[CAnet - news] The truth about WiMAX

For more information on this item please visit the CANARIE CA*net 4 Optical
Internet program web site at http://www.canarie.ca/canet4/library/list.html
-------------------------------------------




 [Here is a good article from Dave Farber's IPer list that cuts through all
the hype about WiMAX.  Point to point wireless will have a role to play, but
I don't suspect it will ever be an equal  competitor to wireline services
for high speed broadband except in niche markets.  As the old joke goes,
wireless technology will catch up to wireline capabilities in 2 years time -
this statement will always be true--BSA]

Begin forwarded message:

From: Dewayne Hendricks list

[Note:  This comment comes from reader Robert Berger.  DLH]


>WiMax ranges much as 10 miles, while the WiFi we know today
>reaches only a few hundred feet. Intel wants to use WiMax to allow  
>someone to get wireless access on a laptop anywhere.
>
We all should know by now that the answer to all questions of RF
coverage and capacity is "it depends".
>
WiMax has no magic over WiFi, just additional cost and extra
applications of hype. The modulations are basically the same. The  
WiMax MAC has no more than a 4 dB advantage over WiFi when you  
compare them at the same power levels and antenna gain. That is  
dwarfed by all other considerations such as the fact that multi- 
GigaHertz frequencies barely propagate thru any physical object  
including trees, especially wet trees. Trees are about 15 - 20 dB  
of attenuation most household walls are 10 - 15 dB.
>
Licensed WiMax is allowed to have more power than WiFi. Current
WiMax base stations operate at around 34 dBm of output power,  
Commercial muni-wireless WiFi APs operate at around 24 - 26 dBm. So  
the difference between Licensed WiMax and unlicensed WiFi transmit  
power is about the same as one tree of  obstruction attenuation.
>
To get to a "laptop anywhere" the laptop has to have a transmit
power that is at least in the same ball park as the transmitter.  
Otherwise the laptop can hear the AP, but the AP can't hear the  
laptop.
>
A laptop has severe power constraints, so today most laptop Wifi
transmit power is around 13dB - 18 dB. Its a low probability that  
laptop vendors are going to be putting 24dBm radios into laptops.
>
WiMax CPE (subscriber units) that are being sold in a fixed
configuation have 20 dBm to 26 dBm of transmit power. As does WiFi  
CPE that are being sold for muni-wireless (http://www.peplink.com/ 
productsLoader.php?productName=surf) and are also less expensive  
than the WiMax CPE.
>
This asymmetrical transmit power issue is currently a problem for
muni-wifi deployments as is building and tree obstructions. It will  
be no different for WiMax. But WiFi APs are so dramatically less  
expensive than WiMax that you can afford to have many more of WiFi  
APs thus creating more coverage at a similar cost.
>
And as I have been saying all along, WiFi is recapitulating the
evolution of Ethernet while WiMax is following in the footsteps of  
all the failed competitors of Ethernet.
>
That does not mean that there will not be business successes in
WiMax just as there were some VERY successful ATM and Token Ring  
companies (for a while) .  Intel and others are pouring capital  
down the WiMax drain so it will be good for those companies that  
can pick off that capital while its flowing. Maybe Beceem is one of  
those.
>
I thought that this line was interesting:
>
>Turns out, Intel is having to resell Beceem's chip for Intel's
>WiMax efforts - even though Intel is spending $1 billion on  
>distributing WiMax. You'd think Intel, the chip giant, would want  
>to sell its own chips. You look behind the curtains, and there's  
>only this tiny start-up Beceem doing it all. Intel recently sold  
>off a mobile handset chip unit too, so it doesn't have too much  
>momentum in the mobile space.
>
I wonder how much longer Intel will continue to pour the $billions
into WiMax after they have divested themselves of it.

Weblog at: <http://weblog.warpspeed.com>




-------------------------------------
To SUBSCRIBE:
send a blank e-mail message to
[email protected]

To UNSUBSCRIBE:
send a blank email message to
[email protected]
-------------------------------------

These news items and comments are mine alone and do not necessarily reflect
those  of the CANARIE board or management.

-----------
[email protected]
www.canarie.ca/~bstarn
skype: pocketpro
SkypeIn: +1 614 441-9603


_______________________________________________
news mailing list
[email protected]
http://lists.canarie.ca/mailman/listinfo/news