Two Fundamental Algorithms for Reducing Peak-to-Average Power Ratio in OFDM Systems

In OFDM systems, two fundamental algorithms are available for reducing peak-to-average power ratio (PAPR): the Selective Mapping (SLM) algorithm and the Partial Transmit Sequence (PTS) algorithm. The Selective Mapping (SLM) algorithm operates in the time domain by applying phase rotation techniques, where different phase rotations modify the signal's peak values. Implementation typically involves generating multiple candidate signals with randomized phase sequences and selecting the one with minimum PAPR using a comparative evaluation function. Meanwhile, the Partial Transmit Sequence (PTS) algorithm works in the frequency domain by partitioning subcarriers into disjoint blocks and applying independent phase rotations to each block, effectively distributing peak energy across different subcarriers. This approach requires optimizing phase factors through search algorithms (e.g., iterative or combinatorial methods) to minimize PAPR. Consequently, when selecting between these algorithms, specific requirements and scenarios must be considered to achieve optimal performance and effectiveness, including computational complexity trade-offs and hardware implementation constraints.