Abstract
Cognitive radio technology with orthogonal frequency-division multiplexing provides great flexibility in spectrum utilization. An efficient adaptive search algorithm for computing subcarrier phase adjustments is proposed in this paper. This algorithm leads to coherent cancellation of subcarriers, and hence peak-to-average power ratio (PAPR) reduction. In traditional subcarrier phase adjustment techniques for PAPR reduction, there is a need to send a large amount of side information that may deteriorate the system throughput. On the other hand, the proposed algorithm sets the side information adaptively with an updating phase vector. Simulation results reveal that the proposed algorithm achieves a large PAPR reduction for a wide range of operating conditions as the traditional algorithms, while reducing the amount of side information. This side information reduction is attributed to the independency of the side information of the number subcarriers.