預測是件很有意思的事。一半的預測都是錯的，特別是在技術領域。比爾·蓋茨有一項很著名的預測，那就是沒有人會開發出32位操作系統。1943年，IBM董事長托馬斯·沃森說：“我覺得全球計算機市場的規模可能是5臺。”另外，誰能忘得了iPhone問世時微軟首席執行官史蒂夫·鮑爾默的預測呢：“iPhone的市場份額根本不可能有多大。”

“預測未來很容易；難的是預測正確。”這句諺語是有道理的。因此，最近出現的Wi-Fi將消亡的預測引發懷疑并不意外。

無限數據方案、各式各樣的LTE-U、市民寬帶無線電服務（CBRS）以及5G的出現都被急火火地視為潛在的Wi-Fi殺手。然而，盡管在快速發展的無線通信領域任何事情都有可能，但借用馬克·吐溫的一句話，說Wi-Fi已經死了，是極度的夸大其詞。

2006年以來，思科的年度可視網絡指數（VNI）一直是預測蜂窩和Wi-Fi網絡流量的黃金指標，其準確性獲得了普遍認可，而且被視為研究無線通信行業的全球標準。

最新的VNI預計，2021年全球公共Wi-Fi熱點總量將是2016年的6倍。單北美地區就會有大幅增長，到2021年公共Wi-Fi熱點數量將增長3倍，達到9370萬個。此外，市場研究機構Markets and Markets預計，作為服務，到2021年Wi-Fi市場規模的年均復合增長率為38%。

如果說Wi-Fi是即將被一顆巨大小行星毀了的恐龍，那么所有主要行業分析師就都遺漏了這個問題。

實際情況是僅憑LTE不可能應付流媒體和共享等帶寬密集型活動產生的海量數據。在機場和體育館等人群摩肩接踵的高密度地區尤其如此。這樣的環境下手機信號很差，難以有效保持帶寬，這就讓Wi-Fi成了可以跟LTE抗衡的較可靠解決方案。

在如今的重要地點，蜂窩和Wi-Fi網絡均并行存在。電信運營商用Wi-Fi來滿足巨大的移動數據需求。Sprint目前正在將用戶的LTE流量轉移給Wi-Fi，預計將有更多通信公司布其后塵。思科的2017年VNI預計，到2021年，64%的智能手機流量和72%的平板電腦流量將轉移到Wi-Fi網絡。

市場咨詢機構ABI Research認為，物聯網開始嶄露頭角也會給Wi-Fi帶來有利影響。

預計到2025年，物聯網每年將產生11.1萬億美元的經濟影響。這可是萬億美元。Wi-Fi是物聯網設備的生命線。愛立信最近公布的數據顯示，到2020年蜂窩網絡的覆蓋面可能不到北美物聯網的15%。絕大多數物聯網都可能在非授權類通信技術的支持之下。目前，Wi-Fi連接著家庭中的所有設備——Alexa語言助手、電燈、Sonos音箱和門鈴，所有大家能想到的東西。今后，在制造、交通運輸和公用事業等領域，Wi-Fi還可能成為所有使用物聯網的企業做出變革的必須手段。

和傳統LTE相比，Wi-Fi的基礎設施成本較低，延遲較短，吞吐量較大，可以服務于所有電信運營商的終端，而且較容易部署。這讓Wi-Fi成了室內必備網絡，無論是在家里，在寫字樓，還是在工廠。

無限移動數據方案將宣告Wi-Fi之死的預期從1995年就開始了。3Com創始人羅伯特·梅特卡夫當時說：“我覺得互聯網很快就會出現大爆發，但會在1996年出現災難性崩潰。”還記得幾年前嗎？那時蜂窩網絡不限流量，但消費者還是選擇用Wi-Fi。此外，數以億計的設備都沒有LTE連接，它們都需要Wi-Fi。

Wi-Fi在5G和CBRS等技術領域也有一席之地。

5G是4G的同胞兄弟。作為最新移動通信標準，它更年輕、更快、更強大。雖然預計到2020年以后才會出現，但5G的速度將遠遠超過4G，理論下載速度可達到每秒1萬Mb。那么大家就會問了，5G已經那么快了，我們為什么還需要Wi-Fi呢？

5G將基于多個頻段的累加。無線通信行業基本上已經同意把LTE、Wi-Fi以及其他未授權類通道都融合在一起。如果授權類（LTE）和未授權類（Wi-Fi）頻段不能共存，5G從經濟上講就不可行。換句話說，5G并不側重于哪種技術，它是一個整合型網絡，通過更多的頻段來吞吐更多數據。

