As the demand for low-latency services grows, ensuring the delay performance of random access (RA) networks has become a priority. Existing studies on the queueing delay of the Aloha model universally treat packets as atomic transmission units, focusing on delay measured in time slots. However, the impact of packetization on queueing delay has been overlooked, particularly for the mean queueing delay measured in seconds. Here, packetization refers to the process of determining the number of bits assembled into a packet. This paper establishes the mathematical relationship between packetization and mean queueing delay in seconds for connection-free and connection-based Aloha schemes, and explores the optimal packetization to minimize the queueing delay. We identify the optimal packetization and its corresponding minimum mean queueing delay via numerical methods, and analyze the influence of various network parameters. We further use simulations to investigate the impact of packetization on jitter of queueing delay. We then apply our analysis to re-evaluate the trade-off between the connection-free and connection-based schemes through the perspective of packetization. Furthermore, we apply the analysis to Random Access-Based Small Data Transmission (RA-SDT) in Non-Terrestrial Network (NTN) scenarios as a case study.

翻译：随着低延迟服务需求的增长，确保随机接入网络的时延性能已成为优先事项。现有关于Aloha模型排队时延的研究普遍将数据包视为原子传输单元，重点分析以时隙为单位的时延度量。然而，数据包化对排队时延的影响——尤其是以秒为单位的平均排队时延——长期被忽视。此处数据包化特指确定每个数据包所封装比特数的过程。本文建立了无连接型与基于连接型Aloha协议中数据包化与平均排队时延（以秒为单位）之间的数学关系，并探索使排队时延最小化的最优数据包化方案。我们通过数值方法确定了最优数据包化方案及其对应的最小平均排队时延，分析了各类网络参数的影响，并利用仿真进一步研究了数据包化对排队时延抖动的效应。进而将分析结果应用于从数据包化视角重新评估无连接型与基于连接型协议的性能权衡，最后以非地面网络场景中基于随机接入的小数据传输（RA-SDT）为例进行案例研究。