On the intersection of ℤ2ℤ4-additive Hadamard codes

The intersection structure for ℤ2ℤ4 -additive Hadamard codes is investigated. For any two of these codes C1 C2, the Abelian group structure of the intersection C1 ∩ C2 is characterized. The parameters of this Abelian group structure corresponding to the intersection codes are computed, establishing lower and upper bounds for them. Constructions are given of codes whose intersection has any parameters between these bounds. Finally, the intersection problem, i.e., what the possibilities are for the number of codewords in the intersection of two ℤ2 ℤ4-additive Hadamard codes C1 and C2 being of the same length, is also studied. Lower and upper bounds for the intersection number are established and, for any value between these bounds, codes with this intersection value are constructed. © 2009 IEEE.