At present, we cooperate with major companies at home and abroad, such as Intel, Haier, Samsung, LG and Panasonic. Has announced its entry into the digital home market. With the rapid development of digital technology and network technology, digital home has entered the stage of intelligent digital home after experiencing the stage of wireless city and network appliances. With the gradual maturity of related technologies and the emergence of products with substantial applications, digital home is now at a turning point from concept to practice, and an upstream and downstream industrial chain connecting communication service providers, content and value-added service providers and terminal product manufacturers is gradually taking shape.
The concept of digital home is to connect all kinds of consumer electronic products into an interconnected home network on the basis of digitalization and networking of household appliances, so as to realize mutual identification, control and information sharing of computers, communication equipment, entertainment products, household appliances, optical sensors and other electronic devices.
At present, although the application scope and emphasis of products of different companies are different, the basic application function framework of digital home has gradually become clear and perfect, mainly including:
Security: Intelligent security monitors the occurrence of illegal entry, fire, gas leakage and emergency call for help in real time. Once an alarm is given, the system will automatically send an alarm message to the service center or the owner, and at the same time start the relevant electrical appliances to enter the emergency linkage state to realize active prevention.
Intelligent control of consumer electronic products: microwave oven that can automatically control heating time and temperature, intelligent air conditioner that can automatically adjust temperature and humidity, TV/video recorder that can automatically search TV programs and realize remote video recording according to instructions, etc.
Interactive intelligent control: realize the active action response of intelligent information home appliances through various sensors (such as temperature, sound, action, etc.). ), and users can also define various scenarios for information appliances to respond. For example, you can set a smart home controller: "Turn on the back door light at 5 pm and adjust the air conditioner to 25 degrees."
Home information service: Smart home server can provide the latest stock market information, news, weather forecast, TV program forecast, and even the current traffic flow on the expressway, and can also automatically manage users' financial information such as utilities, bank and credit card accounts.
Entertainment information * * * enjoyment: realize the enjoyment of audio-visual information within the family * * *. No matter what device and format the information is stored in, it can be played on different playback devices.
Automatic maintenance: Intelligent information appliances can download updated drivers and diagnostic programs directly from the vendor's service website through the network to realize intelligent fault self-diagnosis and automatic upgrade of new functions.
2 digital family composition
The devices in digital home can be divided into low-speed control devices, high-speed information devices and network communication devices.
Low-speed control equipment: the control electrical equipment in the home includes various sensors, white goods systems, lighting curtain systems, etc. This kind of equipment requires low communication speed, stability and reliability, and low bit error rate, and mainly realizes the control and management functions of the equipment. Generally, the processing power of this kind of equipment is not very strong, and most of them are very sensitive to price, so it is required to increase the home network function without increasing too much cost.
High-speed media information equipment: this kind of equipment mainly includes media center, TV, stereo, set-top box, video recorder, camera, DVD, PDA and office equipment such as computers, printers and projectors. Capable of data and multimedia processing. This kind of equipment needs to transmit a lot of data, especially multimedia information such as audio and video, so it requires high communication speed and low transmission delay.
Network communication equipment: this kind of equipment is the communication terminal equipment in the family, such as fixed telephone, mobile phone, etc. This kind of equipment can communicate directly with the outside world through the communication network, but it lacks the function of directly connecting with the internal equipment of the home network through the local communication interface.
In the home network, the mutual recognition and interconnection between devices is the basis of various applications of digital home. How to make all kinds of devices in the home interconnected will be a very important topic.
Interconnection can be divided into the following levels: the establishment of basic communication between devices in the home network (high-speed devices and low-speed devices communicate through high-speed and low-speed networks respectively), the mutual communication between devices in high-speed and low-speed networks, the unification of various device functions and data descriptions, and the unification of terminal device interfaces.
3. Establish basic communication system
As we have already introduced, the home network consists of low-speed and high-speed networks. The interconnection of home network devices must first solve the problem of establishing low-speed and high-speed networks. High-speed devices are interconnected through high-speed networks, while low-speed devices are interconnected through low-speed networks, which requires the support of a unified home network communication protocol.
