A computationally efficient PAPR reduction scheme for STBC-OFDM systems

This paper proposes an efficient low-complexity cross-antenna rotation and inversion (CARI) scheme based on enhanced parallel tabu search (TS) for the reduction of peak-to-average power ratio (PAPR) in space-time block-coded orthogonal frequency-division multiplexing (STBC-OFDM) systems. CARI is an efficient PAPR reduction technique that fully utilizes additional degrees of freedom provided by employing multiple transmit antennas. The optimal CARI scheme, however, requires an exhaustive search over all possible combinations of subblockwise CARI, whose computational complexity (CC) increases exponentially with the number of subblocks. To reduce the CC while offering low PAPR, this paper formulates a new combinatorial optimization problem for the PAPR reduction with the CARI technique, and then proposes using enhanced parallel TS to search for an optimal combination of subblockwise CARI. Simulation results reveal that the proposed parallel TS-based scheme can have a PAPR only 0.0068 dB higher than that of the optimal CARI scheme, while its computation load is only 3.0518% of the optimal scheme. This demonstrates that the proposed scheme can be an efficient alternative method to greatly reduce the CC while retaining significant PAPR reduction of STBC-OFDM signals.