【 Weak current College 】 CEBUS in intelligent housing community in application mode of analysis

With computer technology and the rapid development of communications technology, particularly in recent years the rapid development of Internet, the requirements of the home is not just the space and the environment is exquisite, but on life safety, comfort, communications, information services and family intellectualization set higher requirements for intelligent building and intelligent housing community is the inevitable outcome of the information age, is the use of computer technology, communications technology and automation technology to the residential buildings of electromechanical control systems, manage service systems, communication networks, premises distribution system (PDS) and home automation system to unify, to people a safe and comfortable living, learning and working environment space. specifically, intelligent services to people in family life, it ought to have high-speed access function network, namely Internet network high-speed channel; Home Office meets the needs of Home Office; home automation for electric appliance equipment linkage control and offsite remote control, etc; home entertainment including V0D automatic on-demand, remote learning, interactive video games, etc.; home security monitoring such as fire, gas leak, child care and the elderly for help, telemedicine and monitoring, burglar alarm, etc.; household management aspects, such as the remote transmission of four tables: home business charges, such as online shopping, online business links, etc.

1 intelligent housing community communications network constitutes a mode

The intelligent housing community, its communications network infrastructure and its realization is the intelligent housing community building, an important part of it you can set a user's intelligent control system, VOD system and Internet service organic links; the community public service system linked to the community and the outside world; to the right of access to linked.

Intelligent housing community communications network consists of residential external trunk network and a network of local families-backbone network selects what network technology on the success of the network construction plays a decisive role in selecting suitable for intelligent building-network demand characteristics of mainstream network technology, not only can guarantee the high-performance network, guaranteeing the network's advancement and extensibility (including device ports, network infrastructure and network protocol extensions); as your business grows and application level, the network of data and information flow will continue to grow, the need for a network with the transition to new technologies, and as technology evolves constantly upgraded performance, to protect the interests of long-term investment; network system also should have good security, since smart communities network connectivity garden inside all users, the importance of safety management; Internet users within the community, manage their communications, do not only guarantee the quality of user traffic, and the rational use of network resources, but also built a smart communities network-facing important links. local network (HomeLocalAreaNetw) This enables families to various independent device integrated on a single home network, will conduct their own all-electric smart control, support for multiple PCs. households can remotely monitor, control, home of a variety of devices, such as advance open air conditioning, switches, lights, fax, and a series of Internal Affairs; on the water meter, electricity meters, gas meters and heat meters data acquisition and transmission over the network to the center of the data collected information, read through the Central Administration of computer data on household four tables for automatic meter reading this not only avoids, household workers meter reading and manual meter reading caused by errors, as well as property management system sector to reduce personnel expenses, improve management efficiency.

According to the intelligent housing community in varying degrees, network architecture and cabling system should vary. generally speaking, the intelligent community of the network structure is divided into three levels, the Internet access network, intelligent housing community residence outside the LAN and the family, local network, put forward several solutions.

1.1 Internet access network

The construction of the access network in China began in the mid-1990s, so far, the Internet access network to run most of the narrowband access systems-in recent years, the Internet at an alarming rate rapid development, with the increase of its services, the user's data transfer rate of demand is also growing. based on the support of traditional 64kb/s circuit switching business of narrowband access system, to IP mainstream support for high-speed data service conditions, being able to meet the market demand, so in recent years it has made a number of transitional broadband access network technologies, including ISDN, XDSL, CableModem, due to market demand-driven, this years broadband access technologies have been developed, 1999 began large-scale broadband access network testing-broadband access system is a group transfer approach, with statistical multiplexing functionality. broadband access network suitable for high-speed data service access. currently, intelligent community access to the Internet means mainly has following several line access: LAN, ADSL access, CableModem access in order to achieve user access network digital, broadband, and improve user Internet speed, fiber to the home (FILTH) is user network in the future development direction, but because of the cost of fiber-optic user network is too high, in the next dozen years, part of the old residential district will continue to use existing twisted-pair copper loop.

