Abstract

A two-user Ricean fading multi-access channel is considered without state-information at the receiver or the transmitter. The sum-rate fading number is defined and it is shown that if neither specular component is zero, then it is strictly smaller than the fading number that would result if the users could fully cooperate. If one of the users is required to use circularly-symmetric signaling, then the fading number is achievable by time-sharing. The problem of computing the sum-rate fading number without this constraint is still open.