Patent ID: 8184728

Claim:
A method for sidelobe suppression in an orthogonal frequency division multiplexing (OFDM) based cognitive system, the method comprising: scanning an operation band of the cognitive system to detect at least one current licensed user operating in the operation band, each of the detected current licensed users having a corresponding center frequency and a corresponding bandwidth; disabling a plurality of subcarriers associated with each of the current licensed users, the subcarriers disabled based upon the corresponding center frequency and corresponding bandwidth of each of the current licensed users; creating an index of the disabled subcarriers, the index comprising the center frequency and bandwidth for each of the current licensed users; receiving a current time domain OFDM symbol to be transmitted over a set of active subcarriers in the operation band, the current OFDM symbol comprising current modulated data; receiving a next time domain OFDM symbol to be transmitted over the set of active subcarriers in the operation band, the next time domain OFDM symbol comprising next modulated data; calculating an OFDM symbol extension to be added to the received current OFDM symbol, the OFDM symbol extension calculated based upon the set of active subcarriers, the index of the disabled subcarriers, the current modulated data of the current OFDM symbol, the next modulated data of the next OFDM symbol and a desired symbol extension length; and extending the current OFDM symbol using the calculated OFDM symbol extension to suppress the sidelobes of the OFDM symbols and reduce interference to the current licensed users.