Precoding Design For The Mimo-Roc Downlink

MIMO Radio-over-Copper (MIMO-RoC) is a transport system for indoor coverage that leverages the pre-existing building's copper cabling infrastructure. In MIMO-RoC, the overall channel from the Base Band Units (BBU) to the end-user is the cascade of a MIMO-radio over a MIMO-cable channel and the analog fronthaul together with a wireless channel enables the transport to the mobile users. The entire system poses two main challenges: i) design low-complexity and flexible allocation strategies between wired and wireless resources; ii) design interference cancellation techniques tailored to the mutually coupled wired-wireless interference. While the former has been extensively investigated, the optimal design of precoding algorithms for the MIMO-RoC downlink is still an open issue and is covered here. In particular, in this paper, the Linear Successive Allocation (LISA) algorithm has been revised and adapted to the MIMO amplify-and-forward (AF) structure of MIMO-RoC. Numerical results validate the proposed method considering a realistic radio environment with 100m copper cable remotization.