Jonathan Miller CERMUSA December 23, 2004 The W’s of WiMAX: What is it? When does it debut? Why use it? WiMAX is a new standard of wireless technology scheduled to debut in the second quarter of 2005. Technically termed 802.16 by the Institute for Electrical and Electronics Engineers (IEEE), WiMAX is intended to serve as a last-mile broadband provider. The entire 802.16 standard is divided into several smaller standards, each of which is intended to promote the three tenants of WiMAX: “standards-based, interoperable, and carrier-class” (Resnick).

Standardization and Interoperability WiMAX is less of a technological breakthrough than it is a successor to the popular but flawed Wi-Fi standard, which is used primarily to create “hotspots” in specific areas. (Hotspots are physical locations offering wireless internet access to patrons with Wi-Fi-enabled devices.) Wi-Fi is flawed because it was not designed with interoperability in mind. Consequently, devices produced by different manufactures are not guaranteed to work together properly. WiMAX, however, has been designed from its inception to overcome Wi-Fi’s caveats by instituting various standards and system profiles that will ensure compatibility among products from different companies. The IEEE-born WiMAX Forum, a consortium composed of over 150 member companies was established. According to WiMAX Forum president Ron Resnick (also director of Intel’s broadband wireless division), this forum “will conduct testing and label vendor systems ‘WiMAX Forum Certified,’ guaranteeing that products have been independently verified to be both conformant to the standard and interoperable with other vendor equipment.” The WiMAX standard consists of three primary versions: 802.16, 802.16a/d, and 802.16e. The first and most mature version, though the most mundane of the three, is 802.16. Operating in the 10 to 66 GHz spectrum, this version requires a line-of-sight, fixed position for

Miller 2 functionality. The likely cell radius (the estimated maximum distance that a usable wireless signal carries through the atmosphere) is one to three miles. (It is important to note that this distance, though regrettably short compared to the distances required to accommodate many rural, hard-to-reach locations, is a significant increase from the three hundred feet maximum required by the aging, though widespread 802.11 standard.) The 802.16 version supports bit rates ranging from 32 to 134 Mb/s at 28 MHz channelization and the channel bandwidths are 20, 25, and 28 MHz. The specification for 802.16a and 802.16d (collectively 802.16a/d) operates in the sub-11 GHz spectrum. Because of the use of such comparatively low frequencies, this version requires no line-of-sight and supports fixed and portable applications with a practical range of three to five miles. This range is termed practical because, though the utter maximum cell radius is estimated at thirty miles, several parameters, including tower height, antenna gain, and transmit power, not to mention atmospheric conditions, all contribute to the reach of the signal (or the lack thereof). It is possible to attain bit rates up to 75 Mb/s at 20 MHz channelization with 802.16a/d, and the channel bandwidths are selectable, though the channels must be between 1.25 and 20 MHz and have no more than 16 logical sub-channels. The third version of the WiMAX specification, the one that is most entirely in the “prenatal” stage, is 802.16e. Sporting attributes similar to .16a/d, .16e requires no line of site and supports the same channel bandwidths, though .16e’s spectrum is only below 6 MHz. Its bit rate tops out at 15 Mb/s at 5 MHz channelization and its cell radius is one to three miles, just like version 802.16. What makes 802.16e so special is its capability to support applications beyond fixed broadband; mobile broadband with regional roaming is achievable. This attribute may give .16e a cell phone-like quality, which is much anticipated by the many pro-WiMAX companies.

Miller 3 The breadth of the WiMAX standard helps it to achieve its goal of interoperability. WiFi is supported by WiMAX, which should help WiMAX gain a strong following among end consumers such as homeowners and storeowners, who have already shown strong interest in personal wireless setups (“free wireless internet at a gas station, anyone?”). However, before end users will ever see WiMAX, internet carriers and broadband service providers must first support the new standard. This is explained more thoroughly under “Timeline,” page 4.

