Light Reading says the upcoming edition of Unstrung Insider notes that the two WiMax specifications (802.16-2004 and 802.16e), were originally supposed to be backwards compatible. But they’re not.
802.16 Task Group E (802.16e) is charged with developing an amendment to the current 80.16-2004 standard that covers ‘Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands.’
“This implies 802.16e would be used for both fixed and mobile access and according to several sources, dual fixed-mobile operation is still the goal,” writes the report’s author, Gabriel Brown, chief analyst for the Unstrung Insider.
But it’s an open secret in the industry that the mobile specification will not initially interoperate with the fixed WiMax products.The mobile standard will implement a new physical (PHY) layer on the chipset and enhancements to the media access control (MAC) to make it more suitable for mobile applications. “In effect then, there will be two types of incompatible WiMax one that s been widely implemented today for fixed use, and another that is still in draft form for mobile/portable,” writes Brown.
Chipmaker Intel, one of the leading proponents of mobile WiMax, confirms that the two specifications will not work together.
“Yes, that’s exactly right, they do use different PHYs,” an Intel spokeswoman tells Unstrung. She describes the two specs as “separate but complimentary,” saying that Intel envisages fixed WiMax being used as a system to backhaul data for mobile WiMax, when 802.16e products become available.
And Brown notes that there may be some move towards backwards compatibility in the future:
“Sources say that… both sets of specifications may be consolidated into one ber-standard document that will likely be known as 802.16-2005. They say this could happen at the next IEEE meeting in July 2005. Other sources also say there is a slim, outside chance that a mode that is backward compatible with 802.16-2004 could be introduced to the 802.16e specifications at the last minute this is considered unlikely, however.”
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A Scalable OFDM carrier is the next frontier for Mobile WiMax, but it “breaks” compatibilty with 802.16-2004. Moving to mobilized WiMax (and S-COFDM) will not be the smooth transition everyone was hoping for. Plain vanilla 802.16-2004 isn’t compatible with the new Mobile WiMax/WiBro standard. That’s forcing chip companies to create “enhanced” 802.16-2004 WiMax chips, with a foot in each camp. Two mobile standards (IEEE 802.16e & WiBro) agreed to merge to avoid political, technical and economic headaches. Intel wanted the Scalable COFDM technology while South Korea wanted early entree into the WiMax market. Intel and LG are now working together to bring Korea’s 2.3 GHz WiBro system to the United States. And elements of WiBro, specifically scalable COFDM, are being incorporated into Intel chips. Samsung and LG Electronics lead the world in WiBro – and may have first mover advantage in Mobile WiMax. Intel could not afford to loose China. Lost in translation may be IEEE 802.20 and the original IEEE 802.16-2004 standard. The mobilized IEEE 802.20 “standard” now appears to offer few advantages over the WiBro/WiMax “e” juggernaut. Cellular support is tepid as EV-DO and HSPDA loom. Flarion is promoting their FLASH-OFDM system as the “defacto” standard. Meanwhile, “enhanced” WiMax chips, with the ability to interoperate with Scalable COFDM (for better range), may mean the plain vanilla 802.16-2004 standard could be quickly obsolete.
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Among the reports key findings:
- The first Mobile WiMax services will launch in Korea in mid 2006, using Samsung equipment; U.S. service launches will follow, possibly as soon as 2007.
- Stealth chipset startups are attempting to leapfrog the market and go directly to Mobile WiMax (802.16e); names in the frame include Beecem, SiWave, Cygnus, and Runcom.
- Adaptix claims to have already demonstrated system-level mobility based on scaleable OFDMA (Mobile WiMax).
- A market for 802.16e line cards and software will emerge alongside demand for smart antenna software suites, as major fabs and OEMs catch on to Mobile WiMax’s potential
The IEEE expects to publish the 802.16e standard by the end of the year. IEEE 802.16e can use both licensed and unlicensed bands as well as simplex or duplex configurations. Along with mobility support, 802.16e adds several features to the PHY, including OFDMA (Multiple Access), a scalable FFT size (proportional to channel, up to 1000 OFDM carriers) and better Forward Error Correction schemes. It doesn’t play nice with 802.16-2004.
The official, WiMAX interoperability tests begin this July at the CETECOM laboratory in Spain. Certified gear is expected to be available at the end of this year. But it may not matter much for consumers. WiMax, in the 802.16-2004 flavor, is going to be a pt-to-pt backhaul solution.
The money shot is on CPE and basestations that are Mobile WiMax compatible.
The July 2005 802 Plenary Session will be held at the Hyatt Regency San Francisco, July 17-22, 2005.
DailyWireless has more on WiMax: On The Move, WiMax 16d+ Dilemma, WiMax: Will It Stay or Will It Go?, Navini’s Mobile WiMax, WiMax World Wrap, WiMax: HPi – Not, WiMax Procession, Korea Gets WiBro, WiMax Switcharoo, and IEEE Scores 802.16d.
