In OFDM (Orthogonal Frequency Division Multiplexing)-based wireless systems, when we employ an array antenna at receive side, SDMA (Space Division Multiple Access) can be easily realized by assigning different spectral positions of virtual subcarriers to different users. In this research project, we show the principle of VISA and evaluate the BER (Bit Error Rate) performance with measured 5GHz band data. VISA A B OFDM OFDM A B A A B B B A VISA 2 Reception of OFDM Signal A OFDM Signal A OFDM Signal B Reception of OFDM Signal B OFDM Signal A OFDM Signal B Reception of OFDM Signal A OFDM Signal A OFDM Signal B Reception of OFDM Signal B OFDM Signal A OFDM Signal B f A Virtual Subcarrier Position A B Virtual Subcarrier Position B f OFDM Signal A OFDM Signal B Receiver f A Virtual Subcarrier Position A B Virtual Subcarrier Position B f OFDM Signal A OFDM Signal B Receiver VISA VISA (1) VISA (2) VISA (3) VISA (1) VISA OFDM VISA 5GHz LAN IEEE802.11a VISA VISA VISA