I. Introduction To WiMAX Technology And Applications

The IEEE 802.16-2004 WiMAX technology provides wireless “last mile” broadband access in the Metropolitan Area Network (MAN) with performance comparable to or better than traditional DSL, Cable or DS1 (T1)/E1 leased line services. The term MAN as used here refers to radius of coverage, rather then to population density. In fact, WiMAX technology is being used both in rural and metropolitan/urban areas to provide fixed location, wireless broadband access (based on IEEE 802.16-2004). A later version of the WiMax standard (IEEE 802.16e) will be used for mobile broadband wireless access.

Up until recently, the fixed WiMAX applications have been focused on three primary areas:

Other potential uses of WiMAX technology include Cellular Backhaul (using WiMAX as an overlay network with IEEE 802.16-2004 based point-to-point links sharing the PMP infrastructure), and Public Safety Services and Private Networks (Support for nomadic services and the ability to provide ubiquitous coverage in a metropolitan area provides a tool for law enforcement, fire protection and other public safety organizations enabling them to maintain critical communications under a variety of adverse conditions). At the WCA Symposium, there were talks from Disney and AOL of using of fixed WiMAX technology (IEEE 802.16-2004) to deliver “last mile” broadband video content.

II. WiMAX (IEEE 802.16-2004) For Fixed Access To Large Grid Computing Sites

A new application of WiMAX is now just emerging — one that has great potential for use in providing broadband access to Grid computer sites. AT&T and other long distance carriers have been interested in using WiMAX to extend their long haul private line and broadband data networks (e.g. n x DS1, Frame Relay, IP-VPN, Ethernet/ VLANs) to business customers. In doing so, the long distance carriers would save considerably on the access charges they would need to pay to local exchange carriers that connected to their networks. They would also reap considerable savings on operating expenses (OPEX) that they would otherwise pay for dedicated wired access lines and equipment (e.g. repeaters, remote terminals and central office terminals).

In the WCA Symposium talk on Broadband Wireless Access, “Why AT&T Joined The WiMAX Forum,” N. K. Shankaranarayanan (Shanker), Senior technical specialist for access technology and applications research at AT&T Labs-Research, documented the cost savings in access charges that AT&T might realize through fixed broadband wireless access. As the largest CLEC in the United States, AT&T has direct fiber optic connections to the largest business customers, with DS1 leased line connections to smaller locations. Shanker stated that AT&T could save billions of dollars on the access charges it currently pays to LECs and in the associated access network OPEX. Noting that dedicated access and data services are growing market segments, he opined that: “WiMAX addresses the sweet spot for dedicated broadband access.”

That is: 0-3 miles, 1 — 4 DS1's (up to about 6 Mbps), needed by many small to medium size business customers. AT&T will be conducting WiMAX based, broadband wireless trials in 2005. Shanker hinted that AT&T would extend their broadband IP network with last mile broadband wireless access. One could then expect an IP-VPN service to be delivered over WiMAX.

In another WCA Symposium session, Mick Reeve, group technology officer of BT Group, explained the important role that broadband wireless will play in their 21st Century Network. GRIDtoday previously reported that the 21CN would be used as the infrastructure for BT's managed Grid interconnection service. Please refer to www.gridtoday.com/04/1011/103940.html.

Global harmonization of wireless and wire-line networks is a major goal for BT. Reeve stated that the the 21 CN's standards based architecture allows BT to effectively integrate a wide range of wire-line and wireless broadband technologies, including fixed, nomadic and mobile/ roaming. BT would like broadband wireless initiatives and developments to merge into the NGN architecture efforts that are ongoing in the ITU-T, ATIS and ETSI. Please refer to the recent GRIDtoday article on NGNs: In Search of the Next Generation Network at www.gridtoday.com/05/0117/104474.html.

Reeve noted that the IEEE 802.16 WiMAX standards effort was restricted to MAC and PHYs. Other functionality and hooks are needed for the systems aspects: QoS and CoS, radio reporting, smart antennas, interfacing to rest of network, OSS's, etc. BT is keenly interested in the mobile version of WiMAX- IEEE 802.16e — to match with their vision of mobile access to the 21CN. Many other telecom carriers (telcos) have joined the WiMAX Forum. Besides AT&T and BT, these include: Deutsche Telecom, France Telecom, Portugal Telecom, Altitude, Qwest, SBC, Covad, Sprint, Nextel, XO Communications, Reliance Telecom and others. There is an active Service Provider WG there. That WG has prioritized optional features in IEEE 802.16-2004 and has just completed a survey of WiMAX system requirements, which will be used to guide the development for WiMAX certified products. Please refer to: www.wimaxforum.org/news/press_releases/WiMAX_ServiceProviderAnnouncemen t_FINAL.pdf.

III. Summary And Conclusions

The WiMAX fixed broadband wireless technology could provide a very cost effective means for smaller computing centers to access larger Grid computing sites, over a long distance network. In particular, if the access bandwidth required is on the order of 1.5M bps to 10 Mbps, the fixed version of WiMAX (IEEE 802.16-2004) technology could be used to provide the following network services:

The telco providing WiMAX last mile access, could offer the above services as customer administered or as a managed service to interconnect Grid computer sites.

A future version of WiMAX (IEEE 802.16e) might be cost effective in providing notebook PC or PDA based, mobile access to Grid sites or corporate data centers. However, IEEE 802.16e has not been standardized yet and will face competition from a variety of 3G — like mobile broadband technologies, as well as IEEE 802.20.

About Alan J. Weissberger

Alan J. Weissberger is actively seeking clients in need of his expertise in the telecommunications field. If you would like to speak personally with Alan about how he could help your company, feel free to contact him via e-mail at [email protected] or [email protected]. To learn more about his extensive qualifications, read his annotated biography below.

As the founder and Technical Director of Data Communications Technology (DCT), a technical consulting firm started in March 1983, Alan J. Weissberger specializes in telecommunications standards and their implementation. His clients have included network providers (AT&T, NTT, Pacific Bell, US West, Entel and CTC in Chile, Telkom South Africa, Moroccan PTT, others), equipment and semiconductor manufacturers, and large end users. In 1995 and 1996 Alan was the principal architect for the European Commission's multi-service, multi-country ATM network — the largest private network in Europe (that network has now evolved into Gig Ethernet over CWDM). In 2000-01, he was Ciena's lead ITU-T delegate, contributing to the standardization of the optical control plane in SG13 and SG15. Alan now represents NEC Corp in several OASIS TCs dealing with Web Services, while also attending the Global Grid Forum and the Optical Internetworking Forum (OIF).

To read his entire biography, please visit www.gridtoday.com/04/1011/bio.html.