Clearwire: Just Say No

Fri Feb 2 20:31:36 PST 2007

NextNet (Motorola) 'Expedience' equipment is precursor to WiMAX: It uses 256 
FFT OFDM TDD similar to 802.16d-2004.  But it does not use the technologies 
needed to make it more dynamic and mobile including MIMO-AAS-OFDMA and 
higher order, scaleable modulation and FFT used in 802.16e-2005.

There are two initial 'waves' of WiMAX mobile.  Most vendors preparing to 
submit products to qualify for Wave 2 which will inlude manditory support of 
MIMO.  And some chip suppliers and vendors have developed enhanced versions 
which can include higher order MIMO and smart adaptive antenna capabilities. 
Although most vendors are already using some type of AAS in their base 
stations, some will include beam forming in the subscriber units as well. 
Navini has been a leader in bringing beam forming into the CPE/SU.  A lot of 
work is occuring in MIMO-AAS developments that are tied closely to the 
underlying modulation scheme.  WiFi, 802.11n, is hampered by the limited 
number of channels and modulation scheme.  WiMAX will far exceed that in 
Wave 2 and will advance further with future versions.

We may see development of the modulation scheme that are closely tied to the 
use of MIMO-AAS: Quasi-orthogonal modulation and other methods may be used 
to align orthogonality at multiple levels within sets of subchannels.  This 
can reduce overall complexity, a major problem with the use of higher order 
MIMO in mobile, long range, and comlexly architected systems.

Another trend is development of Smart Wireless Networks: networks that can 
do much of their own 'self set-up and managment'.  This also extends to 
multi-dimensional spatial networks.

The first phase is just getting mobile (wave 2) developed and WiMAX 
deployed.  That will be a mjor improvement over Clearwire's current NN 
product and will be supported by several system and end user equipment 
suppliers.  Significant mobility won't happen until 2008 because it takes 
both network base station density and end user devices to support broadband 
mobility.  WiMAX is falsely claimed to be a long range system: it is 
somewhat shorter range than cellular but can delivery higher bandwidth.  If 
you want to build a system to support many users with high bandwidth, you 
have to install base stations more densely and back haul the needed 
capacity.

----- Original Message ----- 
From: "Steve Stroh" <steve at stevestroh.net>
To: "SeattleWireless Talk List" <talk at seattlewireless.net>
Sent: Thursday, February 01, 2007 1:55 PM
Subject: Re: Clearwire: Just Say No

