Seek a relatively complete smart home scheme

As an ancient saying goes, "Fiona Fang cannot be made without rules", so it is in the field of smart home. Technically, the challenge of smart home construction is not equipment or implementation, but standards and protocols. Smart home is a multi-industry system engineering, and equipment manufacturers produce equipment according to different interface standards and protocols. Therefore, the interconnection and communication between different devices is very difficult. Therefore, establishing standards and protocols to be followed is the first problem to be solved in the development of smart home. At present, the international standards in the field of smart home are not yet mature, and major manufacturers and related organizations are working hard to establish and formulate network interface standards and data transmission protocols between devices in smart home systems. Seizing the opportunity and participating in the formulation of standards will bring endless opportunities to domestic manufacturers.

Home bus system

Home bus is an important foundation to realize smart home, and it is the nervous system in the house. Its main function is to connect all kinds of electronic and electrical equipment in the home, and is responsible for connecting all kinds of communication equipment (including security, telephone, home appliances, audio-visual equipment, etc.). ) form a complete home network at home.

Japan is one of the countries that promoted the development of smart home earlier. The concept of home bus system (HBS for short) was put forward earlier, and the research institute of home bus (HBS) was established. Under the guidance of the Ministry of Posts and Telecommunications and the Ministry of International Trade and Industry, the HBS standard committee was established, and the HBS standard in Japan was formulated. According to this standard, HBS system consists of a coaxial cable and four twisted pairs, the former is used to transmit image information, and the latter is used to transmit voice, data and control signals. All kinds of household appliances and electrical appliances are connected to HBS in some way. These electrical equipment can be controlled indoors or remotely controlled by telephone in different places. At the beginning of 1988, in order to meet the needs of large residential communities, Japan Housing Informatization Promotion Association introduced the Super Home Bus System (S-HBS for short), which has a wider scope of application, because one S-HBS system can connect thousands of home intranets.

Home intelligence requires many home appliances and networks to be compatible with each other, and bus protocol is its essence. Only when the interface is smooth can household appliances "understand" the instructions issued by people, so the physical interface form of bus standard is one of the important problems to be solved urgently in smart home. At present, the bus standard protocols are mainly proposed by American companies, including LonWorks protocol of Echelon company, CEBuS protocol of Electronic Industry Association (EIA), Smart House protocol of Smart House LP, X- 10 protocol of X- 10 company, etc.

These agreements have their own advantages and disadvantages. LonWorks protocol is a field bus technology developed by Echelon company in the United States and advocated by Motorola and Toshiba company. It supports a variety of physical media, suitable for twisted pair, power line, optical cable, radio frequency, infrared and so on. , and can be mixed in the same network. LonWorks protocol supports a variety of topologies, you can choose any network topology, and the networking mode is flexible. The application scope of LonWorks mainly includes building automation, industrial control and so on, and it has good performance in constructing distributed monitoring network. At present, there are more than 500,000 LonWorks nodes in the world. Among these four protocols, X- 10 is the oldest and simplest one to use. 1978 was born in America, and it is still the leading home automation system in America. The reason why X- 10 protocol is simple is that it directly uses the residential power line as the control bus, and connects each controller with each functional interface through the power line to realize program control, which is more conducive to changing the structural space, users can install it themselves, and the price is relatively low. CEBuS, as an electronic industry promotion agreement, together with EHS standards in Europe, is the recommended industry standard for home automation electronic products in Europe and America.

Internal transmission interface

The internal transmission interface of smart home system can be realized by two transmission modes: one is wireless transmission; The second is the wired transmission mode. At present, the popular physical layer interfaces in the world mainly include radio frequency (RF), power carrier (PL) and twisted pair (RS485). ), dedicated lines IEEE 1394, IEEE 1394b, HAVI using IEEE 1394, Bluetooth technology, wireless communication Ethernet (IEEE 802.1/), X1/. These interfaces include low-speed data link interfaces represented by intelligent device monitoring and high-speed data link interfaces represented by home multimedia entertainment and video monitoring.

Wireless transmission mode is most suitable for home use. At present, the wireless transmission technologies used in the family mainly include wireless communication household radio frequency, Bluetooth technology, WAP, wireless Ethernet and so on. And people are more optimistic about HomeRF and Bluetooth technology. HomeRF is mainly designed for home network, which is the product of the combination of IEEE 802. 1 1 and DECT. 199965438+1On October 5th, HomeRF Working Group published the version specification of SWAP 1.0, and 13 companies (including IBM and Intel) promised to produce products based on SWAP.

Bluetooth (IEEE 802. 15) is the latest standard, which is more mobile than wireless Ethernet (IEEE 802. 1 1). It can connect devices to LAN and WAN, and even support global roaming. In addition, Bluetooth has low cost and small size, and can be used in more devices.

Other technologies are more or less problematic. For example, the prospect of IEEE 802. 1 1 technology in the home market is not very good; Radio frequency (RF) technology has high maturity, low cost and good penetration, but the disadvantage is that there is no unified standard, and the communication protocols of different companies are different. Infrared technology is very mature, flexible and low cost, but limited by obstacles, it has no penetration, poor directivity and no standard communication protocol. At present, radio frequency has become one of the most realistic and popular physical layer interfaces because of its reliable data transmission performance and low cost without additional wiring resources. It can be predicted that with the gradual maturity of wireless mode, it will replace wired communication and become the best connection mode of home network in the future. However, at present, home wiring is mainly wired, mainly including the following three types:

The first is home network wiring. This is the most widely used technology at present, but it is also the most troublesome technology. The urgent problem to be solved in this way is the convenience of wiring and how to realize plug and play.

