On Four-Valued Niho-Type Cross-Correlation Functions of $m$-Sequences
Kalle Ranto, Petri Rosendahl · IEEE Transactions on Information Theory · 2006
Consider the cross-correlation function Cd(tau) between two m-sequences of period p2k-1 that differ by a decimation d. Assume that d is of Niho type and Cd(tau) is four-valued. In this correspondence, the values of Cd(tau) are described. If p=2 then the values of Cd(tau) are -1-2k,-1,-1+2k, and -1+2k+jfor some integer j>0 for which 2j divides k. If p>2 then the values are -1-pk,-1,-1+pk, and -1+2middotpk