This paper studies information timeliness in multi-source wireless Internet of Things (IoT) status updating systems under a truncated Automatic Repeat reQuest (ARQ) protocol. We propose a source-aware truncated ARQ (SATARQ) scheme that allows differentiated maximum transmission times (MTTs) tailored to different sources. This work focuses on a wireless system with preemptive update management. To study the statistical characteristics of the age of information (AoI) process for each source, a multi-dimensional age process (MDAP) is developed and modeled as a Markov chain, tracking both the AoI and the age of the concerned source's update currently in transmission. Via Markov analysis of the MDAP, we obtain analytical expressions for the distributions and averages of the AoI and peak AoI, as well as the average power consumption of IoT device. The timeliness-energy tradeoff is analyzed by examining the impact of the MTT, update generation probability (UGP), and wireless transmission power (TP). Moreover, this work explores the energy efficiency of the wireless status updating process and its relationship with the information timeliness and energy cost. Numerical results validate the theoretical analysis. Finally, it is demonstrated that the proposed SATARQ, combined with the optimization of MTTs, UGPs, and TPs, significantly improves the overall timeliness-energy tradeoff and energy efficiency across all sources.

翻译：本文研究了截断自动重传请求（ARQ）协议下多源无线物联网（IoT）状态更新系统中的信息时效性。我们提出了一种基于源感知的截断ARQ（SATARQ）方案，该方案允许根据不同源定制差异化的最大传输次数（MTT）。本文重点关注采用抢占式更新管理的无线系统。为研究各源的信息年龄（AoI）过程的统计特性，我们构建了一个多维年龄过程（MDAP）并将其建模为马尔可夫链，该链同步追踪AoI及当前传输中相关源更新的年龄。通过对MDAP的马尔可夫分析，我们推导出AoI与峰值AoI的分布和均值，以及物联网设备平均功耗的解析表达式。通过考察MTT、更新生成概率（UGP）和无线发射功率（TP）的影响，分析了时效性-能耗权衡。此外，本文探讨了无线状态更新过程的能量效率及其与信息时效性和能量成本的关系。数值结果验证了理论分析的正确性。最后证明，所提出的SATARQ结合MTT、UGP和TP的优化，显著改善了所有源的整体时效性-能耗权衡及能量效率。