Modeling and Performance Optimization of Slotted Aloha with Successive Transmission

Enabling massive access and data transmission in Internet of Things (IoT) scenarios remains a persistent challenge. An efficient medium access control (MAC) scheme is essential for addressing this issue. This paper proposes a MAC scheme named Slotted Aloha with Successive Transmission (SAST), where upon successful transmission of the Head-of-Line (HoL) packet, the node delivers remaining packets with probability 1 until a collision occurs, thereby capitalizing on immediate channel availability. By formulating a vacation queuing model, the access/data throughput and access delay are explicitly characterized and optimized by properly choosing the HoL packet transmission probability. It reveals that SAST achieves a maximum data throughput of 0.5, 37 % higher than e<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> in classic slotted Aloha. Practical insights are alos demonstrated through the example of 2-step small data transmission (SDT) random access in 5G. SAST can be seamlessly implemented into 5G, and compared to 2-step SDT scheme, SAST improves throughput performance while significantly reducing signaling overhead.