A new bound for the zero-error capacity region of the two-user binary adder channel

A new uniquely decodable (UD) code pair for the two-user binary adder channel (BAC) is presented. This code pair leads to an improved bound for the zero-error capacity region of such a channel. The highest known rate for a UD code pair for the two-user BAC is thereby improved to (log/sub 2/240)/6/spl ap/1.3178. It is also demonstrated that the problem of finding UD code pairs for the closely related binary XOR channel is in one-to-one correspondence with a certain construction of binary one-error-correcting codes.