The family network standard series, which was compiled by the family network standard working group organized by the Ministry of Information Industry and participated by many household appliances, IT, communication and chip enterprises, was released by the Ministry of Information Industry as an industry standard in June 2005. Among them, the communication protocols of high-speed and low-speed networks have clear provisions:
Through this communication protocol, the interconnection problem between high-speed equipment and low-speed equipment supporting this protocol is solved.
4 high-speed and low-speed network interworking
Digital home includes all kinds of electrical equipment, including high-speed and low-speed network equipment. Although the requirements of high-speed network and low-speed network are different, there should be a unified network information management platform in the whole home network to unify the high-speed and low-speed networks at the application level and realize interconnection.
The unified device network communication management platform is used to connect high-speed and low-speed networks in the home, transfer the communication between devices in the home, and manage the devices in the home network in a unified way. This platform is the home gateway.
Home gateway has high-speed and low-speed network communication interfaces, supports high-speed and low-speed network communication protocols, can directly communicate with high-speed and low-speed network devices, and can convert the communication between low-speed and high-speed network devices into target addresses and information formats, thus achieving the purpose of transmitting low-speed and high-speed devices and realizing the interconnection of the two types of devices. The home network standard published by the Ministry of Information Industry also stipulates the interconnection mode of low-speed and high-speed equipment.
5 equipment description file
There are many kinds of network devices in the home network, which require certain compatibility and expansibility. Compatibility lies in that devices from different manufacturers can be compatible in the home network, and its expansibility lies in that various new electrical devices can be added to the home network. The device file method can be used to describe home network devices. Many protocols use the method of device description file to solve the universality problem of communication and management software of different devices.
Some equipment description methods adopt unified classification and definition according to the variable parameters of terminal equipment, which involves unifying the functions and control commands of each type of equipment. This method needs long-term discussion and communication from various equipment manufacturers, and needs to be constantly revised according to the increase of equipment functions. This has certain restrictions on the differentiated function design of terminal equipment manufacturers, especially the common practice in the industry that hopes to gain the favor of the market and users through differentiated functions.
We can also adopt a more open and flexible device description method, that is, only specify device functions and their parameters, control commands and user interface description methods, without specifying specific functions and parameters, thus bringing greater flexibility and development space for terminal equipment manufacturers. Each home network device has a device description file describing its own functions and commands. The device description file contains not only the manufacturer information of the device, but also the operation description of the device, the command corresponding to each operation, the status code of the device and other information. Through the device description file, we can know what function the device has, send a command to realize a certain function, and get the current status of the device from the status code and display it graphically.
The complete working principle of the device description file is shown in the following figure:
Device registry: stored in the main control device of the home network, storing device information describing the devices registered in the home network. After the device applies for registration, it is necessary to add the information of the new network access device in the home network device registry; After the devices in the network are logged off, the corresponding items in the device registry should be deleted.
Device description file: each device has a corresponding device description file, which contains structured data describing the device, corresponding icons, text, voice and other information resource index information.
Command generation unit: compare the command generated by the visual page display unit with the related device description file, generate the corresponding communication command, hand over the information to the application layer for processing or process the data string from the application layer, and send it to the visual page display unit according to the related data structure of the device file.
Visual interface display unit: for the equipment with control interface, it is necessary to generate the control interface of the controlled equipment according to the equipment description file, and the visual interface display unit generates the control interface according to the appearance description in the equipment description file to extract the operation information on the control interface.
Icon, text and voice resource library: the equipment file contains the index of external icons, graphics, text and voice, and the corresponding icon, text, voice and other related resources are stored in the corresponding resource library according to actual needs.
The description of equipment can be divided into the description of external manifestations and the description of its own functional data, in which the description file of external manifestations is used for the main control equipment with display interface to generate the display interface, and its own functional data is used for the functional analysis of equipment transmission data. In order to unify the interface and data better, the data is described by components and instructions. A complete device description includes: the description information of the device itself, the description of the components that make up the device, the description of related connection resources, and the logical relationship of the device itself, among which the most important thing is the description of the components that make up the device. Components are divided into single input components, single output components and input-output components according to input-output forms; According to its external manifestations, it can be divided into switch type, enumeration type, scroll bar type and single instruction type.
