Posted on 07/24/2005 6:31:51 PM PDT by kerrywearsbotox
A GMC Yukon Denali motors down the road, while the passengers inside simultaneously receive mobile calls over the Internet, and streaming video at up to 2.5 Mbps, on a variety of devices. Cutting-edge? You bet, but that technology demonstration took place just last week in Vancouver, and it was designed by engineers to show the potential of the newest mobile-phone technology: mobile WiMax. WiMax -- a nerdy acronym for Worldwide Interoperability for Microwave Access -- in the coming years may become the new mobile-phone standard, experts told UPI's Wireless World.
(Excerpt) Read more at washingtontimes.com ...
Yet another media report about a self-driving SUV... at least this time the vehicle isn't committing some horrible crime.
With WiMax poised to usher in the second coming of fixed wireless broadband, two Institute of Electrical and Electronics Engineers (IEEE) (define) working groups are turning their attentions to mobile broadband so you can use that high-speed connection on the road.
The emerging 802.16e and 802.20 standards will both specify new mobile air interfaces for wireless broadband. On the surface the two standards seem very similar, but there are some important differences between them. For one, 802.16e will add mobility in the 2 to 6 GHz licensed bands, while 802.20 aims for operation in licensed bands below 3.5GHz.
More importantly, the 802.16e specification will be based on an existing standard (802.16a), while 802.20 is starting from scratch. This means that products based on 16e will likely hit the market well before .20 solutions -- a distinct advantage for the WiMax Forum, the group currently backing 802.16 and its permutations.
The IEEE approved the 802.16e standards effort in February with the avowed intent of increasing the use of broadband wireless access (BWA) by taking advantage of the "inherent mobility of wireless media." The amendment to 802.16, which is also called the wireless metropolitan area network (MAN) standard, will enable a single base station to support both fixed and mobile BWA. It aims to fill the gap between high data rate wireless local area networks (WLAN) and high mobility cellular wide area networks (WAN).
There could be a draft of the .16e standard as early as the middle of 2004, according to Brian Kiernan, the chair of the .16e Task Group. This would give it quite a head start over 802.20, which is still in the very early stages of development.
The IEEE actually established the 802.20 Working Group before it gave the go-ahead to 802.16e and indicated that it intended to have a standard in place by the end of 2004, but the group has been mired in conflict (a battle for the chairmanship is currently underway) and has made little progress.
The 802.20 interface seeks to boost real-time data transmission rates in wireless metropolitan area networks to speeds that rival DSL and cable connections (1Mbps or more) based on cell ranges of up to 15 kilometers or more, and it plans to deliver those rates to mobile users even when they are traveling at speeds up to 250 kilometers per hour (155 miles per hour). This would make 802.20 an option for deployment in high-speed trains. The 802.16e project authorization request specifies only that it will "support subscriber stations moving at vehicular speeds"; Kiernan said the group has achieved speeds of 120 to 150 kilometers per hour (75 to 93 miles per hour) in simulations.
There is clearly some overlap between the two standards, but the party line from companies involved in the 802.20 standards effort, including Navini Networks and Flarion Technologies, is that the two are not competitive. The IEEE would not ratify a group that has competing interests with an existing group, argued Sai Subramanian, vice president of product management and strategic marketing at Navini. "If they are so obviously in conflict, why did IEEE approve two standards tracks?"
Not everyone is buying that argument, though. "The bottom line is they're very similar," said Ed Rerisi, director of research at Allied Business Intelligence (ABI). "They do have some minor differences, but they both are aimed to serve similar users."
Essentially, 802.16e is looking at the mobile user walking around with a PDA or laptop, while 802.20 will address high-speed mobility issues, he said. One key difference will be the manner in which the two are deployed. "Our assumption is that the carriers are going to deploy .16e in their existing [.16a] footprint as opposed to deploying a more widespread footprint, like a cellular network, for example," said Rerisi. "802.20 is looking at more ubiquitous coverage ... and that will require a larger footprint."
Indeed, some argue that 802.20 is a direct competitor to third-generation (3G) wireless cellular technologies. Since mobile operators are spending millions to upgrade their networks in order to offer 3G services, it could be a tough sell to persuade them to invest in yet another network.
