Joint Assignment and Scheduling for Minimizing Age of Correlated Information

Age of information has been recently proposed to quantify the freshness of information, e.g., in cyber-physical systems, where it is of critical importance. Motivated by wireless camera networks where multi-view image processing is required, in this paper we propose to extend the concept of age of information to capture packets carrying correlated data. We consider a system consisting of wireless camera nodes with overlapping fields of view and a set of processing nodes, and address the problem of the joint optimization of processing node assignment and camera transmission scheduling, so as to minimize the maximum peak age of information from all sources. We formulate the multi-view age minimization (MVAM) problem, and prove its NP-hardness under the two widely used interference models as well as with given candidate transmitting groups. We provide fundamental results including tractable cases and optimality conditions of the MVAM problem for two baseline scenarios. To solve MVAM efficiently, we develop an optimization algorithm based on a decomposition approach. Numerical results show that by employing our approach the maximum peak age is significantly reduced in comparison to a traditional centralized solution with minimum-time scheduling.