The linear complexity of sequences with low autocorrelation from interleaved technique and period pq

In this paper, we consider the quaternary sequences with period pq where p and q are two odd primes. These sequences are constructed by interleaving the quaternary power residue sequence of period p according to the quadratic residue with respect to q. We derive the linear complexity of these sequences over the finite field of order four and the finite ring of order four. It is shown that the considered quaternary sequences have a sufficiently large linear complexity to resist Berlekamp-Massey algorithm or Reeds and Sloane algorithm attack effectively.