27-06-2012, 04:23 PM
Integrating Wireless Sensor Networks with the Web
[attachment=25806]
ABSTRACT
IPv6 over Low power Wireless Personal Area Networks
(6LoWPAN) has accelerated the integration of Wireless Sensor
Networks (WSNs) and smart objects with the Internet. At the
same time, the Constrained Application Protocol (CoAP) has
made it possible to provide resource constrained devices with
RESTful web service functionalities and consequently to integrate
WSNs and smart objects with the Web. The use of Web services
on top of IP based WSNs facilitates the software reusability and
reduces the complexity of the application development. This work
focuses on RESTful WSNs.
INTRODUCTION
Recent advances in Wireless Sensor Network (WSN) technology
and the use of the Internet Protocol (IP) in resource constrained
devices has radically changed the Internet landscape. Trillions of
smart objects will be connected to the Internet to form the so
called Internet of Things (IoT). The IoT will connect physical
(analogic) environments to the (digital) Internet, unleashing
exciting possibilities and challenges for a variety of application
domains, such as smart metering, e-health logistics, building and
home automation [7].
Constrained Application Protocol
In March 2010, the IETF CoRE Working Group has started the
standardization activity on CoAP. CoAP is a web transfer
protocol optimized for resource constrained networks typical of
IoT and M2M applications. CoAP is based on a REST
architecture in which resources are server-controlled abstractions
made available by an application process and identified by
Universal Resource Identifiers (URIs). The resources can be
manipulated by means of the same methods as the ones used by
HTTP: GET, PUT, POST and DELETE.
CoAP power consumption evaluation
The use of UDP as transport protocol and the reduction of the
packet header size significantly improve the power consumption
and battery lifetime in WSNs. In order to evaluate the
performance improvement of CoAP compared to HTTP, we
executed a simple experiment. We generated a series of web
service requests first between a CoAP client/server system and
then between an HTTP client/server system.
Integration of a CoAP based WSN with
a Web application
The use of an IP based communication and a REST based Web
architecture in LLNs facilitates the integration of WSNs with
Internet based Web applications. This Section describes the
design and development of an end-to-end IP based architecture
integrating a CoAP over 6LowPAN Contiki based WSN with an
HTTP over IP based application. The aim of the application is to
allow a user to access WSN data directly from a Web browser, as
illustrated in Figure 2.
Conclusions
This paper discussed the integration of WSNs with the Web. This
is being facilitated by the development of CoAP, an IETF
protocol providing LLNs with a RESTful architecture. CoAP
offers the same methods for the resource manipulation as HTTP.
In addition, CoAP supports additional functionalities typical of
IoT and M2M applications, such as multicast, asynchronous
communication and subscriptions. Unlike HTTP, CoAP is built
on top of UDP and has a compact packet overhead. The paper
illustrated how the introduction of UDP and the packet overhead
compression drastically reduce the mote’s power consumption
and consequently increase the battery lifetime. The paper also
described the design and development of an end-to-end IP based
architecture integrating a CoAP over 6LowPAN Contiki based
WSN with an HTTP over IP based application.
[attachment=25806]
ABSTRACT
IPv6 over Low power Wireless Personal Area Networks
(6LoWPAN) has accelerated the integration of Wireless Sensor
Networks (WSNs) and smart objects with the Internet. At the
same time, the Constrained Application Protocol (CoAP) has
made it possible to provide resource constrained devices with
RESTful web service functionalities and consequently to integrate
WSNs and smart objects with the Web. The use of Web services
on top of IP based WSNs facilitates the software reusability and
reduces the complexity of the application development. This work
focuses on RESTful WSNs.
INTRODUCTION
Recent advances in Wireless Sensor Network (WSN) technology
and the use of the Internet Protocol (IP) in resource constrained
devices has radically changed the Internet landscape. Trillions of
smart objects will be connected to the Internet to form the so
called Internet of Things (IoT). The IoT will connect physical
(analogic) environments to the (digital) Internet, unleashing
exciting possibilities and challenges for a variety of application
domains, such as smart metering, e-health logistics, building and
home automation [7].
Constrained Application Protocol
In March 2010, the IETF CoRE Working Group has started the
standardization activity on CoAP. CoAP is a web transfer
protocol optimized for resource constrained networks typical of
IoT and M2M applications. CoAP is based on a REST
architecture in which resources are server-controlled abstractions
made available by an application process and identified by
Universal Resource Identifiers (URIs). The resources can be
manipulated by means of the same methods as the ones used by
HTTP: GET, PUT, POST and DELETE.
CoAP power consumption evaluation
The use of UDP as transport protocol and the reduction of the
packet header size significantly improve the power consumption
and battery lifetime in WSNs. In order to evaluate the
performance improvement of CoAP compared to HTTP, we
executed a simple experiment. We generated a series of web
service requests first between a CoAP client/server system and
then between an HTTP client/server system.
Integration of a CoAP based WSN with
a Web application
The use of an IP based communication and a REST based Web
architecture in LLNs facilitates the integration of WSNs with
Internet based Web applications. This Section describes the
design and development of an end-to-end IP based architecture
integrating a CoAP over 6LowPAN Contiki based WSN with an
HTTP over IP based application. The aim of the application is to
allow a user to access WSN data directly from a Web browser, as
illustrated in Figure 2.
Conclusions
This paper discussed the integration of WSNs with the Web. This
is being facilitated by the development of CoAP, an IETF
protocol providing LLNs with a RESTful architecture. CoAP
offers the same methods for the resource manipulation as HTTP.
In addition, CoAP supports additional functionalities typical of
IoT and M2M applications, such as multicast, asynchronous
communication and subscriptions. Unlike HTTP, CoAP is built
on top of UDP and has a compact packet overhead. The paper
illustrated how the introduction of UDP and the packet overhead
compression drastically reduce the mote’s power consumption
and consequently increase the battery lifetime. The paper also
described the design and development of an end-to-end IP based
architecture integrating a CoAP over 6LowPAN Contiki based
WSN with an HTTP over IP based application.