Mika Mizutani

Efficient multiple gateway system for WSN management in BEMS

Among various application scenarios of Internet of Things (IoT) technology, Building Energy Management System (BEMS) is one of the most promising applications considering the sustainable development trend in the world. With progress of related technologies, the BEMS can gather more and more applications into itself. But the development also involves an issue which is huge data transferring and processing. This paper provides a multiple gateway system for wireless sensor network (WSN) management in BEMS, and also provides an efficient data transmission method for sensor data collection. The multiple gateway system includes at least a main gateway, several terminal gateway and more sensor nodes. These sensor nodes find a nearest terminal gateway and access to its LAN, and send data to it. The terminal gateway with a control module on it, can collect information of every neighbor gateway including gateway buffer size and distance to itself, and then optimize routing according to gateway information, and finally sends data to main gateway timely. The main gateway can process data like data fusion, and users can access these data via LAN or Internet. Using these multiple gateway system, the network power consumption and data delay can be both decreased, thereby promoting the system working efficiency.

A high speed protocol processor to boost gateway performance

The authors propose a high-speed protocol processor for gateways based on the following concept: normal data transfer is executed by special-purpose hardware and a general-purpose microprocessor handles abnormal data transfer and connection control. To analyze the quantitative effect of this proposal, a high-speed protocol processor which can execute OSI (open systems interconnection) layers two to four was manufactured, and its performance was measured. The protocol processing time for normal data transfer in the experimental system is 1/12 that of the conventional system on the transmission side and 1/7 that of the conventional system on the reception side. This result shows that application of the high-speed protocol processor in protocol-converting gateways is effective for improving performance.<<ETX>>