Throughput, scalability, and coverage A single WiMAX 802.16a/d transmitter/receiver radio pair can provide shared data rates up to 75 Mbps, which is faster than traditional cable and Digital Subscriber Line (DSL) and comparable to T1 connectivity. Supposedly, “a single ‘sector’ [transmit/receive radio pair] of an 802.16a base station . . . provides sufficient bandwidth to simultaneously support more than 60 businesses with T1-level connectivity and hundreds of homes with DSL-rate connectivity, using 20 MHz of channel bandwidth” (Intel 3). These consumer figures appear to be based on a metropolitan setting, so the number of wirelessly-connected homes and businesses can be expected to decrease significantly in a rural setting, especially when the physical range of the 802.16a/d/e standard is considered (one to five miles on average). This is not to suggest that WiMAX could never serve as a rural broadband solution, however. The standard may be a very effective last-mile fix. (Note: “last-mile” is broadband-industry jargon referring to the considerable number of potential consumers who are “out of reach,” whether physically or in some other form, of most types of broadband.) Wireless communications obviously alleviates the need to lay and install expensive ground wire. WiMAX can cover areas that the cable and phone companies can’t – or won’t – go, and WiMAX can

Miller 4 provide such coverage relatively cheaply because of its compatibility with existing 802.11 and Wi-Fi networks. As may already be apparent, the robust 802.16 standard is quite scaleable. Whether it is handling data as a backbone of a dense metropolitan area network or satiating the broadband demands of rural consumers, WiMAX is touted to perform quite well in diverse applications.

Timeline and projected “battle plan” for success In the first quarter of 2005, the first products touting “WiMAX Forum Certified” labels will debut. Wireless Internet Service Providers (WISPs) will likely be the first buyers of the technology. The vice president of marketing at SR Telecom and a technical director of the forum, Stephane Cohen says, “[WISPs are] ready to deploy anything that will evolve to WiMAX certification because they feel it gives them a competitive advantage” (qtd. in O’Shea). Next to deploy will likely be international carriers and licensed competitive local exchange carriers (CLEC) (local phone companies). Cohen says larger carriers could take longer to deploy, perhaps in 2006, because they take new products in-house and perform numerous tests and benchmarks before giving the go-ahead for deployment. (O’Shea) The size of these deployments is what will most affect WiMAX’s progression. Detractors of the technology predict that the product certification process will take longer than expected, that service providers who originally agreed to utilize WiMAX products will change their ideas, and that the technology may have limited potential and only be useful as a gap-filler in carrier networks. Proponents of WiMAX disagree, believing that the technology’s ease of installation, affordability, and interoperability will prove WiMAX very successful. Critics believe that the 802.16e standard, debuting in late 2006 or 2007, will be a key benefit to wired

Miller 5 telephone companies, who could use the mobile capacity to gain some foothold on their wireless carrier competition. In 2007, it is expected that WiMAX will be built into 3G phones, along with Wi-Fi. (O’Shea) Much of WiMAX’s success does not rely on just the United States’ adoption of the standard; WiMAX’s creators see a huge market all over the globe. Perhaps because of this potential market, WiMAX has been engineered to interoperate seamlessly with its European equivalent, HIPERMAN. Much of the “US versus World” market debate arises from the difference of licensed and unlicensed frequency bands. Basically, licensed bands are better for communication because there is less noise at that frequency; however, licensed bands cost money. The US is in a situation in which mostly the unlicensed bands are initially open for WiMAX use, whereas in the international market, licensed bands are ready to include the technology. Additionally, because of the saturation of the United States with DSL and cable broadband, the WiMAX market is not expected to be as large in the US as in Western Europe, China, India, and Russia.

Summary WiMAX, the next generation of wireless broadband, is ready to debut to an international scene. Of the key factors that will affect the technology in the next several years, two of the most important are: the size of large carriers’ deployments and the viability of standardized, interoperable products.

Miller 6 Bibliography O’Shea, Dan. “A Standard Argument: Why WiMAX Will Rule” Telephony’s Complete Guide to WiMAX. 31 May 2004. Resnick, Ron. “The WiMAX Bridge to Broadband” Telephony’s Complete Guide to WiMAX. 31 May 2004. Intel. “IEEE 802.16 and WiMAX” Intel Corporation. 2003