  Low-coherence sequences with low peak-to-average power ratio (PAPR) are
crucial for multi-carrier wireless communication systems and are used for
pilots, spreading sequences, and so on. This letter proposes an efficient
low-coherence sequence design algorithm (LOCEDA) that can generate any number
of sequences of any length that satisfy user-defined PAPR constraints while
supporting flexible subcarrier assignments in orthogonal frequency-division
multiple access (OFDMA) systems. We first visualize the low-coherence sequence
design problem under PAPR constraints as resolving collisions between
hyperspheres. By iteratively adjusting the radii and positions of these
hyperspheres, we effectively generate low-coherence sequences that strictly
satisfy the imposed PAPR constraints. Simulation results (i) confirm that
LOCEDA outperforms existing methods, (ii) demonstrate its flexibility, and
(iii) highlight its potential for various application scenarios.
