02-02-2013, 10:38 AM
Integration of Wireless Sensor Network Services into other Home and Industrial networks
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Abstract
Wireless sensor networks (WSN) have recently been
proposed for a large range of applications in home and industrial
automation, and for health and environment monitoring.
Especially the ZigBee standard is getting rising attention as it can
be used to implement wireless sensor networks, because of its low
data rate and low power consumption. Increasingly there is a
need to access wireless sensor network services from other IPbased
networks. The DPWS has been chosen to implement the
integration of the different forms of networking services. DPWS
uses web services, xml, WSDL and SOAP protocol to connect
various devices and services in home and industrial applications.
It allows collaboration and dynamic reconfiguration of network
services and devices. This paper will describe our idea of how
DPWS can be used to integrate a wireless sensor network into
other IP-based networks.
INTRODUCTION
Recently, different types of networks can be seen in every
place in home, car, factories and companies. Furthermore,
wireless sensor networks (WSN) are becoming more and more
important for home and industrial applications, and the need to
access these networks from other existing networks is
continuously increasing. The benefit of WSN will be largest, if
the exchange of data between WSN and other networks is
bidirectional and happens in suitable time. In general SCADA
systems are used to manage real-time data in industrial
automation, where a gateway is used to exchange data between
MODBUS/TCP and WSN and such gateways are available on
the markets. In these solutions OPC and DCOM programming
technology are used.
WIRELESS SENSOR NETWORK
Wireless sensor networks (WSN) have recently been
proposed for a large range of applications in home and
industrial automation. It consists of many tiny nodes, which
have several sensors and a radio interface that depends on the
IEEE 802.15.4 standard that supports large number of
embedded devices in one network. WSN can be used for many
applications such as environment monitoring, medical
applications, robotic systems and home and industrial
automation. WSN uses ZigBee standard (IEEE 802.15.4),
which is a standard for low-rate wireless personal area
networks (LoWPAN).
SERVICE-ORIENTED ARCHITECTURE SOA
A service-oriented architecture (SOA) is a distributed
software architecture that depends on web services for building
systems. In this architecture the client looks up for the services
that are normally registered in the services directory, and the
data is usually exchanged in XML format. The web services
architecture is based on several protocols (SOAP, WSDL and
UDDI). The communication between the web services and the
client is based on the SOAP protocol and uses XML as data
format as shown in the Fig. 1.
IPV6 /6LOWPAN MAPPING
There is a need to access the wireless sensor networks from
other IP-based networks. In order to achieve this need the
TCP/IP packets should be transferred through the ZigBee
packets, but there is a difference between the OSI model of
TCP/IP and the OSI model of ZigBee, this resulting into a need
for a new layer that makes the adaptation between the two
standards as shown in Fig. 3
DPWS GATEWAY SOLUTION
Our solution of DPWS gateway comprises a model of web
services that uses XML, WSDL and SOAP and enables the
exchange of data between WSN and other IP-based networks.
Fig. 4 shows the overall concept of a DPWS gateway,
which allows applications to read data from the WSN sensors
and to issue commands to the WSN devices. It is running on a
PC under Windows or Linux. The PC running a DPWS
gateway has access to an IP network and it connects to at least
one coordinating device in WSN which acts as a bridge
between other WSN devices and the PC.
CONCLUSION
The presented paper has discussed the need and how to
integrate wireless sensor networks into other existing IP-based
networks.
Using the 6LoWPAN it is possible to connect a wireless
sensor network with the internet and other IP-based networks
in home and industrial environments. The 6LoWPAN also
implements the header compression and fragmentation as well
as reassembly of fragments in order to map from IPv6 to
ZigBee network.
The DPWS Profile was chosen to achieve the
implementation of a DPWS gateway because it is suitable for
embedded devices in home and industrial automation, and
because of its interoperability and its automatic networking and
discovery of services.