Method and apparatus for spatial filtering using difference between PROPAGATION Delay of electromagnetic signal and ACOUSTIC signal

摘要

The present invention provides a method and apparatus for a spatial filtering technique for selecting only target terminals located at a certain distance from a plurality of objects by using a difference between transmission delay times of a radio wave signal and a sound wave signal. The user terminal transmits a sound wave signal to the neighboring terminals to the neighboring terminals in order to select terminals among the neighboring terminals whose distance from the user terminal corresponds to the distance from the user terminal to the target terminal, and after a preset transmission time delay. The radio signal is transmitted to the neighboring terminals. Receive response signals from neighboring terminals having a sound wave signal and a neighboring terminal, which receive the radio wave signal, from which the distance from the user terminal falls within a preset range. The neighboring terminal receives the sound wave signal from the user terminal, and receives the radio wave signal transmitted after the preset transmission time delay from the user terminal using the distance from the user terminal to the target terminal. It is determined whether the target terminal corresponds to the target terminal using the difference in the reception time between the sound wave signal and the radio signals from the user terminal to the neighboring terminals.