Encoding and Compression for the Devices Profile for Web Services

Most solutions for Wireless Sensor Networks (WSN) come equipped with their own architectural concepts which raise the problem of possible incompatibility of computer networks and the WSN. Often gateway concepts are used to overcome this problem. But this is not the best solution on the long term. Other research fields and industrial domains are heading for universal cross domain architecture concepts based on internet technologies that are more mature and better understood. The IETF 6LoWPAN working group provides the groundings for standardized communication using existing network protocols like IPv6 also in low power radio networks. A big challenge when deploying further application layer network protocols on top of 6LoWPAN is the message size of existing mostly XML based protocols which does not meet the resource requirements of deeply embedded devices without further research efforts. This paper presents different data compression techniques for the Devices Profile of Web Services (DPWS) to be applied in 6LoWPAN networks. Therefore, we analyze a realistic scenario. We determined 18 message types in the scenario and compressed and encoded all messages by using existing schemes and tools. For the first time, we also investigate on the Efficient XML Interchange (EXI) format for DPWS.