Construction of (N + M)-Direct codes in GF(2N)

A distance construction method for the class of T -Direct codes constituted by a set of T maximum rank distance (MRD) codes is proposed. The proposed distance construction is shown to increase the minimum distance of the constituent codes of T - Direct codes when employed. Further, a construction procedure is developed from the proposed distance construction. It is shown that the extended distance construction procedure increases the number of users (constituent codes) of a T -Direct code; when employed on an n-Direct code, it constructs a (2n - 1)-Direct code, thereby supporting more users in a multi-user environment.