無線網路應用的演進，從早期的純語音通訊逐漸演進到寬頻多媒體應用。隨著各式各樣的網路應用服務不斷地推陳出新，現有的3G無線通訊系統勢必無法滿足人們未來對網路頻寬的需求。有鑑於此，國際電信組織（International Telecommunication Union, ITU）訂定了IMT-Advanced規格，以作為4G無線寬頻網路的基準。為了搶佔4G無線通訊系統的市場，IEEE 802委員會成立了IEEE 802.16m任務小組，以IEEE 802.16e為基礎，發展符合IMT-Advanced規格的IEEE 802.16m系統，來推動WiMAX成為4G無線通訊系統的標準之一。

IEEE 802.16m支援高速寬頻應用

與現有3G系統比較，IEEE 802.16m對高速寬頻應用的支援，可以從提高傳輸速率以及增強對高速移動使用者的服務兩方面來觀察。在提高傳輸速率方面，IEEE 802.16m對靜止的用戶提供高達1Gbps的下載速率，而對於移動中的使用者，也提供最高100Mbps的下載速率，這樣的傳輸速率用來支援目前常用的即時影音服務（例如網路電視與影像電話）已綽綽有餘；另一方面，IEEE 802.16m對高速移動使用者的支援，則允許使用者的移動速度可高達時速350公里，如此一來，使用者即使搭乘高速鐵路，仍然能夠享受到IEEE 802.16m的網路服務，不需要擔心斷訊的問題。

資策會與國際大廠的合作

IEEE 802.16m技術涵蓋範圍廣泛，各家廠商在參加標準制定會議時，彼此的關係是競爭還是合作，在不同技術議題上，可能會有不同的局面。兩家廠商會在某些議題上因為彼此理念相近而互相合作；同時也在其他議題方面因為彼此的技術互不相容而採取抵制的態度。目前資策會與國際大廠合作的議題有：

Relay：ETRI、Fujitsu、Intel、NSN、Nortel、

Samsung

Link budget：Intel、Motorola、Samsung

Frame structure：Fujitsu、Intel、LG、Nortel

Addressing：Intel、LG、Nortel、NSN、Samsung

Power control：ETRI、LG

Power management：NSN

結語

IEEE 802.16m是4G無線通訊網路的熱門技術，國際資通大廠均積極投入IEEE 802.16m標準的制訂，以便在4G通訊市場取得優勢。過去資策會在IEEE 802.16j的標準制定工作上交出了漂亮的成績單，現階段資策會在IEEE 802.16m方面扮演的角色，則是持續參加IEEE 802.16m標準制定會議、協助國內產學界推展我國的技術研究成果進入IEEE 802.16m標準、並且與各家國際大廠接觸，尋求未來開發與測試的合作機會，以厚植國內產學界在IEEE 802.16m的相關產品與技術上的研發能量。

(本文作者為網路多媒體研究所WiMAX技術中心正工程師許俊彥，e-mail: hcy@iii.org.tw)

Wireless networking applications have seen a gradual evolution from voice-only communications in the early days to today’s broadband multimedia applications. With new types of mobile application service appearing all the time, existing 3G (Third Generation Mobile Communications) mobile networks will increasingly be unable to meet people’s broadband wireless access needs. Having observed this trend, the ITU (International Telecommunication Union) has formulated the IMTAdvanced specification to serve as the foundation for 4G (Fourth Generation Mobile Communications) mobile broadband network. The IEEE 802 Committee established the IEEE 802.16m working group to develop the IEEE 802.16m system, an IMT-Advanced compliant standard based on IEEE 802.16e, to facilitate WiMAX as one of the major 4G mobile communications standards.

IEEE 802.16m Supports High-speed Broadband Applications

Compared with existing 3G systems, the IEEE 802.16m system has significant enhancements for wireless access data rate and high-speed mobility support. For stationary users, the IEEE 802.16m system supports a downlink data rate of 1 Gbps.For moving users, a downlinke data rate of up to 100 Mbps is available. The high data rate enables the IEEE 802.16m system more than adequate to support today’s most commonly used audiovisual services (such as mobile TV and video-calls). The IEEE 802.16m system can support users with a moving speed of up to 350 km/h, this ensures service continuity for users even when they are traveling on a high-speed rail.

Collaboration between the Institute for Information Industry and Leading International Vendors

IEEE 802.16m adopts a wide range of top technologies and thus various companies participating in the f o r m u l a t i o n o f t h i s s t a n d a r d . A c o m p a n y m a y collaborate, or compete, with one another over various technical issues according to their positions on this technical issue. Two companies may collaborate with each other over some issue because they have similar positions but against each other over another issue because their solutions are not compatible. The aspects of IEEE 802.16m technology in which the Institute for Information Industry is currently collaborating with leading international vendors include:

Relay: ETRI, Fujitsu, Intel, NSN, Nortel, Samsung

Link budget: Intel, Motorola, Samsung

Frame structure: Fujitsu, Intel, LG, Nortel

Addressing: Intel, LG, Nortel, NSN, Samsung

Power control: ETRI, LG

Power management: NSN

Conclusions

IEEE 802.16m is a promising 4G mobile wireless communications technology. Leading international ICT vendors are participating actively in the formulation of the IEEE 802.16m standard to ensure their advantage in future 4G mobile communications market. Having achieved impressive results in its involvement in the formulation of the IEEE 802.16j standard, the Institute for Information Industry is now participating in the development of the IEEE 802.16m standard, facilitating Taiwan industry and universities to have their technology development achievements incorporated into the IEEE 802.16m standard. By liaising with leading international vendors, the Institute is able to identify future opportunities for collaboration on technology development and testing, which in turn will strengthen Taiwan’s R&D capabilities with respect to IEEE 802.16m compliant products and technologies.

(Hsu, Chun-Yen is a Senior Engineer at the WiMAX Technology Center, Networks and Multimedia Institute, Institute for Information Industry; e-mail: hcy@iii.org.tw)