然而，5G系統開始部署時，下一代Wi-Fi，也就是802.11ax也將可以投入市場。11ax的加持將極大提升Wi-Fi網絡的效率。更具體地說，11ax將解決此前Wi-Fi技術缺乏上行鏈路調度的問題，人們一直強調，這種能力是未授權類頻段使用LTE網絡后形成的3GPP生態系統的主要好處之一。也就是說，隨著802.11ax的推出，3GPP和IEEE 802.11 MAC兩種技術標準的差異就會消失。

CBRS取代Wi-Fi的說法也會讓人產生被誤導的預期。這兩項技術相互補充。可以把CBRS視為使用3.5GHz頻段的Wi-Fi，而Wi-Fi使用的是2.4 GHz和5 GHz頻段。基于LTE的CBRS解決方案可實現戶外最大覆蓋，這就有了經濟性，而Wi-Fi仍將適于企業市場和家庭網絡。值得注意的是，在現有頻段部署CBRS的做法主要可用于美國市場，而且其成本要比Wi-Fi高得多，因為CBRS需要用新的LTE設備全面重建基礎設施。

客觀地說，Wi-Fi確實有缺點。公共網絡帶來安全顧慮，使用公共網絡所需的用戶名/密碼登錄過程也不讓人滿意。Passpoint等新技術提供了最高級別的公共Wi-Fi加密，解決了令人討厭的登錄問題，而且不需要用戶干預就可在LTE和Wi-Fi之間來回切換。

1966年，《時代》雜志做了一次著名預測：“雖然完全可行，但遠程購物會徹底失敗。”雖然用了40年才起步，但“遠程購物”現在已經站住了腳。Wi-Fi的情況也是如此。更明確地說，在如今的通信領域和明天的融合世界，授權類和未授權類頻段都需要一席之地，而且最為確定的是，Wi-Fi將是其中的一部分。就像LTE不斷發展一樣，Wi-Fi也將不斷進步，從而支撐起一個無縫連接的世界。

Wi-Fi不會死。Wi-Fi萬歲。（財富中文網）

譯者：Charlie

審稿：夏林

德里克·彼得森是移動網絡連接服務提供商Boingo Wireless首席技術官以及科羅拉多理工大學客座教授。

Predictions are a funny business. Odds are you’re going to be wrong half the time—especially when it comes to technology. Bill Gates famously predicted nobody would ever make a 32-bit operating system. Thomas Watson, chairman of IBM, said in 1943: "I think there is a world market for maybe five computers.” And who can forget former Microsoft CEO Steve Ballmer’s prediction when the iPhone launched: “There’s no chance that the iPhone is going to get any significant market share.”

There’s a reason for the adage “Predicting the future is easy; getting it right is the hard part.” So it comes as no surprise that skepticism abounds surrounding the recent predictions that Wi-Fi will go the way of the Dodo.

Unlimited data plans, LTE-U with all its flavors, Citizens Broadband Radio Service (CBRS) and the rollout of 5G have all been trotted out as potential Wi-Fi killers. And while anything is within the realm of possibility when it comes to the fast-moving wireless space, to borrow a line from Mark Twain, the reports of Wi-Fi’s death have been greatly exaggerated.

Since 2006, Cisco’s annual Visual Networking Index (VNI) forecast has been the gold standard for cellular and Wi-Fi traffic projections. It’s widely respected for its accuracy and is considered the global standard for research in the wireless industry. As Cisco’s says, it's projections have been accurate within 10% over the last 11 years.

Cisco’s latest VNI predicts that globally, total public Wi-Fi hotspots will grow 6-fold from 2016 to 2021. In North America alone, the growth will still be significant, spiking 4-fold to 93.7 million by 2021. In addition, Markets and Markets has pinpointed a CAGR of 38% for the Wi-Fi as a Service market size by 2021.

If Wi-Fi is a dinosaur about to be destroyed by a giant asteroid, every major industry analyst missed the memo.

The reality is it is not possible for LTE alone to handle the onslaught of data caused by bandwidth-intensive activities like streaming and sharing. This is especially true in high-density locations, such as airports and stadiums, where people are sitting “hip to hip." Cell signals struggle in these environments to effectively transport enough bandwidth, making Wi-Fi a more reliable solution that can complement LTE.

