Modeling the Distributed MU-MIMO OAI 5G testbed and group-based OTA calibration performance evaluation

In this paper we describe the simulation modeling of the OpenAirInterface (OAI) C-RAN testbed deployed at Eurecom and present the performance evaluation of a fast calibration (FC) scheme based on antenna grouping. We generate an indoor LOS radio wave propagation model using ray tracing technique and perform distributed channel reciprocity calibration which is required to exploit uplink (UL) channel estimates to infer the precoder performed on the downlink (DL) channel. We consider a channel based on the geometry of the area where the RRUs are distributed and compare the different choices to form the RRU groups. We validate that the simulation results match the experimental results from our previous work.