WiSEGATE: Wireless Sensor Network Gateway framework for internet of things

With internet of things vision, computing systems get the ubiquity of real world. Wireless Sensor Network (WSN) technology plays a critical role for the construction of this paradigm. Hence, WSN technology should be adapted to support interoperability with the commodity internet entities. Since technological background of WSN and IP networks do not fit each other, this effort is not a straightforward process. In this paper, we introduce WiSEGATE which addresses end-to-end reliable interconnection problem between multiple internet entities and sensor nodes. WiSEGATE is a prototype of a new web server which supports three tier service scheme with a data acquisition mechanism of WSN to access the physical data in particular locations in the real world. In WiSEGATE, an interconnection gateway handles operations required for the interoperability. Since this gateway maintains reliable TCP/IP connections of the interconnected entities, the resource constraint sensor nodes on WSN do not require a TCP/IP stack for handling end-to-end connections. A lightweight service layer is implemented on a sensor node for operations required by the interconnection. The strength and novelty of the model lies in the fact that this lightweight service layer relieves extra memory usage for end-to-end connection management. For determining limits of the proposed model, firstly, we examined the steps for request/response mechanism and modeled the gateway as a queueing system. By doing this, we derive a definition of the request traffic. For proof of concept, we performed comprehensive tests in simulation and real testbed environments for WLAN connection. WiSEGATE can achieve reasonable response times up to 80 simultaneous connections from remote entities to WSN when WLAN PER is less than 0.2.