over various baselines.