Age-Optimal Scheduling Over Hybrid Channels
Age-Optimal Scheduling Over Hybrid Channels
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DOI：
10.1109/tmc.2022.3205292
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发表时间：
2020-12
影响因子：
7.9
通讯作者：
Jiayu Pan;A. Bedewy;Yin Sun;N. Shroff
中科院分区：
文献类型：
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作者：
Jiayu Pan;A. Bedewy;Yin Sun;N. Shroff
我们考虑的问题时，一个源可以在两个异构的信道传输状态更新的信息年龄最小化。我们的工作受到5G毫米波技术的最新发展的激励，其中传输可能发生在不可靠但快速的（例如，毫米波）信道或慢可靠（例如，sub-6 GHz）信道。当信道处于“ON”状态时，不可靠信道被建模为处于高速率的时间相关的Gilbert-Elliot信道。可靠信道提供确定性但较低的数据速率。调度策略确定在每个时隙中用于传输的信道，旨在最小化信息的时间平均年龄（AoI）。最优调度问题被公式化为马尔可夫决策过程（MDP），这是具有挑战性的解决，因为超模块化不持有的状态空间的一部分。我们解决这一挑战，并表明，多维阈值型调度策略是最佳的年龄最小化。通过利用MDP的结构和分析的阈值型策略的离散时间马尔可夫链（DTMC），我们设计了一个低复杂度的二分法计算的最佳阈值。我们比较不同的调度策略，使用数值模拟。
We consider the problem of minimizing the age of information when a source can transmit status updates over two heterogeneous channels. Our work is motivated by recent developments in 5 G mmWave technology, where transmissions may occur over an unreliable but fast (e.g., mmWave) channel or a slow reliable (e.g., sub-6 GHz) channel. The unreliable channel is modeled as a time-correlated Gilbert-Elliot channel at a high rate when the channel is in the “ON” state. The reliable channel provides a deterministic but lower data rate. The scheduling strategy determines the channel to be used for transmission in each time slot, aiming to minimize the time-average age of information (AoI). The optimal scheduling problem is formulated as a Markov Decision Process (MDP), which is challenging to solve because super-modularity does not hold in a part of the state space. We address this challenge and show that a multi-dimensional threshold-type scheduling policy is optimal for minimizing the age. By exploiting the structure of the MDP and analyzing the discrete time Markov chains (DTMCs) of the threshold-type policy, we devise a low-complexity bisection algorithm to compute the optimal thresholds. We compare different scheduling policies using numerical simulations.