The relationships among data symbols satisfied for sidelobe suppression in MB-OFDM cognitive radios

From the mathematic expression, we can see that sidelobe power of multi-band orthogonal frequency-division multiplexing (MB-OFDM) signal is a function of the data symbols loaded on the sub-carriers. Through the derivation of the minimum of the function, relationships among data symbols, which help to suppress sidelobes, are obtained. Two types of methods, referred as sub-carrier adding (SA) method and sub-carrier multiplying (SM) method, are proposed, which realize the relationships at the cost of small degradation in information transmission rate. As a result, with the proposed methods, the sidelobe power can be suppressed. Simulation results also prove this.