1.1.1 LAN line access

This approach needs to be equipped with high-performance access router equipment, hire of telecommunication sector dedicated to CNNIC for IP address and domain name registration-router can pass DDN line (up to 2.048M bandwidth), FrameRelay, X.25, ISDN dial-up, etc., that are connected to the Internet you can also configure multiple needs flexible WAN port module provides broadband, QoS guaranteed remote multimedia services-local private line access advantage is you can build your own within the community, as a community of Internet households provide comprehensive information services-with technical standards mature, stable and reliable equipment, high security; addIn speed, fast, scalable, high performance price ratio; management simple, easy-to-use and maintenance; can facilitate interconnection with other customers, etc.

1.1.2 ADSL access

Currently, the craze sweeping the ADSL worldwide, the world's major Internet companies have implemented ADSL products and is committed to the development of ADSL, the global number of carriers, ISP also started promoting their respective ADSL services: North America, Singapore and so was the first officially put into operation, Japan, Korea and other countries also entered the pilot phase, China Telecom in Beijing, Shanghai, Guangdong, Fujian and other places have associated network testing and begin pilot promotion, in Shenzhen | also have entered the practical stage, 2001 is the ADSL Go-universal year .ADSL can provide to the end-user 8Mb/s downlink transmission rate and 1Mb/s, uplink transfer rates than traditional 56 k analog MODEM speed is nearly 100 times the. This is the transfer rate of up to 128kb/s ISDN (integrated services digital network), the incomparable .ADSL line with upper and lower speed asymmetric characteristics, therefore, its application is mainly used to provide users with access to the Internet, and VOD services, and does not apply to LAN interconnect service.

1.1.3 the ADSL + ATM/Ethernet "

Client configuration ADSL remote device, the Council configuration DSLAM (ADSL Central Office equipment), they use ordinary telephone twisted pair cable to connect the device to the user of the distal .ADSL PC with Ethernet interface, DSLAM ATM or via fast Ethernet and ISP connected to the network, through the user can achieve broadband Internet access ISP .DSLAM can be placed in a room, through the access network access to the ISP; you can also directly placed in the room, and ISP ISP access platform using LAN directly connected with the use of ADSL VOD business you can use the ADSL + ATM "manner.

1.1.4 CableModem access

In China, the radio and television sector in the cable television (CATV) Internet development of broadband access technologies has ripe and enters the market .CATV network coverage, access of households, the network frequency range, high starting point, most new CATV network using fiber coax networks (HFC), using the above bandwidth 550MHz neighbouring frequency transmission system, very suitable for providing broadband capability business. currently, CableModem access technology in the world especially in the North American Development momentum is very cool, the number of users per year to more than 100 percent growth rate has reached his 10Mb/s downlink rate above, then the higher .CableModem does not require comprehensive wiring, you can take advantage of the existing cable television network as an access network, reduce cost; use of cable television broadcast service, to achieve high-quality signal needs; network equipment according to service the needs of the project gradually amplified, reduce the cost of the initial schema; the network infrastructure can increase as the number of users and user bandwidth demand evolution, no more investment in new networks; main fibre, easy increasing bandwidth demands, in line with the development of multimedia technology.

1.2 intelligent housing community residential external LAN

In order to support and accommodate large amounts of data and multimedia information transfer capability, using the most advanced broadband network technology-intelligent community of the backbone network can be present in the local area network, the most widely used technology, Ethernet, fast Ethernet, FDDI, TokenRing, Gigabit Ethernet, as well as the latest rising of ATM (asynchronous transfer mode), and so on to technology reached the international advanced level course residential external LAN of forms and community needs, building structure and funding of how many are closely related. due to the fast Ethernet and Gigabit Ethernet technology is more mature, both network more. main advantages are:

(1) Intelligent degree requirements, network system requirements lower residential community can make full use of existing networks, such as telephone network, cable TV networks, etc., and wide area networks for simple, low-speed data exchange-which is characterized by low investment, no wiring, but difficult to extend the functionality of the system, cannot meet the functional requirements of user growth, suitable for the completed project of intelligence;

(2) the intermediate and advanced community, should master plan community of wiring system, full use of network resources in the vicinity of the community, the use of HFC (hybrid fiber coax network) or PDS (intelligent building cabling system) outlining the community structure of wiring on the intermediate level, the community-use structured U, I? construct a data network, and the formation of Community internal network platform, providing community information services, and provide a high rate of Internet and VOD services; on advanced community, you can build a community of Gigabit Ethernet or ATM high-speed data network, the best performance of the network, is a good way to protect users of the investment, or you can open a variety of information value-added service, the maximum input of course, but the system can vary with the user requirements of growing gradually opened, this system has the development of a better protection for the owners of the investment, and greatly satisfying user potential needs, have a very high cost performance.

