  In this paper, the 2-adic complexity of a class of balanced Whiteman
generalized cyclotomic sequences of period $pq$ is considered. Through
calculating the determinant of the circulant matrix constructed by one of these
sequences, we derive a lower bound on the 2-adic complexity of the
corresponding sequence, which further expands our previous work (Zhao C, Sun Y
and Yan T. Study on 2-adic complexity of a class of balanced generalized
cyclotomic sequences. Journal of Cryptologic Research,6(4):455-462, 2019). The
result shows that the 2-adic complexity of this class of sequences is large
enough to resist the attack of the rational approximation algorithm(RAA) for
feedback with carry shift registers(FCSRs), i.e., it is in fact lower bounded
by $pq-p-q-1$, which is far larger than one half of the period of the
sequences. Particularly, the 2-adic complexity is maximal if suitable
parameters are chosen.
