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What is WiMax? Defined by the WiMax forum as Worldwide Interoperability for Microwave Access, WiMax is a “standard-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL”. The WiMax Forum, formed in 2001 to promote performance and interoperability of the standard Institute for Electrical and Electronics Engineers (IEEE 802.16), is the exclusive organization committed to certifying the interoperability of BWA products. It describes and conducts conformance and interoperability testing achiever the “WiMax Forum Certified” designation and exhibits this mark on the products and marketing materials. The WiMax, however in essence, is a standard initiative its purpose is to ensure that the broadband wireless radios manufactured for customer use interoperate from vendor to vendor. The Idea of WiMax Much of the credit for the formation of the “WiMax Forum" and the notion of the WiMax initiative must go the founding members of the Forum, which committed themselves early to the process of creating a collaborative standards body. Once Intel came aboard, it acknowledged that for the broadband wireless industry (both fixed and mobile broadband wireless) to gain transaction and wide acceptance both hardware prices must decrease and a consistent operating environment must be cemented into place. The launch, however, had to begin with the silicon chip manufacturers whose chips products would form the core of the WiMax technology value and capability. Intel deserves as great deal of credit for helping drive this process. Other technology standards for Digital Subscriber Line (DSL) service and the Cable Broadband industry (the DOCSIS standard) have been responsible for driving those respective technologies to wide acceptance. WiMax itself is commonly mentioned in conjunction with the Institute for IEEE 802.16 working group, which is authorized with characterizing the technological aspects and features that will be incorporated into WiMax. Advent of WiMax WiMax is a new term of a standard initiative--and in particular the launch of numerous WiMax technology supporting chipset by forum members. However, much of the technology set is existent in industry today. A number of best of bread broadband radio manufacturers already offered various elements being incorporated into WiMax as proprietary technology, However vendors rarely offered consistent iterations of radio modulation and other techniques --ensuring that solutions had to single vendor specific. This is true on the fixed wireless side and even more so for unlicensed band fixed wireless. However mobile broadband wireless technologies suffered from the fragmentation of multiple proprietary approaches. This means that much of the technological capability of WiMax is relatively mature. Truth is, radio vendors who are members of the forum have deployed equipment in over 125 nations around the globe. The
combinations of these advanced technologies into two standards packages for
Fixed and Advantages of WiMax Based on a forward-looking core set of technology, WiMax is a structure for wireless development. 3GPP cellular's 4G, 802.22 Cognitive Radio RAN (Rural Area Network), and 802.20, the High Speed Mobile Broadband Wireless Access (MBWA) Working Group, have more recently have shifted toward use of similar constructs of multi-channel scalable OFDM, HARQ, FEC, MIMO-AAS and other complementary technologies as are part of WiMAX. WiMax is selected as the metropolitan area network (MAN) technology that can connect IEEE 802.11 (Wi-Fi) hotspots with each other and to other parts of the Internet and also provide a wireless alternative to cable and DSL for last mile (last km) broadband access. Moreover, the field of uses is broader and overlaps those for mobile WAN (wide area networks) and WLANs. IEEE 802.16 provides up to 50 km (31 miles) of linear service area range and allows connectivity between users without a direct line of sight. Note that this should not be taken to mean that users 50 km (31 miles) away without line of sight will have connectivity. Practical limits from real world tests seem to be around "3 to 5 miles" (5 to 8 kilometers). The technology has been claimed to provide shared data rates up to 70 Mbit/s, which, according to WiMax proponents, is enough bandwidth to simultaneously support more than 60 businesses with T1-type connectivity and well over a thousand homes at 1Mbit/s DSL-level connectivity. Real world tests, however, show practical maximum data rates between 500kbit/s and 2 Mbit/s, depending on conditions at a given site. It is also anticipated that WiMax will allow inter-penetration for broadband service provision of VoIP, video, and Internet access—simultaneously. Most cable and traditional telephone companies are closely examining or actively trial-testing the potential of WiMax for "last mile" connectivity. This should end in better price-points for both home and business customers as competition results from the abolition of the "captive" customer bases both telephone and cable networks traditionally enjoyed. Even in areas without preexisting physical cable or telephone networks, WiMax could allow access between anyone within range of each other. Home units the size of a paperback book that provide both phone and network connection points are already available and easy to install. The potential interoperability of WiMax with legacy cellular networks is interesting. WiMax antennas can "share" a cell tower without compromising the function of cellular arrays already in place. Companies that already lease cell sites in widespread service areas have a unique opportunity to diversify, and often already have the necessary spectrum available to them (i.e. they own the licenses for radio frequencies important to increased speed and/or range of a WiMax connection). WiMax antennae may be even connected to an Internet backbone via either a light fiber optics cable or a directional microwave link. WiMax is measured