The second is to use the telephone line at home for network connection, and the technology adopted is Home PNA (Home Telephone Line Networking Alliance). HomePNA aims to introduce simple and low-cost home users as soon as possible to solve the problem of home internet access without network connection. Its disadvantage is low network speed. Internet access is supported, and the supported interface protocols are V.90, ADSL and Cable Modem. At present, the scheme of HomePNA is still being worked out, and the limitation of bandwidth is an unfavorable factor restricting the development of this technology, but it is still very attractive because of its simple and practical network medium.

The third way is to use the existing power line at home to transmit data and use the power line carrier technology. The system transmits information through the 120V/60Hz power distribution system in the home or equipment. At present, the communication protocol adopted in this way is mainly X- 10. The advantage of adopting power line networking scheme is that it does not need to rewire at home and can use the existing power socket, so it is also one of the research and development directions of home network.

Especially worth mentioning is IEEE 1394, which is a high-speed universal serial digital interface standard for connecting computers and peripheral devices, and it focuses on the application of cable connection. This standard defines the medium topology and transmission protocol, and is a software and hardware integration standard. IEEE 1394 is likely to become the universal interface standard for the future network, and it will be the latest interface standard for the next generation of computer peripherals and consumer electronic products, and it is still under further development. With the wide use of digital equipment, various high-definition multimedia, digital AV systems, and multimedia data exchange between digital set-top boxes and computers all adopt IEEE 1394 interface standard, which makes this standard a * * * interface between consumer electronic products and computers, and can realize automatic control of TV, movies, video recorders, audio systems, etc., and can be connected with external ATM networks to realize information expressway between home and the outside world.

External internet mode

The connection between home internal network and external internet can also be divided into wired and wireless ways, but at present, wired ways are mainly used, including Ethernet private line, cable modem, telephone line XDSL and so on. Among them, the access cost of Ethernet private line is relatively high, which is suitable for new residential areas; The cable modem uses the existing cable TV network with low cost, which is very suitable for the transformation of the existing community. XDSL, similar to Cable Modem, is also mainly suitable for the renovation of old residential areas.

At present, there are a variety of devices that can directly access the high-speed Internet through broadband: the first is to access through a PC, which is the most traditional way; The second is the set-top box. In a sense, this is not a simple set-top box, but a set-top box computer, which acts as the entertainment center and information center of the whole family. The third type is Bluetooth gateway, that is, access point, which connects information appliances supporting Bluetooth protocol with home network and accesses high-speed Internet. The fourth is Home Controller (IHC), also known as Home Information Platform (HIP). It is not only the control center of the family, but also the entertainment and information center of the family. At the same time, it acts as a gateway between the home control network and the Internet. With it, people can freely control all kinds of electrical equipment at home through the Internet.

Related schemes and standards of HIP

People's basic requirements for family information platform are multifunction, easy to use, safe and reliable, and low price. Some big manufacturers have put forward relevant standards and schemes about HIP, and the mainstream ones are:

1.HAVI system

Havi (home audio/video interoperability) is the interconnection and control standard of audio/video electronic products in home network. Based on the underlying protocol of IEEE 1394, it mainly realizes the transmission of digital audio and video content between Havi devices and the operation of these contents.

2. Jini Technology

1999 65438+ 10, Sun Company released Jini technology, which provides such a mechanism that a group of devices can be safely attached to a service network by using Java language, so that devices can establish contact anytime and anywhere.

3.OSGi open service gateway

The main purpose of OSGi (Open Service Gateway Initiative) is to define an open standard for connecting commercial services on the Internet with the next generation of smart home appliances, which may become the service standard of the intelligent information home appliance platform. OSGi is compatible with various LAN technologies, including various wireless and wired data and audio/video local transmission standards, such as Bluetooth, HAVI, HomePNA, HomeRF, IEEE 1394, power line communication system, USB, etc. Another feature of OSGi is that it can coexist with other standards. In the physical layer, OSGi is compatible with Bluetooth, HAVI, HomePNA, HomeRF, USB and other standards. In terms of device access architecture, OSGi is compatible with logical device access technologies, such as Jini and UPnP. In addition, OSGi also supports a variety of connection modes with WAN, such as Modem, DSL, Cable Modem, etc.

There are many technologies related to smart home standards, interfaces and protocols. At present, it is impossible to simply determine which technologies or technologies are standards, and it is impossible to accurately predict which technologies will become the final standards in the future. However, when the market enters a mature stage, those products that have an advantage in the market will definitely affect the formulation of standards. In addition, due to the diversification and individualization of human life, the design of smart home in the future will be tailored to local conditions, rooms and homes, and its standardization should also be highly open. Therefore, the related standards, interfaces and protocols of smart home in the future must consider the linkage control function of each system and the compatibility of the old and new systems, and design the system into an efficient and open system, so that every family member can use it conveniently and easily, leaving room for future product improvement and function upgrade.