美國紐約大學理工學院（NYU Polytechnic）的研究人員Theodore Rappaport呼吁，主管機關應該開放毫米波（millimeter wave）頻段的授權，以迎接無線通信領域的技術復興。

Rappaport預見，28~90GHz頻段網絡可替未來的的移動設備提供Gbps等級的資料傳輸；他的技術研究中心已經在進行一些技術概念的測試，但還需要更大規模的努力。

Rappaport在接受EETimes美國版編輯專訪時表示，“電信營運商需要有個測試場，來開發各種能運用在28GHz、38GHz與79~90GHz頻段的產品原型；在該領域已經有很多相關研發活動，我只擔心美國會在其中落后。”

他認為，美國聯邦通信委員會（FCC）應該針對研究用途以及一些移動應用程式的輕度商業化開放上述頻段，“韓國與中國都已經看到相關商機，而且顯然在開放毫米波頻段給蜂窩移動通信應用方面有較開放的態度。”802.11ad標準60GHz WLAN技術是一個開端，而仍在開發階段的未來5G移動通信，將會讓該頻段繁榮發展。

Rappaport表示，5G 將采用智能天線技術--將數百個像沙粒般微小、以高介電材料制作的天線元件一起定相（phased），并灑進智能手機中，“相控陣已經被運用在許多高成本軍事系統中，要將該技術帶到消費性電子產品上，我們還面臨一些技術性問題。”

在另一方面，5G技術需要全新的無線路由器與中繼器（repeater），這也將為網絡帶來智慧功能；Rappaport指出，未來距離200~400公尺遠的基站通過快速結合波束，聯合在一起提供寬頻連結。他的研究中心已經建立了一個紐約市內毫米波信號傳播特性的資料庫，吸引了包括AT&T、Intel、Samsung等企業贊助。

Rappaport表示，“我們的研究展示了在都市環境中反彈能量（bouncing energy）的方向性天線，能形成良好的蜂窩連結，而且在某些方面表現比如今的蜂窩網絡更好。”其研究中心接下來將開發統計模型以及頻道仿真器，做為5G系統與標準的測試平臺；那些工具將協助網絡服務業者進行成本估算，以及規劃毫米波城市通信網絡。

編譯：Judith Cheng

（參考原文：5G Spectrum Needed, Says Expert，by Rick Merritt）

原文參考：

5G Spectrum Needed, Says Expert

US regulators need to open up licensing of millimeter wave bands to make way for a coming renaissance in wireless, according to a leading researcher.

Theodore Rappaport foresees networks using 28 to 90 GHz bands to deliver several Gbits/second to tomorrow's mobile devices. The wireless research center he runs at NYU Polytechnic is testing out such ideas, but a broader effort is needed, he said.

"We need a playground for carriers to develop the prototypes to show what can be done at 28, 38 and 70-90 GHz bands," Rappaport said in an interview with EE Times. "There's a big movement here, but I'm just afraid the US is behind in it," he said.

The Federal Communications Commission needs to license the bands for experimental and light commercial use on mobile apps, he said. "Korea and China see this opportunity and appear to be more spectrum friendly in the use of millimeter waves for cellular mobility," he added.

The 802.11ad standard for 60 GHz wireless LANs planted seeds here. But tomorrow's 5G cellular networks, now in development, could show a flowering of the spectrum, Rappaport believes.

5G "will be the first technology to use smart antennas -- hundreds of tiny antenna elements the size of a human freckle made in high-dielectric materials, phased together and sprinkled into smartphones," he said. "Phased arrays have been used in high-cost military systems, but we face a lot of technical issues bringing them to consumer products."

At the other end of the network, 5G will require new kinds of wireless routers and repeaters. This will provide intelligence for networks in which base stations collaborate to provide broadband links by quickly combining beams over distances of 200 to 400 meters, he said.

Rappaport's center has already created a database of the propagation characteristics of millimeter wave signals in urban New York. The work has attracted interest from corporate sponsors such as AT&T, Intel, Qualcomm, and Samsung.

"Our work showed directional antennas bouncing energy in an urban environment makes a good cellular link -- better than today's cellphones" in some respects, he said, pointing to a widely cited paper.

Going forward the center aims to develop statistical models and channel emulators to benchmark 5G systems and standards. The tools could help service providers develop cost estimates and plans for city-wide networks that ride millimeter waves.

Rappaport's NYU research center created a database of measured millimeter-wave propagation effects in New York's urban canyons.

—Rick Merritt, Silicon Valley Bureau Chief, EE Times