【 Weak current College 】 M2M rooted smart home wireless technology

Wireless network technology and wireless control technology and the rapid development, accelerates "wired world" to "wireless space" of rapid development. M2M technology advanced concepts will lead to a new round of "wired" wireless "world revolution".

M2M offers equipment for real time data between systems, remote device, or personal wireless connection is established between a simple means, comprehensive data collection, remote monitoring, telecommunication, information technology, to enable the automation of business processes; integration of company IT systems and non-IT equipment in real-time, creating value-added services. This platform is available in the security monitoring, auto read parking meter, mechanical services and repair operations, vending, public transportation system, fleet management, industrial process automation, electrical machinery, information of the application in the environment, providing a wide range of applications and solutions. M2M technology has been CA, HP, Intel, IBM, AT & T, EriCSSon, Nokia, OMRON, big-time Opto22 and vendor support.

M2M technology and the use of traditional ground-based telephone line or wireless radio remote monitoring system works, and is likely to replace the latter. Analysts said as M2M system does not need to connect to remote areas of the equipment set up hundreds of miles of telephone lines and resolve the wireless radio for distance and frequency bands, thus more suitable and more convenient.

In M2M, GSM/GPRS/UMTS is a major long distance connection technology, close the join technology mainly 802.11b/g, Bluetooth, Zigbee, UWB, and RFID.

1. wireless local area network (WLAN)
IEEE802.11 wireless LAN international standards published in June 1997, this is an open standard. Use of 802 .11b and 802.11a, wireless network standards, can make you in a variety of complex environments (like crowded Office, campus, buildings, restaurants and even entire blocks), you can achieve seamless non-stop connections. Through the use of wireless local area network (WLAN) in the whole community or household indoor share a broadband Internet connection, you can avoid the use of cables, routers and other devices brought trouble, customers simply access points into the broadband modem, wireless network card is installed in their network and desktop, you can enjoy wireless broadband Internet access has advantages.

2. Bluetooth
In M2M, Bluetooth technology as a short-range wireless connectivity technology that has broad application prospects. New Bluetooth standard 2.0 intends to support up to 10Mb/s above rate (4, 8 and 12Mbit/s ~ 20Mbit/s), it is estimated that in 2004 and beyond, this is the future more and more broadband multimedia business requirements of evolution. Because of Bluetooth technology you can easily embed a single CMOS chip, therefore, particularly suitable for small mobile devices, so that devices through wireless communication, avoid the inconvenience of the connecting cable.

Bluetooth technology works at global common 2.4GHzISM band. In theory, to run technical 2.4GHzISM band can use from within the device 30m connected to each other, but in reality it is difficult to achieve. At this stage, the Bluetooth transmitter range, you can simultaneously achieve 10m 8 units of Unicom. When the distance is less than 10m is detected, the receiving device can dynamically adjust function; when volume decreases or stops, the Bluetooth device to enter low power mode.

Bluetooth technology applications in smart home, have a high reliability, low complexity, low power, low-cost advantages, but there are still some issues that need to be addressed, such as between adjacent devices to prevent misinformation and intercepted, require the user to set the corresponding frequency band in advance; Bluetooth chip prices higher; Bluetooth module is more difficult to produce, etc. But it is believed that, along with the Bluetooth network appliances, and networking equipment, home of the further popularization of intelligent, these problems are gradually being resolved, and Bluetooth wireless smart home systems will also be given to the future of family life a tremendous revolution.

3.ZigBee
In order to meet the low power, low-cost wireless network requirements, IEEE Standards Board in December 2000, officially approved and established working groups, task 802.15.4 is to develop a low data rate of WPAN (LR-WPAN) standards. It has a low complexity, cost extremely little, power consumption, very small features that low-cost devices (fixed and portable or removable) for low data rate transmission. Based on this standard wireless network can be used without permission of 858MHz, 902MHz ~ 928MHz and 2.4GHz wireless band, can be reached 20Kbps, 40Kbps and 250Kbps maximum data transfer rate.

802.15.4 wireless transmitter/receiver and network are Motorola, Philips, Eaton, Invensys and Honeywell International communication and industrial control sector giants is highly respected throughout the world. It meets the international standards organization (ISO) Open Systems Interconnection (OSI) reference model. It includes the physical layer and media access layer, network layer and senior. Below is a description of these layers.

ZigBee has the following advantages:
1) electricity: two batteries can work 6 months to 2 years or so, eliminating the charge or frequent replacement battery trouble.
2) network capacity: will accommodate up to 255 devices.
3) low cost: compared with other technical features with inexpensive, and ZigBee Protocol waive patent fees.
4) delay short: typically 15ms delay are in ~ 30ms.
5) security: provides authentication capabilities while the flexibility to determine its safety properties.

The Working Group is responsible for formulating IEEE802.15.4 physical layer andMAC layer protocol, and the remaining agreement main references and adoption of existing standards, network layer above Protocol developed by the ZigBee Alliance.

Implement ZigBee's request is very simple, as long as 8-bit processor and diary ROM, but requires more RAM for storage of all nodes in the device information, such as the associated table and password. ZigBee offers low-rate, low cost, long-life equipment solutions, and it works without the need to apply for the frequency band, to be able to override the device very much larger, communication. As a well-known IEEE802 family, ZigBee will make a very good market effect.

4.GPRS/GSM1XRTT/CDMA
GPRS (GeneralPacketRadioService), general packet radio service, is within the existing GSM system developed from a new grouping data hosting business. GPRS and GSM system the most fundamental difference is that the GSM is a circuit-switched systems, GPRS is a packet switching system. GPRS is especially suitable for continuous, sudden or frequent, a small amount of data transfer, also applies to the occasional large amount of data transferred. GPRS can be understood as GSM a higher level.