Scheduling updates from remote sensors is a key task for the internet of things (IoT). In this context, the mathematical concept of age of information is often used to capture the freshness of received data. This is, in turn, relevant to optimize the frequency of the exchanges, especially for resource constrained (e.g., energy-limited) sensors. Most investigations on the subject assume that the transmitter can leverage knowledge of the age of information at the receiver side to decide when to send data, even when the communication channel is unreliable. In reality, tracking the outcome of the updates would require additional consumption of resources to acquire a feedback. We investigate the optimal schedule of updates over a finite time horizon for a resource-constrained sensor that is allowed to perform a limited number of updates, as typical of IoT devices. We discuss the role of the feedback from the receiver, and whether it is convenient to ask for it whenever this causes additional energy consumption and consequently allows the transmission of a lower number of updates. We analytically identify regions for the feedback cost and the reliability of the channel where making use of feedback may or may not be beneficial.
翻译:远程传感器的时间安排更新是事物互联网(IoT)的一项关键任务。在这方面,信息年龄的数学概念常常被用来捕捉所收到数据的新鲜度,这反过来又与优化交换频率,特别是资源受限(例如能源受限)传感器的交流频率有关。关于这一主题的大多数调查都假定,发射机能够利用接收方对信息年龄的了解来决定何时发送数据,即使通信渠道不可靠。在现实中,跟踪更新的结果需要额外的资源消耗才能获得反馈。我们调查一个资源受限制的传感器在有限的时间范围内进行有限的更新的最佳时间表,这种更新可以作为IoT装置的典型。我们讨论接收器反馈的作用,以及一旦造成额外的能源消耗,以及因此允许传递较少的更新信息是否方便。我们分析确定反馈成本的区域以及利用反馈可能或可能无益的频道的可靠性。