Having timely and fresh knowledge about the current state of information sources is critical in a variety of applications. In particular, a status update may arrive at the destination later than its generation time due to processing and communication delays. The freshness of the status update at the destination is captured by the notion of age of information. In this study, we analyze a multiple sensing network with multiple sources, multiple servers, and a monitor (destination). Each source corresponds to an independent piece of information and its age is measured individually. Given a particular source, the servers independently sense the source of information and send the status update to the monitor. We assume that updates arrive at the servers according to Poisson random processes. Each server sends its updates to the monitor through a direct link, which is modeled as a queue. The service time to transmit an update is considered to be an exponential random variable. We examine both homogeneous and heterogeneous service and arrival rates for the single-source case, and only homogeneous arrival and service rates for the multiple-source case. We derive a closed-form expression for the average age of information under a last-come-first-serve (LCFS) queue for a single source and arbitrary number of homogeneous servers. Using a recursive method, we derive the explicit average age of information for any number of sources and homogeneous servers. We also investigate heterogeneous servers and a single source, and present algorithms for finding the average age of information.
翻译:在各种应用中,及时掌握关于信息来源现状的最新知识至关重要。 特别是, 由于处理和通信延迟, 状态更新可能晚于其生成时间到达目的地。 信息年龄的概念反映了目的地状态更新的新鲜性。 在本研究中, 我们分析一个包含多种来源、 多个服务器和监视器( 目的地) 的多重感测网络。 每个来源都与独立的信息相匹配, 其年龄是单独测量的。 根据特定来源, 服务器独立感知信息来源, 并将状态更新发送给监视器。 我们假设更新会根据 Poisson 随机程序到达服务器。 每个服务器都通过直接链接向监测器发送更新, 直接链接以队列为模型。 传送更新的服务时间被视为一个指数性随机变量。 我们检查了单一来源、 多来源的单一服务和到达率, 并且只对多个来源的到达和服务率进行统一度。 我们为最后一服务对象( LCFS) 的中平均信息年龄, 我们为单一来源和任意的服务器的排序。 我们使用一个平均版本服务器的平均序列, 我们使用一个单一格式的服务器源和直观、 。