Abstract: Information theory is commonly used to find the performance limits of communication systems. The purpose of the first talk is to review those concepts from information theory that are needed to make the second talk accessible. I will cover the basic channel coding theorem and two common multiuser systems: 1) The multiple access channel, commonly used to model the uplink (mobile to base-station) of a cellular system, and 2) The broadcast channel, commonly used to model the downlink (base-station to mobile) of a cellular system.