Age of information (AoI) is an effective performance metric measuring the freshness of information and is particularly suitable for applications involving status update. In this paper, using the age violation probability as the metric, scheduling for heterogeneous multi-source systems is studied. Two queueing disciplines, namely the infinite packet queueing discipline and the single packet queueing discipline, are considered for scheduling packets within each source. A generalized round-robin (GRR) scheduling policy is then proposed to schedule the sources. Bounds on the exponential decay rate of the age violation probability for the proposed GRR scheduling policy under each queueing discipline are rigorously analyzed. Simulation results are provided, which show that the proposed GRR scheduling policy can efficiently serve many sources with heterogeneous arrivals and that our bounds can capture the true decay rate quite accurately. When specialized to the homogeneous source setting, the analysis concretizes the common belief that the single packet queueing discipline has a better AoI performance than the infinite packet queueing discipline. Moreover, simulations on this special case reveals that under the proposed scheduling policy, the two disciplines would have similar asymptotic performance when the inter-arrival time is much larger than the total transmission time.

翻译：信息年龄（AoI）是衡量信息新鲜度的有效性能指标，特别适用于涉及状态更新的应用场景。本文以年龄违规概率为指标，研究异构多源系统的调度问题。针对各源内数据包调度，分别考虑无限数据包排队规程和单数据包排队规程两种队列规则。进而提出一种广义轮询（GRR）调度策略对多源进行调度。严格分析了两种排队规程下所提GRR调度策略年龄违规概率的指数衰减率界限。仿真结果表明，所提GRR调度策略能高效服务具有异构到达特征的多源系统，且所推导的界限能较为准确地刻画真实衰减率。在特化为同构源场景时，分析证实了单数据包排队规程在AoI性能上优于无限数据包排队规程的普遍认知。此外，针对该特例的仿真揭示：在所提调度策略下，当数据包到达间隔时间远大于总传输时间时，两种规程具有相似的渐近性能。