论文标题
选择性编码政策，以最大化信息新鲜度
Selective Encoding Policies for Maximizing Information Freshness
论文作者
论文摘要
信息源从观察到的随机现象中生成独立且相同分布的状态更新消息，该现象基于给定的PMF采取$ n $不同的值。这些更新数据包在发送器节点上编码要发送到接收器节点，该节点希望以尽可能少的年龄跟踪观察到的随机变量。发射机节点实现了选择性$ K $编码策略，以至于发射器节点不是编码所有可能的$ n $实现，而是编码最可能的$ k $实现。我们考虑有关其余$ n-k $更少的可能实现的三种不同政策：$最高$ $ $ $ $ $ $ $ $ $ $ $编码$，每当从剩余的$ n-k $ values中实现实现时，它们都会无视； $随机$ $ $ $ $ $ $ $编码$编码并发送剩余的$ n-k $实现，具有一定概率，以进一步告知接收器节点，而牺牲了所选$ k $实现的较长代码；和$最高$ $ K $ $ $ $ $ $ $ $ $ $ $ $ $ $ a $ $ $ $ $ $ $ $符号$，当剩下的$ n-k $实现之一发生时，它会发送指定的空符号。对于所有这三个编码方案，我们找到了平均年龄并确定年龄在最佳的实际编码字长度，包括在后一个方案的情况下的空符号的代码字长度，以便将接收器节点处的平均年龄最小化。通过对任意PMF的数值评估，我们表明，这些选择性编码策略的平均年龄要比编码每个实现的平均年龄较低，并找到相应的年龄优势$ K $值。
An information source generates independent and identically distributed status update messages from an observed random phenomenon which takes $n$ distinct values based on a given pmf. These update packets are encoded at the transmitter node to be sent to a receiver node which wants to track the observed random variable with as little age as possible. The transmitter node implements a selective $k$ encoding policy such that rather than encoding all possible $n$ realizations, the transmitter node encodes the most probable $k$ realizations. We consider three different policies regarding the remaining $n-k$ less probable realizations: $highest$ $k$ $selective$ $encoding$ which disregards whenever a realization from the remaining $n-k$ values occurs; $randomized$ $selective$ $encoding$ which encodes and sends the remaining $n-k$ realizations with a certain probability to further inform the receiver node at the expense of longer codewords for the selected $k$ realizations; and $highest$ $k$ $selective$ $encoding$ $with$ $an$ $empty$ $symbol$ which sends a designated empty symbol when one of the remaining $n-k$ realizations occurs. For all of these three encoding schemes, we find the average age and determine the age-optimal real codeword lengths, including the codeword length for the empty symbol in the case of the latter scheme, such that the average age at the receiver node is minimized. Through numerical evaluations for arbitrary pmfs, we show that these selective encoding policies result in a lower average age than encoding every realization, and find the corresponding age-optimal $k$ values.
