Doppler Tolerance, Complementary Code Sets and the Generalized   Thue-Morse Sequence
  We generalize the construction of Doppler-tolerant Golay complementary waveforms by Pezeshki-Calderbank-Moran-Howard to complementary code sets having more than two codes. This is accomplished by exploiting number-theoretic results involving the sum-of-digits function, equal sums of like powers, and a generalization to more than two symbols of the classical two-symbol Prouhet-Thue-Morse sequence. 
Hieu D. Nguyen and Greg E. Coxson
cs.IT math.IT