Contents I. Introduction
Recently, random access (RA) techniques have received much interest as various machine-to-machine (M2M) communications emerged, supporting a massive number of uncoordinated nodes in a network. The RA is also expected to play an important role in realizing internet-of-things (IoT) which connects a massive number of machine nodes in a wide range of applications such as smart metering, surveillance, security, infrastructure management, city automation, and e-health. Among various RA techniques, slotted ALOHA is a simple and widely used scheme [1]. The maximum throughput efficiency of slotted ALOHA is known to be for large , where denotes the number of nodes in a network. In the slotted ALOHA protocol, collided packets at an access point (AP) are simply discarded.
