Aggregation and scheduling in CoAP/Observe based wireless sensor networks

Wireless sensor networks (WSNs) gained worldwide attention and already have a high impact on our societies. For next generation WSNs one of the challenges was to integrate IPv6 over such very constrained networks, a standardization process already in progress. Together with this, the constraint application protocol (CoAP), and then the Observe extension, were proposed for RESTful services to be provided. The observing capabilities of CoAP/Observe, together with the possibility of using proxies, raise optimization issues when there are multiple notification requests in a network. These issues involve deciding which registration steps to be done, while keeping consistency of data, so that energy is saved. In this article a framework is proposed for the planning of such registration steps, together with the aggregation and scheduling of notification deliveries at proxies, so that energy saving is maximized, bandwidth is used efficiently and the overall delay is reduced.