  The problem of distributed access of a set of N on-off channels by K<N users
is considered. The channels are slotted and modeled as independent but not
necessarily identical alternating renewal processes. Each user decides to
either observe or transmit at the beginning of every slot. A transmission is
successful only if the channel is at the on state and there is only one user
transmitting. When a user observes, it identifies whether a transmission would
have been successful had it decided to transmit. A distributed learning and
access policy referred to as alternating sensing and access (ASA) is proposed.
It is shown that ASA has finite expected regret when compared with the optimal
centralized scheme with fixed channel allocation.
