An Energy-efficient Technique for Constrained Application Protocol of Internet of Things

The CoRE Working Group has proposed a resource directory (RD) in the centralized resource discovery of the constrained application protocol (CoAP). This directory contains a description for resources held in the servers, in which the servers register their resources in the RD while the clients are allowed to perform a lookup operation on these resources, and ask for any resource using single request. In order of making the resource directory fully updated, all nodes are periodically sending update messages (after fixed period of time) to the RD contains the latest status of their information, these update messages will result in extra signaling overhead and consume more power from node's battery, this will drain the batteries and reduce the overall network lifetime. We have proposed a dynamic tuning technique to adjust the update message interval in CoAP, the proposed algorithm is depending on the battery level of the sending node, in which the update interval increased as battery level decreased. The results of experiments show that the dynamic approach can extend the network lifetime by 25%.