A method for estimating local 5G time division duplex patterns using spectrum sensing

Local 5G, which enables autonomous deployment of cellular communication services independent of mobile operators, has attracted much attention. When multiple Local 5G base stations deploy their services at the same time, there is a significant degradation of communication performance due to interference in the same frequency between systems. Therefore, the time for base stations and terminals to access the same frequency interference is different. Therefore, it is effective to identify whether the interference source at each time is a base station or a terminal in order to countermeasure same-frequency interference. However, information on the TDD schedule, which is the switching pattern between uplink and downlink of other Local 5G TDDs in an autonomous system, may not be available. Therefore, in this study, we established a method to estimate the TDD schedule by power detection. By controlling the tilt angle of the antenna deployed at the base station, it is possible to improve the accuracy of discriminating between terminal emissions during the uplink and base station emissions during the downlink. The TDD frame discrimination accuracy of the proposed method was clarified through actual experiments in the millimeter wave band.