Method and system for fast detecting primary user during ongoing opportunistic transmission in OFDM-based cognitive radio

摘要

The present invention relates to a fast main user detection method and system during opportunistic transmission of a secondary user in an OFDM-based cognitive radio, wherein a fast main user detection method during opportunistic transmission of a secondary user in an OFDM- A secondary user transmit / receive terminal having two antennas periodically inserts a null symbol for a predetermined length of time into a predefined carrier wave among a plurality of carriers to transmit an OFDM-based cognitive radio signal through a first antenna A step of receiving and detecting a PU signal which is a carrier signal transmitted from a main user transmission / reception terminal through a second antenna in a null symbol interval, and detecting a PU signal, and when the PU signal is detected, And stopping transmission of the OFDM-based perceptual radio signal transmitted via the antenna. According to the present invention, the main user's channel signal can be quickly detected with less overhead and fewer additional devices than the conventional main user detection technique.