Analog MIMO RoC Passive Relay for Indoor Deployments of Wireless Networks

Most of the indoor coverage issues arise from network deployments that are usually planned for outdoor scenarios. Moreover, the ever-growing number of devices with different Radio Access Technologies (RATs), expected for new 5G scenarios and to maintain compatibility with older cellular standards (mostly 3G/4G), worsen this situation thus calling for novel bandwidth-efficient, low-latency and cost-effective solutions for indoor coverage. To solve this problem, Centralized Radio Access Network (C-RAN) architectures have been proposed to provide dense and controlled coverage inside buildings. However, all-digital C-RAN solutions are complex and expensive when indoor layout constraints and device costs are considered. We discuss here an analog C-RAN architecture, referred to as Analog MIMO Radio-over-Copper (A-MIMO-RoC), that aims at distributing RF signals indoors over distances in the order of 50 m. The all-analog passive-only design presented here proves the feasibility of analog relaying of MIMO radio signals over LAN cables at frequency bandwidth values up to 400 MHz for multi-RAT applications. After asserting the feasibility of the A-MIMO-RoC platform, we present some experimental results obtained with the proposed architecture. These preliminary results show that the A-MIMO-RoC system is a valid solution towards the design of dedicated 4G/5G indoor wireless systems for the billions of buildings which nowadays still suffer from severe indoor coverage issues.