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Overview The latest technology buzz is WiMAX wireless networks. We have heard numerous things in regards to this terrifi new long haul wireless technology that it almost seems as even though you are just a phone call away from having yours’ designed and installed. Well before you commence assuming things like we all do, we thought as engineers and network architects we would percentage personal experiences and the experiences of colleagues from around the world, in a manner that is direct, helpful, educational, and surely reality based. This is a backpocket Primer for anybody now dealing with the implementation of a WiMAX network. First, there are various incorrect conceptions surrounding WiMAX that need to be cleared up so that the business distinct features and engineering basis have a mutual understanding. Secondly, the persons who make the respective conclusions within your organizations need to comprehend that there are deviations amongst a private network and an interoperable network strategy. This subtle divergence does subsist and requires a plan which considers the final transition aspects, if considered now, to without apparent effort provide a lower cost upgrade to a true interoperable network, now incorporating diverse vendor equipment. Finally, while WiMAX has been out globally for various years, it is very new to the United States, only a few months old, with very little training and education available to those who have the obligation to build these systems or those who will make the financial and technical conclusions to have these schemes built for them as part of their long haul wireless strategy. Our experiences and the experiences of our collegues are offered here as contributions as well as tying these in to the standards and corroboration authorities all meant to provide a reality based quick reference education for anybody in the throws of How to Build a WiMAX network. Primer WiMAX is a popular designed for fixed broadband wireless access featuring a controlling base station, that connects subscriber stations not to each other but to respective public networks, such as the Internet, linked to that base station. The acronym means ” international interoperability for microwave access” or (WiMAX). WiMAX, as a standards initiative, is based on a “set of profiles” supporting a wide range of frequencies (up to 66GHz)with channel sizes (1.25MHz to 20MHz) and apps (LOS and NLOS), and at long last PTP and PTMP. The WiMAX profiles narrow the scope of 802.16 to focus on introductory service specific configurations. The IEEE titled the specification 802.16 and freed it December 2002. The profiles addressed in that “profiles release” are 802.16-2004 (old d) and 802.16e as staged further down. The WIMAX forum was formed eight months earlier in April 2002 to support, promote and certify compatibility and interoperability of gimmicks based on the 802.16 specification, and to develop such gimmicks for the marketplace. Founding Members of the institution include Airspan, Alvarion, Analog Devices, Aperto Networks, Ensemble Communications, Fujitsu, Intel, Nokia, OFDM Forum, Proxim, and Wi-LAN. WiMAX is the IEEE 802.16 Point-to-Multipoint broadband wireless access frequent for systems in the stated frequency ranges. WiMAX will initially provide fixed nomadic, portable and eventually, mobile wireless broadband connectivity. To that end there are two standards (802.16d (new -2004) and 802.16e respectively) even though they will both carry out similar functions because they must be interoperable. One distinctly is a fixed solution and the other a mobile solution that ought to still commune with a fixed solution. So one of the primary considerations is whether you want to build out a mobile or fixed network. In a great deal of cases you would have already considered your target market segments, spectrum availability, regulatory constraints and your deployment need. Which One do I Need? Generally speaking, the current 802.16-2004 (originally 802.16d) fixed network productions are less complex than 802.16e mobile network schemes because; they may be used in a wider range of unlicensed bands, they offer a more quickly time-to-market, and in a great deal of cases a higher throughput than 802.16e equipment. On the other hand, there is better help for mobility and a wider range of terminal form constituents vantages of 802.16e equipment. It’s surely a considerateness but no matter what you chose the migration paths to move in either direction are without apparent effort achieved through overlay networks, software upgradeable base stations, dual mode appliances and dual mode base stations. This contemplation assures you are not stuck in one mode or the wrong mode and that your basi investment is protected. Makes the CTO and CEO happy. WiMAX base stations transmit up to 30 miles, but because it is a cell-based topology, would yield a more typical range of 3 to 5 miles. WiMAX schemes may deliver a capacity of up to 75 Mbps per channel, for fixed and portable access applications. This is sufficient bandwidth to simultaneously help hundreds of businesses with T-1 speed connectivity and thousands of residences with DSL speed connectivity as we have seen. WiMAX technology will be integrated in portable computers and PDAs expected in late 2006 and early 2007, permitting for urban areas and cities to become “MetroZones”, the new buzz word, for portable outdoor broadband wireless access. In addition, Wireless service suppliers and telecommunication instrumentation industries are embracing WiMAX technology because of it is vast cost vantages to provide that last-mile connectivity to huge elements of the world that are too costly to serve with wired technologies calling for all that trenching. Security Due to the security issues with WEP in the 802.11 Wi-Fi arenas, the standards bodies took no prospects with WiMAX, and wisely prioritized security from the onset. Base station designers went to work to make sure a devoted high performance security processor. The WiMAX security general requires that all traffic be encrypted with CCMP (which is Counter Mode with Cipher Block Chaining Message Authentication Code Protocol). According to the WiMAX forum, the group’s aim is for end-to-end authentication. WiMAX uses PKM-EAP (Extensible Authentication Protocol), which relies on the TLS standard following public key cryptography. Having addressed this level of security from the commence provides an splendid reference point to add multi-level security choices as well, if your implementation requires an MLS approach. Secure (blacker) implementations would require such an approach. What is Released? The primary certification release for 802.16-2004 fixed is out there already and includes merchandise from certified venders with two profiles in the 3.5GHz and the 5.8GHz bands supporting fixed and nomadic access. The profiles for 802.16e mobile are not available nor freed as of this writing but are expected to be in the ranges of 2.3GHz to 2.5GHz when officially released. WiMAX profiles based on 802.16-2004 are better suitable to fixed apps that use directional antennas because OFDM is inherent less complex than SOFDMA employed in the mobile application. As a results, 802.16-2004 networks will be deployed much more immediate and at a lower cost. Our experiences are with these freed systems in the US and around the world in ground applications, mobile military, public safety and maritime applications. Planning for WIMAX Companies, cities or projects in maritime or ground schemes in the US that have decisive to or are giving careful consideration to building and operating a WiMAX network will have a few primary issues to consider. The original spectrum for WiMAX in the USA is unlicensed spectrum in the 5GHz range. Given this spectrum is open it will have inherent interference issues and risks which will require attention. There are a heap of ways of overcoming interference issues. The answers come from a proper internetlocation selection, following your RF survey training and from the actual chosen equipment. So, the planning and internetlocation survey results stay the key to your convinced success. Summary WiMAX provides optimized solutions for fixed, nomadic, portable and mobile broadband wireless access. There are two flavors in respective release and implementation modes. The primary is 802.16-2004 WiMAX with two firstborn frequency profiles – the 3.5GHz and the 5.8GHz bands supporting fixed and nomadic access in LOS and NLOS environments now. The other flavor is 802.16e WiMAX with expected profiles in the 2.3GHz and 2.5GHz ranges optimized for dynamic mobile radio channels supporting hands-ff and roaming –arriving by 2007. Another stimulating engineering science for all of us. Have fun! |
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