Study On Application Layer Protocols In Wireless Sensor And Actor Networks

The Wireless Sensor and Actor Network (WSAN) is an important part of the Internet of Things (IoT), it provides an important sensing and control interface to the physical world in the IoT, and has been widely studied and applied in the academic and industrial fields.The WSAN system has a variety of application scenarios and functional requirements. The system processing logic and hierarchy are closely related to the application layer protocol. A well-designed application layer protocol can improve the efficiency of the system effectively. Therefore, the study of application layer protocol for the WSAN has the profound research and practical significances.We study the WSAN application layer protocol from three parts in this paper:the studies of application layer protocols on the architecture, evaluation etc; the study of application layer protocol for environmental monitoring; and the study of application layer protocol for intelligent buildings.1. We focus on the architecture, evaluation of application layer protocols. In detail, we first analyse two kinds of WSAN application layer protocols, named MQTT-SN and CoAP, which have been well-studied. Then we divide the protocols into two categories from the architecture perspective, named "front distributed" and "back-end centralized" architectures. Finally, the evaluation indicators of WSAN systems and application scenarios of the protocols are shown.2. We study the application layer protocol in environmental monitoring. In the environmental monitoring, a "back-end centralized" WSAN system framework is proposed by using the MQTT-SN protocol and IPv6/6LoWPAN technology. Comparing with the CoAP scheme, the theoretical analysis and experimental results show that the proposed scheme performs better in many aspects.3. We design an application layer protocol for intelligent building. In the intelligent buildings, a hybrid WSAN application framework with the "front-end distributed" and "centralized back-end" is designed and implemented. Comparing with the CoAP scheme and MQTT-SN scheme, the theoretical analysis and experimental results show that the proposed scheme achieves better performance in intelligent buildings scenarios and can solve some problems in the MQTT-SN and CoAP schemes.