作為一種無線電技術(shù)，Wi-Fi讓數(shù)碼設(shè)備不需依靠蜂窩網(wǎng)絡(luò)就能連接互聯(lián)網(wǎng)。用不了多久，我們新購入的數(shù)碼產(chǎn)品就能使用一種新型Wi-Fi了。這種新型Wi-Fi并非為這些數(shù)碼產(chǎn)品專門設(shè)計(jì)，而是為我們家里，甚至我們身上的互聯(lián)設(shè)備網(wǎng)絡(luò)量身打造的。這些設(shè)備都將是物聯(lián)網(wǎng)的組成部分。

Wi-Fi聯(lián)盟把這種新標(biāo)準(zhǔn)稱為Wi-Fi HaLow（發(fā)音為“哈嘍”），稱其傳輸距離是傳統(tǒng)Wi-Fi的兩倍，耗能也有所降低。當(dāng)下，構(gòu)建智能城市的主要是專有標(biāo)準(zhǔn)化網(wǎng)絡(luò)和蜂窩網(wǎng)絡(luò)，而可穿戴設(shè)備的個人網(wǎng)絡(luò)則由藍(lán)牙無線主導(dǎo)，Wi-Fi聯(lián)盟很樂于看到Wi-Fi成為這些領(lǐng)域的新標(biāo)準(zhǔn)。

到目前為止，Wi-Fi聯(lián)盟在新標(biāo)準(zhǔn)的耗電量、傳輸距離和傳輸數(shù)據(jù)量大?。ㄋ俣龋┑燃?xì)節(jié)上語焉不詳。他們只透露這種新標(biāo)準(zhǔn)將使用900兆赫茲的頻率，這一頻段目前屬于未授權(quán)頻段，被用于微波爐、嬰兒監(jiān)控器和其他無線設(shè)備上。這意味著Wi-Fi將會有三個工作頻段：2.4GHz頻段、5GHz頻段和900MHz頻段。

然而，HaLow現(xiàn)在和未來都只會有900MHz這個工作頻段。這主要是因?yàn)檫@個頻段在穿透墻壁和遠(yuǎn)距離傳輸方面表現(xiàn)出色，滿足了“遠(yuǎn)距離傳輸”的前景，不過在耗能上，人們依舊莫衷一是，因?yàn)檫@也是Wi-Fi應(yīng)用于物聯(lián)網(wǎng)的最大問題。許多物聯(lián)網(wǎng)設(shè)備都是電池供電，而Wi-Fi則是著名的電量殺手，也就是說大部分廠商都不會在感應(yīng)器、可穿戴設(shè)備、以及其它無法安裝大型電池卻需要長時間工作的設(shè)備上使用Wi-Fi。

當(dāng)HaLow2015年以802.11ah【這是電氣與電子工程師協(xié)會（IEEE）的標(biāo)準(zhǔn)名，而不是Wi-Fi聯(lián)盟的品牌名】的名字開發(fā)時，幾家芯片公司的工程師對它宣稱的低能耗半信半疑。Moor Insights and Strategy公司的分析師帕特里克?摩爾海德表示：“聯(lián)盟對細(xì)節(jié)的表述不太清楚，所以，我有點(diǎn)懷疑他們能否實(shí)現(xiàn)功耗和傳輸速度的目標(biāo)，否則，他們就是在吹牛了?！?/p>

不過Wi-Fi聯(lián)盟確實(shí)公布了HaLow的數(shù)據(jù)傳輸速率，大約是每秒150KB到18MB，這比傳統(tǒng)的Wi-Fi要慢得多。如果帶寬足夠，傳統(tǒng)Wi-Fi的傳輸速率可以達(dá)到每秒1GB。一般來說，耗能越高、干擾越弱，數(shù)據(jù)傳輸速率就越快。考慮到一般的家庭環(huán)境中，900MHz頻段的使用量就如同早上7點(diǎn)星巴克的人一樣多，所以想要保持高速率可能很難。當(dāng)然，在物聯(lián)網(wǎng)中沒必要傳輸大量數(shù)據(jù)，所以，這一點(diǎn)可能并不太重要。耗能、可靠性和傳輸距離才是更重要的指標(biāo)。

這一標(biāo)準(zhǔn)直到2018年才會正式使用，不過相關(guān)設(shè)備將會在今年晚些時候面世。我們很快就能看到Wi-Fi HaLow究竟有多么強(qiáng)大和實(shí)用。（財(cái)富中文網(wǎng)）

譯者：嚴(yán)匡正

審校：任文科

Soon your new gadgets will come with a new flavor of Wi-Fi, the radio technology that allows your digital devices to connect to the Internet without blowing through your cellular data cap. This new version isn’t designed for these gadgets, however. Instead, it will be made for the network of connected devices in your home ― and even on your body ― that make up the Internet of Things.

The Wi-Fi Alliance calls this new standard Wi-Fi HaLow (pronounced halo), and says it doubles the distance and cuts the power consumption of traditional Wi-Fi. The Alliance would like to see Wi-Fi become a standard in smart cities where proprietary standards and cellular networks currently reign supreme, and in personal area networks for wearable devices where Bluetooth radios are used now.

So far, the Wi-Fi Alliance is being pretty vague on the details about the new standard in terms of how much power it will consume, how far it will travel, and how much data it will be able to transfer (and how quickly). It does say that the new standard will use the 900 megahertz spectrum, which is currently unlicensed and used by microwave ovens, baby monitors and all sorts of other wireless devices. This means Wi-Fi will now work in three bands; the 2.4 GHz band, the 5 GHz band and the 900 MHz band.

However, HaLow only works in the 900 Mhz band and will do so primarily because that band is great for penetrating walls and going further. So that covers the ‘going the distance’ part, but the jury is still out on the power consumption part, which is where Wi-Fi has really suffered when it comes to the Internet of things. Many of these devices are powered only by batteries, and Wi-Fi is a notorious power suck, which means that most manufacturers don’t use it on sensors, wearables and other devices that don’t have room for a large battery, but are expected to last a long time without a recharge.

When HaLow was being developed around last year as 802.11ah (that’s the IEEE version of the standard as opposed to the Wi-Alliance brand), several engineers at chip companies expressed concern over its claims about being low power. “The Alliance is being a bit vague with the details so I’m a bit skeptical that they will hit their power and speed goals. Otherwise they would be touting the accomplishment,” says Patrick Moorhead, an analyst with Moor Insights and Strategy.

It did, however, provide data rates for HaLow, which are between 150 kilobits per second and 18 megabits per second, which is much less than the traditional Wi-Fi rates (which are hitting up to a gigabit if the underlying broadband speeds are fast enough). Generally, you’ll see faster data rates at higher power consumptions and when there is less interference. Given the average home environment where 900 Mmz is the spectral equivalent of a Starbucks at 7AM those fast rates may prove difficult. Of course, with the Internet of Things, transmitting large amounts of data isn’t necessary, so that may not matter. Power consumption, reliability and distance could be more important.

The standard won’t be official until 2018, but devices will be out later this year. We’ll soon see how robust and useful Wi-Fi HaLow really is.