【 Weak current College 】 wireless connectivity technology: Digital family core

Digital home each device is available through wireless connection technology to achieve interoperability, and the present existence of household electrical appliances essential differences. Therefore Wi-Fi, Bluetooth, ZigBee, and so can get different data transfer rate and distance of a variety of technology also for furniture in different scenarios.

Digital home concept and prototype of a few years ago by electronic and IT technology pioneers, mainly to refer to a kind of home appliances, PC, mobile devices, sensors and security monitoring equipment consisting of a fully automated network; all terminals are uniform or compatible communications technology to achieve seamless transparent connection. For example, each room can receive a computer's audio and video, and pictures; the whole home environment are wireless network coverage; cameras, mobile phones and other mobile devices can send files to a PC; housing internal wireless sensor network (WSN) according to the environment of density and position adjustment of temperature and lighting, but outside of the sensor is a possible security risk (such as illegal intrusion, etc.) issued a warning. Digital home each device is available through wireless connection technology to achieve interoperability, and the present existence of household electrical appliances essential differences. Therefore Wi-Fi, Bluetooth, ZigBee, and so can get different data transfer rate and distance of a variety of technology also for furniture in different scenarios.

Controversial UWB

UWB (ultra wide band Ultra-Wideband,) is an efficient low power broadband without carrier communication technology, and traditional radio technology significantly differ, the latter through the change of a sine wave power level, frequency or phase, etc.; and the UWB transmission of information without using the carrier, its at a specific point in time generate pulse radio energy and occupy a larger bandwidth for pulse position (Pulse-Position) or temporal modulation (Time-Modulation), so power consumption is significantly reduced. UWB is a non-traditional application collaborative radar (Non-CooperativeRadar) imaging, data acquisition, high precision positioning and target tracking, etc. In everyday applications, due to the States to signal emission level restrictions, UWB positioning in response to Sprint's indoor wireless applications such as wireless display technology and cameras, wireless printing technology, wireless audio transmission, etc. Allegedly in the second half of 2008 will introduce UWB and Bluetooth integration standards for different size data transmission efficiency.

UWB technology has pushed for IEEE802.15.3a personal area networks (PAN, PersonalAreaNetwork) to draft standard, but after several years of time yet to see any progress, the entire process nearly stalled in 2006, the Working Group declared dissolved IEEE802.15.3a. The main reason is that although the transfer means UWB great advantage, but it is difficult to solve. Implemented by UWB data transfer and single-band of traditional narrowband or continuous carrier without too much interference, but research shows that a large number of UWB transceiver will make noise levels increased significantly, to the distribution system a significant burden and affecting its stability, and some test results also show whether the transfer rate, or the transmission distance is much lower than expected. 2006 based on UWB technology Belkin Wireless USBHub tests, transfer rate does not exceed the scope, but also through 6.35Mbps is only a few feet, and then claimed that the distance of 30 feet and a far cry from 480Mbps rate. Broadcom (BroADCom), General Manager of the company's greater China, Yi-liang considers a major dilemma is UWB transmission distance and speed, the second is a antijamming, but lack the support of the network function, several factors lead to this result. You can currently has no other alternative technologies, Wi-Fi in this regard began to be optimistic about. But many analysts believe that Belkin product testing is not a certification test, the test of correctness debatable, test failure can only explain the product Belkin cannot achieve the requirements, not necessarily the technology itself.

Will become home Wi-Fi network standard

Wi-Fi and UWB, ZigBee, Bluetooth, etc. for different PAN technology positioning, mainly for the wireless LAN connection. According to the draft IEEE802.11n Edition, speed of up to 200Mbps, adequate bandwidth can be easier to the Internet browsing and transfer files between your computer and data.

