An information-spectrum approach to capacity theorems for the general multiple-access channel

The paper deals with the capacity problems for the general multiple-access channel, where the channel transition probabilities are arbitrary for every blocklength n. The approach used here, which is called the information-spectrum approach, is quite different from the standard typical-sequence and/or AEP techniques. The general formula for the capacity region for the general multiple-access channel is thus established. In order to examine the potentiality, we apply it to the mixed channel to obtain the formula for its capacity region. The case where input cost constraints are imposed is also considered.