It doesn't have to be an either-or situation, though, said Ronny Haraldsvik, senior director of marketing strategy at Flarion Technologies, which has been heavily involved in the 802.20 standards process. He said that operators could deploy 802.20 as an overlay to their existing networks. "They don't have to walk away from what they have."
In the meantime, 802.16e's head start may actually work to 802.20's advantage by whetting users' appetites for mobile access, Rerisi suggested. "If 802.16e drives demand initially and people are getting thirsty for it, a .20 solution could be deployed on a widespread basis and take advantage of users wants and demands for high-speed data."
Ultimately, the fate of both standards rests with 802.16, he said. "I think that if there's success in the 802.16 market, it'll definitely portend good things for the 802.20 market."
is this faster then fiber or will it ever be faster then fiber
When fiber-optic cable first came out, it was 100Mb/s, and there was talk of fiber to the desktop until technological advances pushed the capacity of copper twisted-pair cable to equal speed, then to gigabit speeds.
On the other hand, fiber-optic cable with the development of Dense Wave-Division Multiplexing (DWDM), now has the capacity to carry multiple frequencies of light travelling down a single fiber - it started at 16 channels per fiber, but is now in the hundreds of channels per fiber, allowing thousands of gigabits per second to be transmitted.
So, no, it's not faster than fiber and the laws of physics suggest that it will never be faster than fiber.
Thank you very much for the info.
Technically, from a physics point-of-view, wireless can be made as fast, if not faster than fibre optic medium. Both light and radio waves travel at the same speed in vacuum.
I don't know if wireless data can be sent through multiple channels simultaneously, as is the case with fibre, but I presume it should be possible with radio too.
Does radio in air travel faster than light in a fibre cable?
Another point to ponder is that the slower connection will be the one which uses more repeaters, as these electronic "bridges" and amplfiers are speed bottlenecks.
Technically, from a physics point-of-view, wireless can be made as fast, if not faster than fibre optic medium. Both light and radio waves travel at the same speed in vacuum.
I don't know if wireless data can be sent through multiple channels simultaneously, as is the case with fibre, but I presume it should be possible with radio too.
Does radio in air travel faster than light in a fibre cable?
Another point to ponder is that the slower connection will be the one which uses more repeaters, as these electronic "bridges" and amplfiers are speed bottlenecks.
Thanks for your information.
It's not the speed of the signal, it's the modulation and the available spectrum.
There's only a certain amount of bandwidth available over the air due to interference with nearby signals on the same frequencies, and there's only a certain number of bits per second that can be transmitted over a given frequency via modulation of the signal. The higher the frequency, the more bits can be transmitted per second.
Fiber-optic cable operates in infrared frequenices, which is eight orders of magnitude higher frequency than FM radio and five orders of magnitude higher frequency than microwave radio typically used for long-distance wireless links.
Here's a good intro: http://trace.wisc.edu/docs/ir_intro/ir_intro.htm
Through direct-sequence and frequency-hopping spread-spectrum techniques, the bit capacity of a given range of radio frequencies can be multiplied, but the advantage of fiber is that each fiber has its own private bandwidth, not subject to interference by any other fiber or external signal.
As for repeaters, they haven't had to do electronic conversion of fiber-optic signals for amplification in 15 years - Erbium-Doped Fiber Amplifiers were introduced in the late '80s and use a "pump" laser and a section of erbium-doped fiber cable to amplify a narrow band of frequencies, amplifying all channels of early WDM systems simultaneously.
And in 2001, Bell Labs developed a new, inexpensive type of amplifier called a "Raman amplifier," that also does not need to do any electrical conversion of the fiber signal - http://www.answers.com/topic/raman-amplifier - and operates over a much wider frequency band than the EDFA.
For years they've had systems that can convey 1.28 trillion bits of data per second over a single fiber for 2,500 miles without electronic regeneration.
Thanks for the info. Anyway, I wanted to mention that my earlier answer was from the physical aspect of it, in pure isolation, and you pointed out about the problems arising from interference owing to other sources of radio energy.
Hmmm. That was good information. Thanks!
No. The entire marketing concept for 802.16 is for broadband speeds for a MOBILE user. The speeds thrown around in that article are a bit ambitious. The concept of a mobile high-speed is intriguing, but I can't foresee any telephone companies wanting to invest in yet another technology that might be "leapfrogged" again.
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