Simulation Study of Dynamic Observing Period Adjustment for CoAP-based Monitoring Systems

Objectives: This paper is a simulation study of dynamic observing period adjustment (DOPA) to determine the appropriate DOPA stage value that prevents the buffer overflow in various constrained application protocol (CoAP) based monitoring systems. Methods/Statistical Analysis: To determine the appropriate DOPA stage value for various CoAP-based monitoring systems, we set a variety of simulation scenarios that use different values of simulation parameters and investigate the number of successful transmissions and dropped messages of each simulation. Then, we determine the appropriate DOPA stage value of each scenario, which prevents buffer overflow and maximizes the number of successful transmissions simultaneously. Findings: The experimental simulation is conducted under various simulation scenarios. The simulation results show that the appropriate DOPA stage value increases as the number of devices or payload size increases. It also increases when the observing period of servers or clock rate decreases. The correlations between the DOPA stage value and simulation parameters are obtained through these results, which is used for determining the appropriate DOPA stage value. Improvements/Applications: Our study can be used to provide an optimal observing period for buffer overflow prevention in various monitoring systems.