Linear codes from projective spaces

The linear code C-s,C- (t)(n,q) of s-spaces and t-spaces in a projective space PG(n,q), q = p(h), p prime, is defined as the vector space spanned over F-p by the rows of the incidence matrix of s-spaces and t-spaces. This code generalises the code of points and lines in a projective plane, which has been intensively studied since the 1970's. In this paper, we give an overview of what is currently known about the codes C-s,C-t(n,q) and their duals