Subspace Subcodes of Reed-Solomon Codes

space subcode of a Reed-Solomon (SSRS) code Over GF(2"') is the set of RS codewords, whose components all lie in a particular GF(2)subspace of GF(2"). SSRS codes include both generalized B C H codes and "trace-shortened" Rs codes [2][3] as special casea. In this paper we present an explicit formula for t h e dimension of an arbitrary RS subspace subcode. Using this formula, we And that in many cases, SSRS codes are competetive with algebraic geometry codes, and that in some cnsea, the dimension of the best subspace subcode is larger than that of the corresponding GBCH code.