Cross-Entropy-Based Sign-Selection Algorithms for Peak-to-Average Power Ratio Reduction of OFDM Systems

Sign-selection uses a set of subcarrier signs to reduce the peak-to-average power ratio (PAR) of orthogonal-frequency-division multiplexing (OFDM). However, the computational complexity (worst-case) is exponential in , the number of subcarriers. Suboptimal sign-selection algorithms, achieving different tradeoffs between the PAR reduction and complexity, have thus been developed. For example, the derandomization method achieves high PAR reduction of (log ) with relatively high complexity of ( ). On the other hand, selective mapping (SLM) and partial transmit sequences (PTS) sacrifice the achievable PAR reduction for lower complexity. In this paper, we develop two new cross-entropy (CE)-based sign-selection algorithms. Our algorithms simultaneously updates the probabilities of the signs of all subcarriers. As shown in Section II-D, the first algorithm obtains a PAR lower than the above methods with a complexity level of ( ). However, if the number of iterations is fixed, this algorithm o...

• Type: Journal
• Year: 2008
• Where: TSP
• Authors: Luqing Wang, Chintha Tellambura
• Keywords: Algorithms, PAR Reduction, Subcarriers, TSP 2008