Experimental Investigation of 5G Base Station functionalities in Reverberation Chamber at Millimeter-Wave

TL;DR

The paper addresses evaluating a commercial mmWave 5G base station in a controlled propagation environment using a reverberation chamber to emulate realistic conditions. It employs OTA measurements with a Nokia $5G$ BS, a UE, and a live core network across $27$–$29$ GHz, while characterizing the channel with metrics such as the Power Delay Profile (PDP) and the coherence bandwidth $B_c$, as well as the $Q$-factor and delay spread $\tau_{RMS}$. The main findings show that a $2\times 2$ MIMO mmWave BS with analog beamforming across $32$ beams can sustain high RSRP, SINR, and throughput up to $550$ Mbps DL and $140$ Mbps UL, adapting beams when the environment changes or blockage occurs; severe reductions in SSB power degrade performance (e.g., to about $259$ Mbps). The study demonstrates the viability of RC-based OTA testing for mmWave 5G and provides operator-relevant insights into the benefits and costs of such deployments in real networks.

Abstract

The performance and functionalities of a commercial fifth generation base station are evaluated inside the reverberation chamber at the mmWave frequency range. The base station capability to operates in different propagation environment conditions reproduced by the reverberation chamber is investigated. Throughput, modulation code scheme and beamforming are analyzed for different real life scenarios both in uplink and downlink. Experimental results inform network operators in their evaluation of the base station operation: i) in many scenarios within a laboratory; ii) in the assessment of whether expected benefit justifies the additional costs in an operating actual network.

Figures (13)

• Figure 1: Schematic description of the set-up. During measurements we considered two antenna orientations labeled as "Pos1" and "Pos2" respectively.
• Figure 2: The top picture shows the GPS antenna used to synchronize the 5G pilot signal. The bottom picture reports the Askey UE used to collect data.
• Figure 3: Quality factor for the different chamber loading condition, EC, ML and UHL. Dotted lines denotes raw data whereas continuous lines are the raw data are after by applying a sliding average in a window of 400 frequency points.
• Figure 4: Coherence bandwidth.
• Figure 5: Inner view of the RC. On the top the ML condition whereas on the bottom the UHL condition. Moreover, for the antenna orientation the top picture denotes "Pos1" whereas the bottom picture refers to "Pos2".