User Identification by Signature Code for Noisy Multiple-Access Adder Channel

User identification by signature code is considered for noisy multiple-access adder channel. An n/2-decodable signature code is developed from a Hadamard matrix of order n. The code is used to identify users through the multiple-access adder channel even in the presence of channel noise. A decoding rule is provided to correct lfloor(n/2 - 1)/2rfloor errors and then to identify users