Imagine I have a $N$-dimensional hypercube.  My aim is to distinctly color as many non-overlapping $k$-hop neighborhoods as possible (i.e. sets of vertices connected by a Manhattan distance of at most $k$).  What is the maximum number of non-overlapping neighborhoods, $Q$, that can be distinctly colored?   

Is an optimum solution for $Q$, or a tight bound known for certain values of $k$?  

Motivation: It is my understanding (which may be in error) that if we set $k =$ Ceiling[$\frac{d}{2}$], then $Q$ is the maximum size of a family of strings have a pairwise Hamming distance greater than $d$.  I imagine this can be abstracted to larger alphabet sizes $q>2$ (i.e. $(N,q)$ Grey codes).  If this is wrong, please do let me know.