Cellular and Wi-Fi are already deployed alongside each other in large venues today. Carriers leverage Wi-Fi to accommodate the tremendous demand for mobile data. Sprint currently offloads customer LTE traffic over to Wi-Fi and more carriers are expected to follow suit. Cisco’s 2017 VNI predicts the amount of traffic offloaded from smartphones to Wi-Fi will be 64% by 2021, and tablets at 72%.

Wi-Fi will also see a positive impact from the dawn of the Internet of Things (IoT), according to ABI Research.

By 2025, IoT is estimated to have an economic impact of $11.1 trillion a year. Trillion. Wi-Fi is the lifeblood for IoT devices, with recent data from Ericsson suggesting that cellular-based networks could be used to provide less than 15% of overall IoT connectivity in North America by 2020. The vast majority of IoT could be supported by unlicensed technologies. Today, Wi-Fi connects all the devices in a person’s home—Alexa, lightbulbs, Sonos, doorbells, you name it. Tomorrow Wi-Fi could be a go-to for revolutionizing the IoT-powered enterprise across manufacturing, factories, transportation, utilities and more.

Compared to traditional LTE, Wi-Fi has a lower cost of infrastructure, reduced latency, more throughput, can serve all endpoints respective of carrier affiliation, and is easier to deploy, making it the must have for indoor coverage, whether it’s for a home, office building or industrial plant.

Hearing predictions that unlimited mobile data plans will be the cause of Wi-Fi’s demise hearken back to 1995, when Robert Metcalfe, the founder of 3Com said, “I predict the Internet will soon go spectacularly supernova and in 1996 catastrophically collapse.” Remember a few years ago when cellular plans used to be unlimited—and consumers still turned to Wi-Fi? In addition, billions of devices don’t have LTE connectivity; they need Wi-Fi.

Wi-Fi also has a place in technologies like 5G and CBRS.

5G is 4G’s younger, faster, and stronger brother—the next and newest mobile wireless standard. While 5G isn't expected until 2020, it will be significantly faster than 4G, allowing for a theoretical download speed of 10,000 Mbps. So if you’re wondering if that is fast, why do we need Wi-Fi?

5G will be based on the unified aggregation of multiple bands. The wireless industry has largely accepted that this will include the convergence of LTE and Wi-Fi or other unlicensed channels. 5G is not economically practical without coexistence between licensed (LTE) and unlicensed (Wi-Fi) spectrum. In other words, 5G does not prefer one technology over another, but rather one consolidated network that handles more data with more spectrum.

However, by the time 5G systems start getting deployed, the next generation of Wi-Fi, 802.11ax, will be ready for market. 11ax enhancements will significantly increase the efficiency of Wi-Fi networks. More specifically, 11ax will address the lack of up-link scheduling in previous versions of Wi-Fi, a capability that has been highlighted as one of the primary benefits in the 3GPP ecosystem of LTE operation in unlicensed bands. This would suggest that the divergences between 3GPP and IEEE 802.11 MAC designs are set to diminish with the introduction of 802.11ax.

The argument of CBRS’ takeover of Wi-Fi also brings a misinformed perspective. The technologies are complementary. CBRS can be viewed as another band of Wi-Fi, operating in the 3.5 GHz unlicensed channel alongside Wi-Fi at 2.4 GHz and 5 GHz. LTE-based CBRS solutions can maximize outdoor coverage where it makes economic sense, whereas Wi-Fi will remain the suitor for connectivity in the enterprise market and at home. It’s worth noting that the deployment of CBRS with the current defined spectrum is primarily available for the U.S.market and that it comes at a much higher cost than Wi-Fi, as it will require facilities to overhaul infrastructures with new LTE equipment.

To be fair, Wi-Fi does have its shortcomings. Public networks bring to bear security concerns and an unsatisfactory log-in process of user names and passwords when using public networks. New technologies like Passpoint offer the highest level of public Wi-Fi encryption and solve tedious log-in requirements, switching devices back and forth from LTE to Wi-Fi without user intervention.

Back in 1966, Time Magazine famously predicted, "Remote shopping, while entirely feasible, will flop.” While it took another 40 years to really take off, “remote shopping” is here to stay. The same is true of Wi-Fi. To be clear, both licensed and unlicensed spectrum need a seat at the table in the connected world of today and the converged world of tomorrow. But Wi-Fi will most certainly be part of that equation. Even as LTE evolves, Wi-Fi too will evolve to power a seamlessly connected society.

Wi-Fi is not dead. Long live Wi-Fi.

Derek Peterson is chief technology officer of Boingo Wireless. He is also an adjunct professor at Colorado Technical University.