Design Considerations

In following paragraphs we will address some design considerations before we propose new system – eHome system. Furthermore, we will offer some possible solutions to solve the integrating problems.

4.3.1 Multiple Home Systems and Interfaces

According to our observation, multiple different home systems will coexistence in the future home. Besides, there will be more and more network interfaces, such as BluTooth, Ethernet, IEEE 1394, HomeRF and Wireless LAN in the future home.

Furthermore, digital appliances, such as PCs, PDAs, digital AV devices, and other various IAs will coexist and be connected by multiple different network interfaces and home systems in future home design. Finally, all of them will be able to share the

service with each other in the future.

However, two main problems may be raised. The first one is the interoperability of the services between different home systems. For example, it is difficult that HAVi-based service want to access the services provided by UPnP. The second one is interoperability between different home networking interfaces standards. For example, on basis of their standards, there is no method to transfer a data packet from IEEE 1394 to HomePNA.

In order to solve these problems addressed above, we propose a gateway-based architecture. Figure 4.1 is the illustration of gateway-based architecture. You can see that eHome system uses eHome Residential Gateway and eHome Room Centers to integrate existing home systems and network interfaces. Each of them is responsible for interoperability of services that are used by different home systems and network interfaces with each other, and some special functions. More details will be discussed in the remaining paragraphs.

4.3.2 Web services

Web services are widely used in Internet, especially HTTP. Furthermore, more and more appliances including PCs, the portable devices and the public devices (such as KIOSK), are built in the web browser. Therefore, we believe, HTTP is the best choice for our eHome system to provide the capability of remotely accessing services of the home appliances wherever the users are either inside or outside home.

The emerging technology, WAP, is the famous web service solution for potable device. It is more appropriate than HTTP for devices with limited resources. In other words, end user can access the resources of Internet though WAP with portable devices. Accordingly, we believe that HTTP protocol and WAP are the best approach to provide capability of remotely accessing services provide by home appliances outside or inside home.

4.3.3 Portable devices

More and more people carry the portable device with them or put it nearby, even at home. This shows that the demand and applications of the portable devices are significantly growing in recent years. For this reason, we believe it is very important

to integrate the portable devices into the future home system.

Moreover, there are no existed home systems integrating with the portable devices to support the capability of the remote access. Furthermore, we think that the portable devices will be very famous and important appliances in home networking application in the future. It could be a convenient device to remotely access all services of whole home systems. Besides, it can provide access services remotely inside home, but also outside home when the home appliances are either indirectly or directly connected to Internet. Hence, we propose to integrate the portable devices into eHome system. It plays a core and important role in eHome system.

4.3.4 eHome System Protocol

The home applicant services may be multimedia streaming, voice service, or the control commands only. Therefore, like VSG-based framework, we propose that what kind of the protocols should be chosen as an eHome protocol is depend on demand.

Besides, choosing what protocol as an eHome protocol will influence many design considerations. For example, choosing HTTP as our protocol, we need to construct TCP/IP network as our infrastructure and use the URL as our naming approach.

4.3.5 High Flexibility, Scalability and Low Cost

It is very difficult to construct the whole home system by the existing home system standards because no home system meets all the requirements. However, according to the trend of home networking, there will be many home system standards coexistence in the future home. In other words, to construct the home system using the only one standard is unrealistic and inflexible. However, it is an urgent demand to design a home system, which can integrate with all home systems and interfaces.

For this reasons, we propose a general home system which is more flexible than current other home systems. We hope the system with the feature of scalability. That means that eHome system we proposed could be implemented with lowest cost but still keep the original features. Of course, it could also be implemented with higher cost and more functions. For example, you can construct an eHome system with lowest cost and the capability of the controlling home appliances, but this implemented eHome system cannot support the multimedia services. Besides, if you want to support the multimedia services, you should spend more cost to meet this

requirement. Because of the required features described above, we do not specify the implementing approaches and what kind of technologies should be used in this report.

Consequently, eHome system become more flexible and scalable, but it also leaves many issues and unsolved problems for the future research.

We utilize the recent technologies to implement a tentative prototyping of eHome system with lowest cost. According to such prototyping, we can evaluate the practicability and observe the possible improvement in the future. The details about implementation are introduced in Chapter 5.