This paper considers a communication system where a source sends time-sensitive information to its destination via queues in tandem. We assume that the arrival process as well as the service process (of each server) are memoryless, and each of the servers has no buffer. For this setup, we develop a recursive framework to characterize the mean peak age of information (PAoI) under preemptive and non-preemptive policies with $N$ servers having different service rates. For the preemptive case, the proposed framework also allows to obtain mean age of information (AoI).

翻译：本文考虑一个通信系统，其中信源通过串联队列将时效敏感信息发送至目的地。我们假设到达过程及（每个服务器的）服务过程均无记忆性，且每个服务器均无缓冲区。针对该场景，我们建立了一个递归框架，以刻画在包含N个不同服务速率服务器的系统中，采用抢占式与非抢占式策略下的平均信息峰值年龄（PAoI）。对于抢占式情形，该框架还可用于获取平均信息年龄（AoI）。