Liang yi think Wi-Fi functionality in the network has been very mature, the transfer rate is relatively satisfactory course 802.11a/b/g only tens of megabytes of bandwidth or obvious enough, will determine the final 802 .11n standard and MIMO will very suitable for such applications; and in the commercial context, its software technology increases the likelihood of value-added services. Currently include Broadcom, manufacturers are trying to bring 802.11n to consumer electronics, one of the difficulties is that its data transfer reliability. In the United States the problem is still not very prominent, because their housing structure mainly wood, so the data transmission is relatively simple, but in China and Asia Pacific with cement and concrete-building is even more difficult, and Broadcom is therefore as a research direction. It cannot be said that the future will become 802.11n home wireless network standards, but it now seems that compared with other technologies, is a leading 802.11n.

In addition to the different environmental transmission performance difference, the power consumption is also a predicament Wi-Fi. And PAN the technology Wi-Fi distance farther, hence the need for higher power consumption; whereas the constant radiation power, Wi-Fi device performance will appear as the distance increases geometrically. ThomasEmblaB NordicSemiconductor product managerOnnerud that limit the Wi-Fi bottleneck is its relatively high power consumption, while battery technology advances, Wi-Fi increasingly used to portable devices such as PDAs and mobile phones, etc. However, Wi-Fi power larger concerns not just on the battery capacity will be able to solve, if you use frequently, the battery may soon run out.

Wibree: Bluetooth substitutes?

Bluetooth (Bluetooth) is one of the important technical PAN, which was officially launched in 1998, its purpose is to serve as a short range communication protocol used to replace the connection of portable and stationary devices, the original data cable transfer rate to 1Mbps or 3Mbps (EDR, i.e. enhanced data rate), the role of the distance around 10m. Mass production of the latest version is version + EDR Bluetooth 2.0 (while 2.1 + EDR nearing commercialization).

2001 Nokia researchers see Bluetooth technology does not cover all the needs of wireless applications, especially for low-power applications, started with name "BluetoothLowEndExtension (Bluetooth low expansion technology)" research and development. The technology is still based on Bluetooth, but lower power consumption and costs. After a series of partner development work, which in 2006 was officially launched, the trade name changed to Wibree and set up the corresponding Union. Wibree technology enables application is no longer restricted to larger batteries (rechargeable or AA), and to extend the scope of the wireless connection, includes medicine, watches, toys, sports goods and thousands of other consumer products. Subsequently, the not-for-profit industry organization BluetoothSIG (Bluetooth technology Alliance) in 2007 will ULP Bluetooth-Wibree is defined as (Ultra-Low-PowerBluetooth).

Wibree products can be realized than Bluetooth smaller and more efficient battery usage. CR2032 is a lot of ultra low-power applications of choice for power, the battery can be used with Wibree product, while Bluetooth devices cannot, because of the battery capacity is limited, approximately only 220mAh, maximum current at 20mA or so. ThomasEmblaBonnerud said, Bluetooth power consumption with the run mode changes, the current Bluetooth 2.0 + EDR device, if the master and slave transmission capacity between all applications, power consumption will rise to about 35mA ~ 45mA; simply synchronized can be dropped to 5mA ~ 10mA; work in static mode, power consumption drops to µA of magnitude. In a data flow-audio applications, such as MP3 players and headphones, rechargeable lithium ion battery discharge time about 10 hours, with a wireless mouse in two AA batteries can use approximately 100 hours.

The emergence of Wibree was not intended to replace Bluetooth, which is an important complement of Bluetooth technology. But the Marketing Director at BluetoothSIG AndersEdlund asked the organization how to understand this technology, for what is Bluetooth-Wibree supplementary or competitors of problems often have some of the discussion, I think these two possibilities exist simultaneously. ThomasEmblaBonnerud believes that Wibree specification is still in draft stage, how long does it take to be approved as a standard in the mass market, on the project often pessimistic attitude. Bluetooth technology uses seven years implementation of mature; but I think that the current market based on Bluetooth, the popularity of the shall Wibree will be faster.

So you can see, although the Wibree creators are avoided and the ambition of Bluetooth competition, but if you can in the same frequency to achieve better interoperability and lower power consumption and costs, users and manufacturers the ultimate Wibree and Bluetooth discard outdated is an inevitable market.