by some cellular companies as a means of intensifying bandwidth for a diversity of data-intensive applications. In line with these possible applications is the technology's capacity to operate as a very high bandwidth "back-haul" for Internet or cellular phone traffic from remote areas back to a backbone. WiMax is definitely not limited to remote applications, and may be in fact an answer to expensive urban deployments of T1 back-hauls as well, in spite of higher cost-effectiveness of WiMax in such applications. Given developing countries' (such as in Africa) limited wired infrastructure, the costs to install a WiMax station in conjunction with an existing cellular tower or even as a solitary hub will be diminutive in comparison to developing a wired solution. The wide, flat expanses and low population density of such an area lends itself well to WiMax and its current diametrical range of 30 miles. For countries that have skipped wired infrastructure as a result of inhibitive costs and unsympathetic geography, WiMax can enhance wireless infrastructure in an inexpensive, decentralized, deployment-friendly and effective manner. Spectrum Provisions for WiMax The 802.16 specification applies
across a wide swath of RF spectrum, but specification is not the same as
permission to use. There is no uniform global licensed spectrum for WiMax. The
biggest segment available in the There is some prospect that some of a 700MHz band might be made available for WiMax use, but it is currently assigned to the analog TV and awaits the complete rollout of HD digital TV before it can become available, likely by 2009. Moreover, there will be other uses suggested for that spectrum if and when it actually becomes open. It seems likely that there will be several variants of 802.16, depending on local regulatory conditions and thus on which spectrum is used. Even if everything but the underlying radio frequencies is the same. WiMax equipment will not, therefore, be as portable as it might have been. And perhaps even less so than WiFi, whose assigned channels in unlicensed spectrum varies more than a little from jurisdiction to jurisdiction. WiMax Security There is a historical body of evidence supporting the safety of technologies used in upcoming WiMax products. Microwave and other spectrum technologies enjoy over a hundred years of historical evidence of safety when prudently handled and configured. The amount of power allowed to deliver broadband wireless signal varies from frequency to frequency, however most are modest topping out around 40 watts at the tower. While certain basic precautions need to be taken when onsite at communications towers (i.e. standing redirectly in front of active microwave links at essential zero range) the configurations for public use are understood and safe. Customer premise equipment is even safer. With the sprint of WiMax vendors achieving initial certification those products, which in most cases have been shipping for some time, actually have an operational history of safety. Importance of WiMax One must comprehend the present state of technical fragmentation of the fixed broadband wireless industry to understand the importance of WiMax. Early broadband wireless systems began as expansion of indoor local area network (LAN) technology known as Wi-Fi or the 802.11b protocol. This standard has evolved into a ubiquitous and widely available standard used in short range hotspots all over the globe. However, the media access controller (MAC) and physical layer (PHY) specifications for this protocol are suboptimum for outdoor citywide wireless networks or metropolitan area networks (MAN). Recent updates and new standards such as 802.11g and 802.11a have improved these elements. However, once again these technologies are organized forgreatest performance in small venues and at short range. Recent developments should be noted in the ratification standard of the IEEE 802.11n protocol offer the promise of significant improvements to Wi-Fi --progress that will blur the lines of capability between WLAN and more robust WMAN (wireless metropolitan area network) systems somewhat. While 802.11n is not importantly optimized for great range, its bandwidth capabilities will be a major leap ahead from Wi-Fi. Its range improvements in the hotspot will be significant also. Previously, this standard was mired in the detritus of two competing approaches that appear to have been largely resolved. To compensate up until now vendors developed proprietary MAC and PHY layers based on the root LAN standard of 802.11. Many of these systems are in use today and possess significant improvements in modulation scheme, polling technology and data transport that enable effective and modestly affordably citywide or rural wireless networks. The force to manufacture their own silicon chips to convey improvements, significantly slowed radio vendors’ adoption of broadband fixed wireless versus cheaper mass market technologies such as DSL and Cable modem service. The standards for broadband wireless delivery in the mobile field are less disjointed. Importantly moreover, the cost, speeds delivered and time to market of broadband mobile solutions have been suboptimum. The guarantee of 3G services has been slow to emerge. And while that is shifting with wide deployments coming from Verizon using its EVDO system as well as from Sprint and Cingular, mobile WiMAX systems based on newer technology such as OFDMA® offer the guarantee of cheaper, more effective and faster deployments of broadband mobile wireless systems. Links: Business VoIP About the Author: Katrina Marie Coyoca, is staff writer for VoIP Architecture, a one-stop information resource about Voice over Internet Protocol (VoIP). The views and opinions expressed in this article do not necessarily represent the views of MobileIN.com. You are encouraged to seek the advice of health professional concerning these matters of great importance.
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