1.3 home local networks

Home local networks, of course, there are several options, such as each household can use Ethernet technology into the system, need a lot of wiring works, if it is a new building, the cable can be embedded, but in old buildings, you elegant, residential building of the effects are time-consuming, costly; telephone line programmes, indoor part also to rewiring; element line electric reliability problems of programmes, but also applications for radio frequency implicated; here, we propose the use of power line carrier spread spectrum of programmes, based on the power line carrier spread spectrum of CEBUS technology is the use of electric powerLine to implement a method of communication, it has the advantage of power line carrier communication, this kind of communication products for success in practice have significant implications and prospects for the new building applications, you can use other communication forms, Stephen Perkins embedded appropriate cables can be considered to be a good choice; but on the as-built premises, using existing power line for household equipment does not have the interconnection, network wiring modification, no need to spend a lot of money, this is the realization of intelligent housing community communications network of local networks of family, a very good model, the economic and social benefits are significant.

CEBUS (ConsumerElectronicsBus, consumer electronic bus, family bus) is a United States electronic industries Association (EIA, ElectronicsIndustryAssociation) for consumer electronics products to develop a communications and product interoperability standards, in 1992 the first release of its first version IS-60 (InterimStandard), and in 1993 and 1994 be amended to EIA/ANIS, open standards, standards (EIA-600) the standards are primarily targeted at families, but not limited to family, defines the communication between the household appliances are used by the communication media and protocols, such as household appliances used for communication between five types of media (power line, radio frequency, infrared, twisted pair and coaxial cable), the signal transmission standard-making follows the same standard of household equipment such as refrigerators, washing machines, microwave ovens, televisions, and the light and so you can plug, and can work together to realize home automation.

Currently, abroad, particularly in North America and Europe, in the context of research and application entered the practical stage has begun, United States of some companies still has introduced the chips and products, for information, military, industrial and home automation; internally, based on fiber-optic cable, cable, and twisted-pair cable for communication media of communication product research and development results and the application has a lot, but in this aspect of the study and application also in its infancy, there are some network products and industrial control products, researchers have noticed that this technology development and application, we developed in this area has been almost two years, will be used in intelligent community of home automation partly network, enabling open power-line plug-and-play functionality.

2 based on the power line carrier spread spectrum communication technology of CEBUS

Spread spectrum communication is will be transmitted in the baseband signal (information data via the usual data modulation of narrow-band signals) by spreading sequence generator generated pseudo-random coding (linear FM waveform) do spread spectrum modulation, frequency spectrum expands to form considerable bandwidth low power spectral density signal transfer, the receiver uses the same pseudo-random coding through relevant treatment recovery into narrow band after demodulation data, recover the original information. different users different pseudo-random coding, but at the same frequency band, the same time work while the spread spectrum communication takes up a larger bandwidth, but spread spectrum communications using CDMA technology spread-spectrum modulation, take full advantage of all the different formats of PN sequence between excellent autocorrelation and cross-correlation characteristics, at the receiving end using correlation detection technology, the despreading is assigned to different users have different formats you can distinguish between different users of the signal, extract useful signal. this average to each user uses frequency calculation, the band brought utilization is very high-spread spectrum of basic four ways: direct sequence spread spectrum, jump spread spectrum, jump spread spectrum and linear frequency modulation.

2.1 direct sequence spread spectrum (Directsequency)

With pseudo-random sequence directly extended spectrum of systems; the sequence of data bit rates far higher than the signal bandwidth of information, the signal of energy evenly distributed to the entire band, at the receiving end using the same local pseudo-random sequence despreading. spread-spectrum modulation available digital am (amplitude shift keying), digital FM (frequency shift keying) and the second phase or four phase-phase shift keying.

2.2 frequency hopping spread spectrum (FrequencyHopping)

Is PRN to select channel-hopping dozens or even thousands of frequencies, from the information codes and PRN's combination control-spread spectrum signals in a frequency through extended periods of time, to represent the data of one, several or a part of, when the signal at a frequency interference, signal can be switched to spread spectrum bandwidth frequency appear within other, thereby significantly reducing the degree of interference.

