On 10 Jan 2006 00:40:15 -0800,
(E-Mail Removed) wrote:
>Wonder if I could have your opinions on something. Lots of enterprises
>have an internal telephone network, but now are also providing
>employees with mobile/cellular phones so they can work away from the
>office.
>
>At the same time, most of these voice networks are "traditional"
>telephone switches. These are evolving towards voice over ip (VoIP).
>In the last few years, push email has proven immensely popular. Does
>WiMAX present a solution to these developments?
Nope. It presents and enabling technology. Basically you can do VoIP
over anything that supports the bandwidth. If you want, you can do
VoIP over an ISDN B1 line. WiMax is just one of many wireless data
formats that can be used for VoIP.
Since when is "push" email been proven immensely popular? Just about
all the push technology vendors have gone bankrupt because of the lack
of a suitable business and revenue model.
> - deploy a WiMAX base station in the enterprise
Yeah. Just don't forget about the little details like RF propogation,
bulding penetration, interference mitigation, and reliability. I
really like the term "deploy" as it implies that everything will work
when you turn it on.
> - use a "smart" phone with WiMAX and GSM/GPRS/3G capabilities
WiMax is a potential competitor to cellular data (1xRTT, EV-DO, HSDPA,
etc). With WiMax, your corporate user will be able to make calls for
free with the company WiMax system, and metered rate from the cellular
service provider. At this time, free wide area calling on the
cellular networks has taken all the potential cost benifits out of
VoIP on cellular data. Also not that you can replace the WiMax with
802.11b/g or Bluetooth in the phone and get the same results.
> - while at or near the office, the "smart" phone can use the WiMAX
>network to carry calls, as well as data, for example push email. This
>would be "free".
Yeah, that's the plan behind the dual mode phones. Of course the
cellular providers are doing everything they can to prevent the user
from running VoIP on their instruments. For example, Verizon disables
all of the Bluetooth OBEX profiles, half the Bluetooth features,
prevents the installation of an 802.11 card, and generally does
everything it can to cripple the instrument to promote its own
services.
> - while away from the office, switch to GSM/GPRS/3G
Sure. However, most users can live with just voice and don't need the
expensive data service.
>Advantages;
> - users need only one phone/device (not a desk phone, and a
>mobile/cellular phone, and a Blackberry)
The average turnover on cellular handsets is 18 months. In effect,
the handsets are almost free. Why would a company pay a substantial
amount of money for a single instrument to replace an almost free
phone and possibly a cheap PDA with 802.11b/g? I don't see the
savings with internal VoIP to justify the added cost of the
instrument.
> - develop a VoIP infrastructure to replace traditional "switched"
>voice network (if phones resemble cellular/mobile phones, are
>rechargeable with days of bettery life, there's no need to worry about
>Power over Ethernet (PoE), air conditioning/uninterruptible power in
>wiring closets, etc which makes switching to VoIP/PoE expensive and
>difficult)
This reeks of the old debate between the dumb network and the smart
network. In my never humble opinion, I don't need a smart network.
Just a smart phone. The phone and the user are perfectly capeable of
making intelligent decisions and do not require a telco or cellular
intrastructure to do it for them.
> - WiMAX supports QoS at the MAC layer, making it better suited to
>VoIP/video, etc
*ALL* 802.11b/g wireless and WiMax are done at the MAC layer. Note
the word "ALL". QoS can be done on layer 2, 3, or both, but is
mostly commonly done in wireless on layer 2. No benifit.
> - mobile WiMAX means a single base station could cover the entire
>business "campus", easier than many Wi-Fi access points.
Coverage will be improved by an increase in base station power output.
However, unless the client radios have a similar increase in transmit
power, range will be largely the same as 2.4GHz 802.11b/g. To it's
credit, WiMax is more efficient than 802.11b/g, so one should be able
to cram more users into a give bandwidth.
Also, there are severe limitations to trying to cover a large "campus"
with a single access point. The big one is that in building coverage
below the central access point is really awful. Another is that big
tall antennas on high buildings tend to pickup interference from
neighborhing systems.
> - many employees live close to work, so may well be able to use
>corporate network from home for "free". (assuming 30 mile coverage!)
The 30 mile coverage is science fiction. References and calcs on
request.
Well, actually one could do 30 miles with proper antennas. It's not
going to happen with a minimal cell phone antenna. Visualize your
corporate user plugging their conglomerated WiMax cell phone into a
24dBi pizza dish on their roof or vehicle. I don't think so.
> - Intel envisions incorporating WiMAX in future revisions of Centrino,
>making PC support "semi-ubiquitious"
They also visualize SDF (software defined radio) and WUSB (wireless
USB) using UWB (ultra wide band). They're also behind MIMO as the
answer to all problems. If Intel's record of delivering their 802.11b
chips (which they bought from Philips) 2 years late is any indication
of their support, I would not consider this to be an advantage.
>Am I barking up the wrong tree? Would the big names (Nokia, Ericsson,
>and now Cisco/Avaya/Nortel) see a future in this? Intel is clearly
>very optimistic about this technology.
Reality and press releases are mutually exclusive. These companies
will claim to support any technology that pumps up their stock and
gets them the attention of the press. If it shows any sign of
failure, they will kill it instantly. Want to invest in some Intel
Bubble Memory modules? As a rule of thumb, products are ready for
prime time 18 months after the initial chipset samples arrive.
>Tried googling for perspectives on this, but can't find anything
>relevant. Think this is achievable from a technical perspective, but
>how likely is it?
This is not a technical discussion. It's about industry politics and
trying to predict the direction in which the technology will stagger.
I suggest you read some of the articles at:
http://www.outlook4mobility.com/commentary.htm
including a few on WiMax. Hopefully that will give you a modest dose
of reality. One interesting point that Andy makes is that no data
only service has every made money (except for a short period when the
one way pager service providers were claiming profits).
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
(E-Mail Removed)
#
http://802.11junk.com (E-Mail Removed)
#
http://www.LearnByDestroying.com AE6KS
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