<font color=Black>w<font color=Red>i<font color=Black>max: <font color=Red>The 3G challenger
<font color=Black>2003-6-9 11:23:51
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Even as 3G grapples with issues of cost and actual market demand, another international wireless data standard is threatening to upset its position. The WiMAX alliance''s 802.16 specification enables almost 50km in range and peak shared data rates of 70Mbps.
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By Lee Ser Wei
Wireless intra-networking is finally mature with 802.11 and fast enough to be usable, yet how does a workgroup go beyond itself, and talk to the outside world of the Internet? WiFi and its brethren are ideal for ad hoc networking, and with many highly-mobile applications from gaming to military, the idea of outdoor and free-roaming workgroups are finally possible. Field applications are no longer restrained by slow, proprietary (expensive) or purely line-of-sight devices.
However, WLANs (wireless local area networks) are themselves tethered to a hotspot running on any of the 802.11 flavours, and would be pretty hard-pressed to connect to anything other than the people in the vicinity. Current solutions could be to attempt a GPRS (general packet radio service) connection over the cellular phone network. Of course, this is both slow and exorbitantly expensive. And the solution requires a base station to be in range as well.
3G, the high-bandwidth cellular voice-cum-data technologies such as WCDMA (wideband code division multiple access), is still facing deployment issues, mainly due to cost and actual market demand. StarHub for example cited insufficient demand for it and had been asking for the 3G deployment deadline in 2004 to be removed. Meanwhile, another international wireless data standard is threatening to upset 3G''s position.
Entering the fray is WiMAX, Worldwide Interoperability for Microwave Access. The WiMAX alliance is behind the IEEE 802.16 specification. The standard, which was first published on 8 April 2002, was created in a two-year, open-consensus process modelled after the successful 802.11 workflow. Engineers from the world''s leading operators and vendors came together to define the standard in a coherent manner. The companies include Airspan Networks, Alvarion, Aperto Networks, Ensemble Communications, Fujitsu Microelectronics America, Intel, Nokia, Proxim, Samsung and Texas Instruments. They expect to start shipping products in the second half of 2004.
Recently IEEE approved the 802.16a and 16c amendments, adding on to last year''s 802.16 standard. The original specifications called for a frequency between 10GHz to 56GHz ¨C a band already licensed out in many parts of the world. The amendment covers the 2GHz to 11GHz frequency range for "a", making it suitable for connection to WiFi hotspots, and spectrum expansion of 10GHz to 66GHz in "c".
It is a wireless standard enabling almost 50km in range and peak shared data rates of 70Mbps. Positioned as a wireless, last-mile solution, it is to cover where DSL (digital subscriber line) and cable are not available or difficult to implement, like mountainous stretches of terrain for example. Cable systems today are based on the residential cable TV infrastructure, so they are usually unavailable in business districts, where the profitable corporate entities are. Meanwhile, DSL is a copper-based method that typically offers mid-range 128kbps to 1.5Mbps data services, but is not available to every subscriber because of distance limitations, that affect data speed, from the central hub or the local repeater.
WiMAX is also more scalable: carriers can expand them as subscriber demand for bandwidth grows by adding channels or cells like cellular equipment.
802.16a is considered the next logical stage beyond WiFi because it now targets both the wide-area and broadband aspects. 802.16a is still currently about static models. Going mobile in version "e", WiMAX intends to cater to the individual user.
It already includes most advances that are going into the 802.11 series, such as improved security, higher data rates, and better utilisation of the spectrum.
WiMAX president Margaret LaBrecque had said the alliance will target 802.16 products as a cost-effective alternative rivalling today''s broadband options: the 1.54Mbps T1 circuits used by enterprises and broadband cable services or DSL services for small businesses and residences. Wireless base station equipment would cost under $35,000, she said. Each base station will be capable of serving up to 60 enterprise T1 circuits, as well as a mix of residential and small business customers at lower speeds of 256kbps or 384kbps in DSL-type configurations, and would be ideal to tie together 802.11b WiFi hotspots as well.
LaBrecque also said that while an 802.11b card would not work directly in an 802.16 network, a router could bridge the two wireless systems.
The coming WiMAX picture suggests that the challenges of seamless roaming between the short-range WiFi hotspots, and their upcoming solutions from teamed efforts like Proxim, Motorola and Avaya''s, may actually be made irrelevant.
The mobile version of 802.16, branching as the 802.16e, could eventually rival 802.11b products. 802.16e is in development to add portability to stations that primarily support fixed wireless networking in the 2GHz to 6GHz bands.
But Dean Chang, who is the chairman of the IEEE 802.16e subcommittee and also director of product development at Aperto Networks, said that while he expects completion of the final specifications by the end of 2003, he declined to predict when 802.16e products would actually reach the market.
The Infocomm Development Authority of Singapore (IDA) recently concluded its Mobile Workforce Solutions Call For Collaboration, a pilot programme on deploying wireless applications into the mainstream workforce. The factors for attaining business competitiveness cited by IDA included cost savings through better productivity and efficiency, as well as increase operational management. WiMAX has several features that fit the bill, with several key advantages over landlines.
One of the most compelling aspects of broadband wireless access (BWA) technology is that high-bandwidth networks can be created quickly, set up in mere weeks by deploying a small number of base stations on buildings or poles to create high-capacity wireless access systems. There is no need to lay any physical connections like fibres or cables. Instead of the hotspot roaming, the WMAN (wireless metropolitan area network) that 802.16e allows may actually overtake WiFi in terms of takeup due to sheer convenience for users and savings on CPEs (customer-premises equipment). The upcoming mobile editions of VOIP (voice over Internet protocol) may actually take off as the coverage broaches that of the established 2G and above cellular networks.
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