Self-Organized Low-Power Multihop Failover Protocol for a Cellular-Based Public Safety Device Network

This study proposes a network failover protocol for public safety devices, such as fire alarms and gas leak detectors using a cellular (i.e., 5G and LTE) Internet of Things (IoT) network, and evaluates its performance through experiments. The proposed protocol recovers communication functions by establishing a detour route through the secondary network (i.e., 447-MHz narrowband wireless network) when a problem occurs in the primary network (i.e., cellular network) in a disaster situation. All operations of the proposed protocol are performed autonomously by self-organization and collaboration of distributed nodes without centralized control. Thus, the communication function is maintained until all physically configurable routes are cut without any network reconfiguration process, even under adverse conditions, where nodes and communication paths status frequently change in real time due to a disaster. In addition, this failover protocol reduces power consumption by activating the secondary network only at the moment when network failover is necessary by using the novel self-organized low-power multihop relay wake-up scheme proposed in this study. Therefore, the proposed protocol can be easily applied to IoT devices that are often operated only by batteries. The proposed protocol also has the advantage of immediate use without any modification of the current cellular IoT network.