2 research outputs found
Optimal Scheduling Policy for Minimizing Age of Information with a Relay
We consider IoT sensor network where multiple sensors are connected to
corresponding destination nodes via a relay. Thus, the relay schedules sensors
to sample and destination nodes to update. The relay can select multiple
sensors and destination nodes in each time. In order to minimize average
weighted sum AoI, joint optimization of sampling and updating policy of the
relay is investigated. For errorless and symmetric case where weights are
equally given, necessary and sufficient conditions for optimality is found.
Using this result, we obtain that the minimum average sum AoI in a closed-form
expression which can be interpreted as fundamental limit of sum AoI in a single
relay network. Also, for error-prone and symmetric case, we have proved that
greedy policy achieves the minimum average sum AoI at the destination nodes.
For general case, we have proposed scheduling policy obtained via reinforcement
learning.Comment: 30 page
Minimizing the AoI in Resource-Constrained Multi-Source Relaying Systems: Dynamic and Learning-based Scheduling
We consider a multi-source relaying system where the independent sources
randomly generate status update packets which are sent to the destination with
the aid of a relay through unreliable links. We develop transmission scheduling
policies to minimize the sum average age of information (AoI) subject to
transmission capacity and long-run average resource constraints. We formulate a
stochastic control optimization problem. To solve the problem, a constrained
Markov decision process (CMDP) approach and a drift-plus-penalty method are
proposed. The CMDP problem is solved by transforming it into an MDP problem
using the Lagrangian relaxation method. We theoretically analyze the structure
of optimal policies for the MDP problem and subsequently propose a
structure-aware algorithm that returns a practical near-optimal policy. By the
drift-plus-penalty method, we devise a dynamic near-optimal low-complexity
policy. We also develop a model-free deep reinforcement learning policy, which
does not require the full knowledge of system statistics. To do so, we employ
the Lyapunov optimization theory and a dueling double deep Q-network.
Simulation results are provided to assess the performance of our policies and
validate the theoretical results. The results show up to 91% performance
improvement compared to a baseline policy.Comment: 30 Pages, preliminary results of this paper were presented at IEEE
Globecom 2021, https://ieeexplore.ieee.org/document/968594