The manner by which home users will access Internet, download audio and video contents, placing calls over VoIP technology, control and monitor home appliances and operate many other media-centric applications in their home is undergoing tremendous changes, thanks to the emerging digital home technologies. Digital home could cater for a number of services, such as data, voice, video, communication and broadcasting as well. The scope of digital home can be defined by the following five clusters:
Digital Home Appliances
Provide High-Speed Internet access in home.
Examples: DSL, Cable Modem, Powerline and Fiber-to-the-Home (FTTH).
Act as medium for audio, video, data and Internet services distribution in home. Residential gateway connects devices via broadband infrastructure to network service provider and home network.
Various protocols such as Bluetooth,IEEE802.11 and HomeRF establishment for connection and distribution of audio, video and data between different digital home appliances and devices.
A software layer functions as interface between hardware and software system to support application and devices configures in digital home. Middleware is important for new services deployment.
Examples: OSGI, UPnP and HaVi
Consists of consumer electronics, home appliances, entertainment devices, set-top-boxes and wearable computing devices.
Figure 1: Digital Home Clusters
Viking Electronics – Free Catalog
The digital home is expected to burst at the seams with a new breed of consumer devices and multimedia contents by providing a new host of opportunities for service providers. Service providers will be able to bundle value added services such as interactive TV, video-on-demand (VoD), interactive advertising and intelligent appliances. At same time, those service providers need to leverage between the consumer requirement and technology feasibility of digital home to explore new avenues for revenue growth. The quest for digital home technologies has been around for almost two decades. At the heart of many technologies that are popping up in the digital home is Web Services technology. Web Services technology is a standardized approach of integrating various application on common platform over an Internet protocol as backbone. Web Services can perform operation from simple requests to critical tasks in a digital home especially in bringing the logical extension from hardware to software. For example, the digital home could offer a Web Service that allows a home dweller to check current status of the entertainment and home appliances as well as providing energy consumption control by turning ON or OFF the desired appliances. On the other hand, the digital home could utilize the Web Services to schedule the audio and video content playing in the media servers according to each home dweller’s preferences. These are some simple examples, whereas in reality there are vast major of potentials for Web Services to dominate the entire home scenario by providing common framework of integration. Scalability and interoperability are two key themes that could describe the total functionality of Web Services in digital home. Digital home systems are scalable with Web Services given by the loosely coupled and asynchronous characteristic of Web Services, meaning that components or services can be added or removed using them at any point of operation without affecting its functionalities and performances. The Web Services also provides total interoperability by handling the heterogeneity (differences in network, hardware and operating systems) in digital home systems. Some common examples of digital home systems are shown in Figure 2 below:
Figure 2: Digital Home Systems
Web Services Technologies
Web Services acts as â€˜protocol glue’ for various services and technologies offered in digital home. The use of Web Services in digital home serves as paradigm of convergence and assures the digital home to become a natural and native distributive architecture. Deployment of Web Services technology transforms the digital home into an Internet node by itself and provides the opportunity to use all the services available on Internet. A typical Web Services consists of three entities:
1. Service Provider : Create Web Services and publish to the external environment by registering through the Service Registry
2. Service Registry: Handle the registry of published services
3. Service Requester: Find the required services by corresponding to the Service Registry and bind their applications accordingly to the Service Provider.
Figure 3: 3 entities of Web Services
These 3 entities are essentially founded upon three major standards called Simple Object Access Protocol (SOAP), Web Services Description Language (WSDL) and Universal Description, Discovery and Integration (UDDI). The term Web Services itself describes the way of applications integration using XML, SOAP, Web Services Description Language (WSDL) and Universal Description, Discovery and Integration (UDDI). XML is used to tag the information, SOAP to transfer the information or data, WSDL used to describe the services available and UDDI is used for services listing. SOAP is a lightweight protocol for sending messages from one application to another over the Web. The SOAP protocol specifies an envelope for transmitting messages and describes how information can be packaged into an XML document. One of the advantages of SOAP is that it can invoke procedures between digital home components and services that is platform independent.
The second standard, the Web Services Description Language (WSDL), used to describe the programmatic interface of a web service. This includes data type definitions, message format, protocol bindings to home users without the need to address or understand the differences between the digital home components. An integration tools called WDSL file acts as published guideline to access valuable data sources or more like an agreement between a data producer and a data consumer. The published service tells the different digital home components on the core functionality and data offered in order for interoperation takes place among the specified components. The third standard, Universal Description, Discovery and Integration (UDDI) defines on mechanism where businesses publish electronic information about their core business and register their web services as well as to interoperate with other premises that offer such similar services. UDDI was founded by Microsoft, IBM and Ariba in September 2000 and now expanded by including more than 200 companies. UDDI focuses on centralized repository of web services information, inclusive of published location of WSDL files. Initially UDDI expected to play significant role in bringing e-commerce to greater heights on Internet but also found its way penetrating slowly into scenario of digital homes especially with many proprietary devices and systems available.