2.3 time hopping spread spectrum (TimeHopping)

Is a pseudo-random sequence control moment and duration of the time to jump in, a letter code duration divided into several time slots, the pseudo code control in which to send the letter codes in the time slot, the slot selection, the length of duration is also controlled by the pseudo code.

2.4 LFM (Chirp)

Is the emission of radio-frequency pulses in one cycle, the carrier frequency for linear change. because of its frequency in wide-band change signal bandwidth is broadening the. because the LFM occupied bandwidth is much larger than information bandwidth, so there is a spread-spectrum modulation techniques; it uses a series of short, you can synchronize the scan frequency chirps (linear FM waveform) as carrier, each linear FM waveform General continued 100us, it represents the most basic communication symbol time (UST). these chirps covers 100kHz ~ 400kHz frequency bands, and always to 200kHz ~ 400k passes frequencies, then to frequently 100kHz ~ 200kHz end. due to the linear scan chirps signal bandwidth than signal bandwidth to a much larger, and its linear acceleration is relatively high, while the constant-amplitude oscillation wave interference (ContinUous-WaveJamming) frequency acceleration is generally stable, so long as the filter is designed to only a specific angular acceleration signals, CW interference can be excluded. Moreover, this kind of linear FM waveform also has very strong autocorrelation, this kind of fuzzy logic in all of the connections in the decision a device on the network, you can also identify any device from the Internet of this unique waveform, and does not need to send and receive device synchronization.

Use spread spectrum technology carrier can improve system performance, has a strong anti-interference ability, capacity, anti-noise multipath interference capability, the ability to resist fading and confidentiality, etc.

United States Intellon Corporation PL series is the use of these chirps (linear FM waveform) scan frequency carrier to be spread spectrum signals. sending, the linear frequency modulation waves as carrier to treat the transmission of the baseband signal (information data narrowband signal) for spread spectrum modulation, frequency spectrum expands to form considerable bandwidth low power spectral density signal, through output amplifier and media-free in-circuit transmission to the media; when it is received on the power line frequency l00kHz ~ 400kHz analog signal through tricks-/filter network traffic to enter the filter on the receiving end using the same encoding for demodulation and associated processing, restore the original information. its products comply with United States electronic industries Association (EIA) developed by the consumer
E-bus standard, (CE.BUS) EIA-600. we choose Intellon Corporation based on power line communication components and interface devices SSCP300/200, developed based on the power line carrier SS CEBUS communications transceiver is the intelligent network infrastructure for the local network in the family a good choice.

3 power line carrier spread spectrum communication technology in intelligent housing community communications network mode

Here the recommended is based on the power line spread spectrum as a family of local network intelligent housing community network programme, overall network architecture is divided into three layers: Internet access networks, intelligent housing community residential external LAN using a phone line or Ethernet, in residential local network uses within the Home Powerline transmission.

3.1 House of all sorts of information transmission parts

This part of the communication medium is a selection of core power-chip is Intellon's power line carrier chip SSCP300 spread-spectrum, the chip has sent and received two functions, the collector has SSCP300 and relevant A/D and D/A converters, collector and A transceiver (or transmitter B) communication, this communication is in both directions.

A 3.2 transceiver (or transmitter B) and community center of computer communications section

If there is a residential community, through Ethernet transceiver with B and the Central Administration of computer communication, if the network cable is to the home, then through the transceiver with telephone lines and A center of computer communications transceiver chip inside A SSCP300 and Modem, SSCP300 responsible and House of individual collector communication, Modem is responsible for the management of computer and communications transceiver B there SSCP300 chip and Ethernet communications chip, the Ethernet communication of the chip is responsible for and management of computer communications.

3.3 community center of computer and Internet communications section

You can use any one of the previously described ways to access, this can be done by the Office and the car's computer, or mobile Internet access, computer management, and further control home appliances.

This system includes the remote meter reading system, family security subsystem and home automation subsystem. Community Management Center computer can read four tables of data; in case of fire, gas leak, window glass was broken when alarm; master over the Internet to remote control home appliances, such as into the door open air conditioning, lighting, etc.

4 closing

Spread-spectrum based on power line carrier communication, due to its technical characteristics and some of the advantages, not need to rerun the network wiring, this is a smart community network infrastructure in a local network of the family a good choice, with broad prospects and markets.

Source: Shenzhen third Mong communication technology co., Ltd.