Measurements Based Interference Analysis at Millimeter Wave Frequencies in an Indoor Scenario

This paper investigates the interference characteristics at 73 GHz carrier frequency based on the realistic measurements in a large entrance hall scenario. In this scenario, 3 millimeter wave (mmWave) access points (APs) are deployed at different floors of the building which are capable of transmitting directional Ultra-Wide Band (UWB) signals to different user equipments (UEs). The interference between the AP's is analyzed from different aspects, with the following interesting results summarized: a) The analysis results confirm the hypothesis that beamforming at both AP/UE along with strongest beam selection greatly reduces the interference. The best case is achieved when both AP and UE use high gain antennas resulting in an average signal to interference power ratio (SIR) of above 45 dB and a signal to interference plus noise power ratio (SINR) of above 30 dB. b) Due to beamforming at the UE, the average interference to noise ratio (INR) always remains lower than 0 dB. c) For systems with considerable beamforming gain, the antenna polarization setup plays an important role regarding both SNR and SIR. Our results have demonstrated an above 4.5 dB difference in SINR of different antenna polarization setups.