Upper bound for uniquely decodable codes in a binary input N-user adder channel

Abstract

The binary input N-user adder channel models a communication media accessed simultaneously by N users. Each user transmits a binary codeword of length n chosen from its codebook and the channel output consists of a componentwise arithmetic sum of the binary digits. Van Tilborg (1978) gave an upper bound on the size of a uniquely decodable code for the two-user case. His work is generalized here to the N-user case. The results give interesting information on the existence and properties of such codes.