Impact of loosely coupled data dissemination policies for resource challenged environments

A Cyber-Physical System (CPS) deployed to a resource-constrained environment can face multiple challenges like (i) no or limited network coverage, (ii) no or limited possibility of energy replenishment, (iii) no or limited physical access by humans, (iv) nodes must cope with environmental factors including avalanches, low temperatures, snow, ice, water and wild animals. Devices being part of such a CPS must be battery powered and be energy efficient to achieve long life-time. However, the CPS still has to disseminate data to increase resiliency, safely keep results or update nodes. A trade-off between energy spent and data dissemination needs to be found, ideally by minimizing the energy usage and maximizing the relevant data dissemination performance metrics. In this paper, we evaluate and discuss the efficiency (in energy, time and number of successful distributions) of multiple data distribution policies by mean of flow-level simulations. We report on the trade-off between (i) successful data dissemination and (ii) energy and uptime overheads resulting from the usage of loosely coupled policies. To fully explore the scope of possibilities, we simulate a wide range of scenarios extracted from real measurements and previous deployments. Characteristics of CPS devices developed by the Distributed Arctic Observatory (DAO) are used as simulation platforms. Results show that an efficient policy in a given scenario can perform worse in another scenario. We also show that simple policies, especially when combined, can help in minimizing the energy consumed by most of the devices composing the CPS and maximizing the relevant dissemination performance metrics.