Digital Home as Data-Centric Environment
Today, there are many sub-systems operated by different vendors and service providers in digital home. Digital home increasingly becomes a data-centric environment and there is need for standardized integration methods to manage all the digital home components. One of the challenges for digital home systems, service providers and home dwellers is that there has never been cost-effective or standardized integration connection all the components and systems for optimized operational of home. Number of gateways and routers are rising increasingly; resulting in high cost and complicates the manageability aspect on the home user’s side. Another important factor worth highlighting is the existence of legacy systems in home represents significant investments of home user. Home users would prefer to complement the legacy systems with new systems in a digital home architecture. By leveraging the advantage of Web Services, home users, service providers and vendors will be able to provide access to disparate digital home systems. Web Services as standardized integration method will allow data elements and capabilities of one component to be utilized directly by another component, solving the interoperation problem between the legacy and new systems in digital home scenario. Some of the digital home application realized by Web Services is shown in Table 1 below:
Digital Home Applications
With Web Services
Layering of standards from various home network protocols
Integration and Interoperability
Interoperation of digital home components using XML and Web Services
Use of Web Services as business integration among various vendors and service providers
Extend the home databases to utility service providers in enterprise level
Secured technologies for home control, utility services, banking and e-commerce.
Web Services for signaling and event execution
Provide hybrid integration of wired and wireless infrastructures in digital home
Table 1: Web Services in Digital Home Applications
Web Services are flexible in terms of their solid and simple set of definitions using XML language. This provides digital home vendors ease to create a set of data applicable to the applications they targeted. Presently, there are two major and distinct challenges in moving Web Services towards the vision of digital home. First, deciding on how the different entities of a home can cooperate together in an integrated manner and secondly the problem of connecting digital home components and systems in real-time to the utility industries (i.e. power generation, water supply). Web Services seems to be the appropriate solution that can combine TCP/IP networking, browser-based multimedia interface and control instructions. Consider this scenario in digital home: an energy management module in digital home can be linked to the utility service provider to estimate your usage time and obtaining pricing list. This can be accomplished by Web Services providing remote real-time updates and percentage of energy consumption that alerts the home users. Therefore, home users can make smart decision in increasing energy efficiencies and independence by utilizing the Web Services technology.
The role of Web Services in digital home is guaranteeing interoperability among devices, services and systems involved. Web Services generally provide communication and coordination infrastructure to digital home systems which may have minimal computational ability for interoperation. Interoperability in digital home is achieved between components and services offered when they are capable of transparently collaborating on a particular service that they provide to the home user. Interoperability is the central cohesive source of support in digital home systems. This includes the capability for these services to communicate each other and exchange meaningful information. The digital home building blocks needed Web Services to facilitate interoperability features as described below:
1. Universal framework for control, configuration and management: Web Services could enable the functionality to identify presence of services and their capabilities in the digital home network. Web Services also provide the means to control the operation with standardized manner.
2. Visible connectivity between devices, appliances and services in digital home: Web Services will enable end-to-end connection between all appliances and services exchanging information in digital home.
3. Interoperation media services for streaming protocols: Web Services could provide common streaming protocols between various media formats and devices in digital home so that they can be shared and consumed.
4. Control and operation management: Web Services will establish a framework across all devices and services in the digital home to ensure proper exchange of control and media information between components provided by different vendors.
5. Authentication mechanism: With many devices and services in digital home, unified authentication can only be achieved through Web Services, providing compatible authorization and security to enable services request and access in digital home.
In a nutshell, Web Services can be justified as a clear opportunity for digital home to enable integration with multiple services and devices. In recent times, Web Services is seen as solution to overcome software and business integration challenges. Key players like Microsoft, IBM and industry-wide initiatives such as OBiX and CABA are working together to provide consistent way of exchanging information within digital home and across the Internet, supporting heterogeneous environment. On standardization issues, Home Electronic Systems Standards, lead by ISO/IEC SC25/WG1 published the first part of ISO/IEC 18012-1: Guidelines for product interoperability standard in homes and second part is being discussed. By implementing Web Services, all entities in digital home could â€˜speak the same language’ or work on an open and universal platform. As consumer electronics continue to pervade homes and businesses and as home users demand integration among various services and vendors, Web Services will enable digital home to work together in ways never before possible.
1. Open Building Information Xchange(OBiX), http://www.obix.org
2. Continental Automated Buildings Association(CABA), http://www.caba.org
About the Author:
Thinagaran Perumal is pursuing his PhD in Smart Technology and Robotics and attached with Institute of Advanced Technology, University Putra Malaysia. He has been involved in research areas of middleware technologies and interoperability for smart home environment. He can be reached at firstname.lastname@example.org