Shared UE-side Distributed Antenna System (SUDAS)

SUDAS is an indoor mobile coverage solution delivering very reliable connectivity and high throughput that can be flexibly tailored to end user data rate needs.

A SUDAS infrastructure is based on many low-cost and low-power relay nodes distributed in an indoor environment (Shared UE-side Distributed Antenna Components, SUDACs). Those SUDACs are easy to deploy. They receive signals from different base stations and forward them in an mm-wave band (relaying). The signals can then be received by multiple user equipment (UEs) in a building or vehicle. Uplink communication follows the same path in reverse.

By combing massive MIMO (multiple input multiple output) and mm-wave communication SUDAS acts as a mobile signal booster that enhances in-building mobile coverage. It can play a significant role in the future 5G-Advanced and 6G indoor communications market by providing a generalized solution suitable for all indoor and even certain outdoor environments. In outdoor areas, SUDAS extends the coverage of mobile networks, enabling to fill coverage gaps without the need for installing additional base stations.

SUDAC nodes communicate with the UEs at high frequencies in the mm-wave range (FR2) whereas base stations send spatial streams to the relay nodes using signals in the conventional sub-6 GHz range (FR1). The outdoor base stations are based on massive MIMO technology and equipped with a large number of antennas to provide large spatial multiplexing. However, besides the worse indoor reception conditions, UEs have so far also suffered from a limited number of antennas, meaning they eventually become the main bottleneck in attaining very-high throughputs. SUDAS solves this problem by virtually extending the number of distributed antennas on the UE-side in a cooperative fashion, which is referred to as virtual MIMO.

SUDAS thus combines the virtues of massive MIMO from the base station and virtual MIMO of SUDACs to transform large spatial multiplexing in FR1 bands into frequency multiplexing in FR2 bands. The higher the number of installed SUDACs, the better the ratio in the spatial-to-frequency translation gets. The throughput on the UE side gets enhanced linearly by the number of SUDACs. In this way, the throughput can be flexibly tailored to end user data rate needs.

Early-stage demonstrator presented at the test center