Error Exponent for Discrete Memoryless Multiple-Access Channels

This work addresses the problem of analyzing the best possible systems for communicating over a multiple-access channel (MAC) without feedback in the discrete memoryless setting. We consider the error exponents for this channel model and obtain upper and lower bounds on the channel reliability function. In particular, a unified framework to obtain all known upper and lower bounds on the reliability function of a point-to-point discrete memoryless channel is developed. By using a similar idea with a two-user discrete memoryless multiple-access channel, three lower bounds and two upper hounds on the reliability function are derived. To obtain upper bounds on the reliability function for DM-MACS, we formally characterize the typicality graph and look at some subgraph containment problems. Finally, a method to derive new bounds on the average/maximal error exponent by using known bounds on the maximal/average error exponent is obtained.