  In this paper, we derive a Singleton bound for lattice schemes and obtain
Singleton bounds known for binary codes and subspace codes as special cases. It
is shown that the modular structure affects the strength of the Singleton
bound. We also obtain a new upper bound on the code size for non-constant
dimension codes. The plots of this bound along with plots of the code sizes of
known non-constant dimension codes in the literature reveal that our bound is
tight for certain parameters of the code.
