What's interesting about WiMax

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What would you deem as the most interesting part of WiMax. Would you
say protocols? Architecture? or anything else.


Re: What's interesting about WiMax



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My opinion: very secure wireless, inexpensive, good speed, and non
line-of-sight.  What else can one ask for!

EW



Re: What's interesting about WiMax


On Fri, 13 Jan 2006 18:12:57 -0600, LoneStar wrote:

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What frequency are they planning to operate it on ?  I heard it's around the
400Mhz area.. that right ?

Re: What's interesting about WiMax


Doz wrote:

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http://www.wimaxforum.org/news/downloads/WiMAX_to_Bridge_the_Digitaldivide.pdf
The two licensed bands 3.3-3.8 GHz and 2.3-2.7 GHz
One license exempt band 5.725-5.85 GHz.

Long:-
http://www.wimaxforum.org/news/downloads/Applications_for_802.16-2004_and_802.16e_WiMAX_networks_final.pdf
Short:-
http://tinyurl.com/b357j

Re: What's interesting about WiMax



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Clearwire, Nextel and Sprint own most of the 2.3/2.7GHz MMDS/ITFS
licenses.  At this time, Sprint has some MMDS systems:
  http://www.SprintBroadband.com
with existing customers that will need to be "transitioned" before
they can deploy a WiMax system.  Nextel isn't doing anything, but will
probably follow whatever Sprint does.  There's rumors of conglomerated
Cellular and WiMax phones, but I haven't seen anything real.

Clearwire is currently using 2.5 - 2.7GHz.  They're using a slightly
proprietary version of WiMax.  In Europe, Clearwire and MAC Telecom
have licenses for 3.5GHz.

TowerStream uses the 5.8GHz unlicensed band.

The newly allocated unlicensed 3.6GHz band doesn't seem to be getting
much attention due to lack of equipment and location restrictions.
50MHz is not enough and it should have been the same as the European
3.5GHz band, which is 200MHz wide.   The goofy protocol requirements
and restrictions are rather excessive.  I'm sure the telcos will do
everything they can to insure that the FCC makes life miserable for
WiMax service providers.  Still, it's the only band that isn't already
auctioned or polluted.
|  http://dailywireless.org/modules.php?name=News&file=article&sid=4324&src=rss10
|  http://www.broadband-wireless.com/magazine/volume.asp?vol=52&story=478

There are some small local providers doing WiMax on 2.4Ghz.  I don't
have the names handy.  Seems to work fairly well from mountain tops.

The public safety groups are looking into WiMax on their 700Mhz and
4.9GHz bands.  Most of the vendors are doing everything they can to
avoid industry standards and are trying to lock in the public safety
users into proprietary technology.  This is traditional in the public
safety market and is the major reason why standards based technologies
such as Project 25 have rotted in place for 15 years.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: What's interesting about WiMax


On Wed, 18 Jan 2006 10:28:19 -0800, Jeff Liebermann wrote:

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surely one of the benefits of Wimax was portability and roaming.. Not exactly
workable if you have to keep LOS with thos freqs.

Re: What's interesting about WiMax



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In my never humble opinion, NLOS (non-line of sight) is not reliable.
OFDM is a giant step in that direction, but you must recognize that
such post processing has its limitations.  What ODFM and WiMax do is
combine the reflections into a useable signal through heavy duty DSP
(digital signal processing).  That works fairly well but is not 100%
reliable.  What happens is that the reflections tend to change rapidly
as the user moves.  The result is dropouts and fades at points where
the reflections don't quite combine into something useable.  It also
produces rather drastic changes in thruput as one moves.  In other
words, it's not perfect and tends to unreliable.  The result is that
you can probably get an NLOS connection, but staying connected is not
easy or guaranteed.  How often you want your WiMax VoIP call to be
dropped is the question.

As for roaming, that has only recently been recognized as a problem
worth solving.  The result are alliances such as WISPr and WGRA
dedicated to making it work.
  http://www.wimaxgra.com
  http://www.wi-fialliance.org/opensection/wispr.asp
I think WGRA is defunct (not sure) and WISPr has been implimented in
at least 4 different ways that will eventually become 802.11r for
Wi-Fi in perhaps 3 years, and is being worked on for "Mobile WiMax" as
part of 802.16e.
  http://www.ieee802.org/16/tge /
The standard is scheduled for publication at the end of Jan and things
should hopefully progress rapidly after that.

