Radio channel measurements in live LTE networks for MIMO Over-the-Air emulation

This paper discusses a radio channel measurement scheme to bring site specific propagation characteristics of a live LTE network to a virtual drive testing in a MIMO Over-the-Air (OTA) emulation environment. A directional radio channel measurement performed in a live LTE network in nine different locations is reported and the modelling procedure for MIMO OTA is described. The channel measurement system is composed of a scanner for LTE network, a directive dual polarized antenna, and a channel analysis & modelling software. Measured radio channel parameters are power angular distribution, power delay profile, received polarization power ratio, Ricean K-factor, antenna correlation, and received signal level. The measurement results indicate, for instance, that the angular power distribution is not uniform, but has a range of variation of up to 22 dB, and that the received polarization power ratio is not 0 dB, but vary in between 13 and -8 dB. Line-of-sight component was present in many locations, the average Ricean K-factor was 3.6 dB.