—In wireless communication systems, the signal strength/quality generally varies with the distances between transmitters and receivers. As a consequence, the throughput in the MAC layer (or the transmission data rate in the PHY layer) also varies accordingly. In this paper, we call this phenomenon as the rate-distance nature of the wireless communications. Inspired by our success in the study of the random distances between nodes in the wireless ad hoc networks, we pioneer employing the distance-related concept to study the rate-distance nature of the multiple access protocols. By selecting slotted Aloha as a pilot multiple access protocol, we successfully analyze and demonstrate the rate-distance adaptability of slotted Aloha with finite and infinite populations. We also demonstrate how the ratedistance concept can be applied to the rate adaptation of the MAC protocol in the cognitive radio.