Gateway Adapters for Integrating Wireless Sensor Networks
Permanent address of the item is
Wireless sensor networks have grown more and more popular in the past few years. There are sensor networks available from several manufacturers. A wireless sensor network is usually tailored for a certain purpose and because of it's sensors, application specific radio range, data transfer speed, or other features it is unsuitable for other applications. In applications where several physical quantities are measured, it is hard to find one sensor network technology which would cover all of the requirements. Co-operative use of one or more different wireless sensor network technology is required in these applications. This thesis reports the design and prototype implementation of an adaptation layer for connecting several wireless sensor network technologies to the same gateway. An adaptation layer consists of technology specific adapters, which convert the technology specific measurement messages to one unified message format understood by the gateway. This makes it possible to use the measurement data similarly regardless of the sensor network it is from. This thesis presents adapter implementations for ZigBee, Z-Wave, and Bluetooth networks. The adapters are tested as a part of a larger ensemble, where the measurement data is used in cloud services. In addition this thesis introduces requirements for designing and implementing new sensor network adapters. The results of the thesis show that several different wireless sensor network technologies can be used co-operatively with an adaptation layer. The adaptation layer also separates the sensor network integrations to the gateway from the rest of the development, speeding up the development of the gateway and end-user services. In addition the adaptation layer makes applications independent of one sensor network manufacturer, and makes it easy to add and change sensor networks to already deployed applications. On the downside, the adaptation layer increases delays between a wireless sensor network and a gateway. It also adds a layer of complication to the architecture, creating one additional unreliability factor.