The equipment is described as follows:
The device description file can be stored in the device's memory or gateway, or even downloaded from the service support website of an external manufacturer. When users need to add new equipment, they can find the corresponding equipment description file according to the uniformly specified equipment ID number only by adding equipment on the gateway or mobile control terminal, and store the equipment description file of each type of equipment in the main control device through network download. The main control device displays what functions a certain equipment has according to the equipment description file, and analyzes the required control command values and status return values, thus realizing the centralized control and inquiry functions of the equipment and forming a good man-machine interaction. If the main control device has no display interface, the device only needs to save the functional data of the controlled device, so that different devices can be identified and correlated with each other, and the machine can identify the machine.
6 the unification of terminal equipment interface
The core of home network application is the popularization and use of home devices with network function. The establishment of the basic communication system, the interconnection of high-speed and low-speed network devices and the unified device description method have solved the interconnection problem of various devices from different manufacturers, and solved the interconnection problem of devices in the home network from the technical level. From the actual product development and production level, it is still necessary to solve the problem of how to quickly upgrade ordinary household equipment to equipment with home network function.
For a large household equipment manufacturer, there are many kinds of self-owned products, and new products need to be continuously introduced due to market competition. If we solve the interconnection problem of adding network functions specifically for each product in the development process, we need to invest considerable energy; The end user of each new product may have a variety of network connection interface options, and the number and scale of a single product will increase the development and production costs of the product.
In order to solve the practical problems and needs in the process of home network industrialization, it is necessary to separate the general functions of home network equipment from the network functions, and it is the most direct and effective solution to determine the unified interface between home equipment and network communication module.
Unified terminal equipment interface includes hardware and software. The hardware part specifies the hardware interface between the device and the network communication module, including data, power supply and necessary control signals; The software part specifies the data interaction between the device and the network communication module, such as data transmission, data reception, control of the device itself, state feedback and data processing. Once the home network interface of the terminal equipment is determined, the terminal equipment manufacturer can be liberated from the work of developing network functions and interfaces for each product, and the enterprise specializing in the development and production of home network communication modules can produce unified modules, in which as long as different device description files are provided for different devices to be connected, they can cooperate with the corresponding network communication modules to form a home network equipment together. In this way, the development and production cost is modularized, and the cost is greatly reduced, which is very conducive to the popularization of home networks.
It should be said that the device description file solves the interconnection problem of home network devices from the technical and logical level, while the unified interface of home network devices solves the interconnection problem from the product and promotion level, so these technologies are very critical.
7 outlook
This paper mainly discusses the device interconnection under the same home network technical standard system, which requires all terminal equipment manufacturers to follow the same communication protocol, device description method and device interface specification. Of course, this is also the embodiment of the dependence on technical standards in the current home network development.
However, at present, the home network is still in the early stage of development, and various new concepts, technologies and products are constantly emerging. Various manufacturers and different manufacturers form a number of technical organizations and industrial alliances. Different organizations and alliances have different considerations on the application of home networks, the technologies adopted and the product costs, so there are many technical standard systems on the market at present. The coexistence of various technologies is also the characteristic of home network at present, which is consistent with the initial development of a new industry.
How to realize the interconnection of home network products with different technical standard systems in the same family is the demand of actual marketing, and also the demand of realizing the continuous integration of various technical systems and finally forming the home network technical system. The research on the interconnection of heterogeneous home network technical standard equipment is also gradually carried out, and this technical research will be the focus of home network research.
8 concluding remarks
Interconnection is a very important content in home network, involving technology, industry promotion and customized application. This paper makes some preliminary analysis, but there is still a lot of work to be done in real implementation and operation. We believe that with the acceleration of the practical and productive process of digital home research, it will surely enter thousands of households.