As for frequencies, a hertz, is a hertz, is a hertz.  Propogation is
completely independent of modulation, protocol, and political
influence.  Propogation is similar to 1.9Ghz PCS cell phones, except
that instead of about 30KHz of bandwidth per user, WiMax bandwidth is
MUCH larger.  All other things being equal (tx power, rx sensitivity,
antennas, and losses), the larger bandwidth has a proportionatly
smaller range.  It's not exactly linear but close enough for a crude
approximation.  If your 30KHz PCS phone can talk reliably over a 5
mile radius cell, then WiMax at 2.3/2.5Ghz, running 1000Kbits/sec will
work over:
  30Kbits/sec  /  1000Kbits/sec * 5 miles = 0.15 miles radius.
In other words, if you want speed, you gotta either have more signal
to play with, or install more "cell" sites to cover the area.  Again,
this is an oversimplification and should not be used for calculating
coverage or range.  However, it does illustrate the principle and
limitations of WiMax.

One nice thing about WiMax is that it's more resistant to interference
that other protocols.  This is important because at the present growth
of wireless everything, interference will probably be the limiting
factor in deployements and service reliability.

  
--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: What's interesting about WiMax


On Mon, 23 Jan 2006 09:46:41 -0800, Jeff Liebermann wrote:

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Thanks for the info Jeff,

In your opinion (highly valued on here I might add!) do you think standard wifi,
ie. g,b modes could be replaced by Wimax (all be it with lower power for shorter
ranges) ?

Regards,

Doz

Re: What's interesting about WiMax



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I try to stay away from predicting the future, but I'm also not very
good at resisting temptation.  I'll try to be coherent.

Without dedicated frequencies, WiMax will not function.  Without a
major service provider pushing for deployments, it will not be
adopted.  Without economical hardware, it will not be affordable.  As
long as the telcos consider WiMax to be competition for their EV-DO
and HSPDA, it will not have regulatory backing.  I don't see adoption
of WiMax for small scale networks because WiMax doesn't offer much
that 802.11b/g/r/n/etc does today.  Too many obstacles, methinks.
There will be deployments, but only in areas that make sense (i.e.
where there's no competing infrastructure).

Also, consider that 802.11 has only been a specification since 1997.
802.11 didn't really become cheap commodity technology until about
2003.  That's 6 years from spec to commodity.  802.16 has only
recently been approved.  Bluetooth took about 5 years.  Wanna wait 5-6
years for WiMax?

Personally, I think UWB (wireless USB) will be the next big thing.
That's because it fills needs (very high speed local wireless data and
removal of the cable tangle) that can't be done any other way, and
that there are no regulatory obstacles.  It also doesn't interfere
with existing wireless technologies.  If you're looking for indoor
WiMax to replace 802.11, I suggest you consider wireless USB as a
possible alternative.

Disclaimer:  
This is my opinion which should not be confused with reality.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: What's interesting about WiMax


Jeff Liebermann wrote:

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Shame then that IEEE has abandoned the UWB standard, but has moved
forward on 802.11n.

David
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Re: What's interesting about WiMax



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Forward?  You mean final approval predicted for Sept 2007?
  http://www.ieee802.org/11/802.11_Timelines.htm
802.11n has been in process since Sept 2003.  My guess(tm) is we'll
have UWB chips and systems before 802.11n is approved.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: What's interesting about WiMax


On Thu, 26 Jan 2006 21:53:09 -0800, Jeff Liebermann wrote:

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Yes I agree..  roll on UWB.. I'll have a bag of dongles instead of a nest of
wires any day!

Re: What's interesting about WiMax



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The most exciting thing to me is that WiMax could become something
that's offered commercially but can still be deployed by individuals.
That means I can get WiMax service from someone like Sprint but still
have my own WiMax stations at my home, farm, campus, wherever.

It's much like WiFi except at more usable distances.  I get *really*
excited thinking about WiMax VoIP handsets.  Make this one WiMax and
the possibilities are amazing.
    http://www.linuxdevices.com/news/NS8333775927.html

--kyler

Re: What's interesting about WiMax


[POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]


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The problem is that interference tends to increase with range.
Spectrum is finite.

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