>
> Clearwire (actually, the vendor, NextNet Wireless, now Motorola)
> makes a mobile-specific version of the "Clearwire" modem, but it
> requires a trunk-mount installation (much like an old mobile two-way
> radio) and a permanently mounted external antenna on the vehicle.
> They market these units primarily to public safety and government.
>
>
> Thanks,
>
> Steve
>
>
>
> On Jan 26, 2007, at Jan 26  12:13 PM, Patrick Walters wrote:
>
>> I was  interested in ClearWire but until they have a PCMCIA Card I
>> can slip in my laptop It's just silly to cal it city wide access.
>>
>> Although, apparently the BestBuy Geek Squad have one in those bugs
>> hey drive around so they can access the internet from anywhere.
>> That is kind of cool. The A-Team would have had one in their van
>> I'm sure. ;-)
>>
>> -=p
>>
>>
>> -----
>> Patrick's Sailing Blog - http://www.shipsrecord.com/blogs/patrick
>> <http://www.shipsrecord.com/blogs/patrick>
>>
>>
>> ________________________________
>>
>> From: talk-bounces at seattlewireless.net on behalf of Tom Marshall
>> Sent: Fri 1/26/2007 10:50 AM
>> To: talk at seattlewireless.net
>> Subject: Clearwire: Just Say No
>>
>>
>>
>> I have just had the most awful experience with Clearwire and I
>> wanted to
>> warn others on this list just in case they were considering signing
>> up for
>> it.
>>
>> I figured it would be cool to get wireless broadband for a
>> reasonable price
>> so I tried to sign up via their website.  That didn't work -- the
>> website
>> did not allow me to sign up with my address, even though addresses
>> as close
>> as two blocks away in any direction did work.
>>
>> So I called up clearwire sales.  The sales rep ran into the same
>> issue so he
>> entered my work address into the system in order to let him make
>> the sale.
>> In retrospect, this should have been a big warning sign, but I
>> didn't think
>> anything of it at the time.
>>
>> I'm a firm believer in providers being providers and staying out of
>> the
>> firewall business, so one of the very first questions I asked was
>> whether
>> they blocked any ports at all.  The sales guy was very nice and
>> upfront and
>> said he didn't know, so he transferred me to tech support.  The
>> tech support
>> rep assured me that no, they don't block any ports at all on their
>> side.
>>
>> Once I received the modem, I plugged it in and was unable to get a
>> strong
>> signal.  I spent quite a long time walking around my house waving a
>> modem
>> around in the air like a dork but the best I could get was a marginal
>> signal.  I've made several calls to tech support and they all say
>> that I'm
>> well within range of at least two towers (about 0.25 miles to
>> either) and
>> they just can't understand why my signal is so bad.  Today (two
>> weeks later)
>> they finally decided that they can't fix the problem over the phone
>> and they
>> actually have to send someone out to my house.  So sometime in the
>> next
>> three days I'll have the added inconvenience of scheduling a time
>> to miss
>> work so I can let a technician into my house and wave another modem
>> around
>> in the air.  If he can't get a good signal, they may want to mount
>> a modem
>> outside my house and that's sure to be another uphill battle (I'm
>> not keen
>> to put holes in my house to support a crappy service with
>> technicians that
>> lie to me in order to make a sale).
>>
>> Meanwhile, I went out and purchased a Linksys WIP300 and tried to
>> get it to
>> work with the marginal clearwire service.  I spent all night trying
>> to get
>> it to place calls but was unsuccessful.  Yesterday, I was at Racha
>> in Queen
>> Anne and I noticed they had free WiFi.  So I decided to give the
>> phone a try
>> there.  Worked like a charm.  Next I tried from work.  Again, it
>> worked
>> great.  So I went home last night and did some investigation.  I
>> did some
>> monitor-mode packet captures using my laptop while I tried to place
>> calls
>> with the phone.  The SIP packets were going out but nothing was
>> coming back.
>> So I figured maybe my wireless router (a WRT54G) was at fault.  I
>> tried
>> everything to get it to work -- everything failed.
>>
>> So I figured I'd call clearwire support to see if they could
>> resolve the
>> issue.  The tech support rep immediately told me that they block
>> all ports
>> but that customers can request ports be opened.  But, I explained,
>> the first
>> tech support rep said that there was no port blocks on the
>> service.  He said
>> that was "not the truth" -- I had been lied to in order to make a
>> sale.  So
>> in order to open the VoIP ports (that I am paying for, that should
>> be opened
>> anyway, and that I was told would be open when I signed up), I need
>> to fill
>> out a request that includes detailed information about what
>> application I
>> plan to use, why I need it, and so forth.  Then the request goes up
>> to the
>> next level and some anonymous network manager gets to decide
>> whether my
>> request is acceptable.  If they do choose to allow the requested
>> ports,
>> their policy is to open the ports within six (6) business days.
>> Yes, that
>> is more than a full week.
>>
>> So if you are planning on getting clearwire, make sure that (1) you
>> get a
>> GOOD STRONG signal, and (2) you don't need to use it for anything
>> but web
>> browsing -- VoIP, VPNs, and anything else that your average AOLer
>> doesn't
>> use on a regular basis are subject to filtering and the whims of their
>> network managers.
>>
>> If the "technician" that shows up at my door next week can actually
>> get the
>> modem to provide a clean signal, I get the privilege of setting up an
>> encrypted tunnel to a server outside the reach of clearwire's idiotic
>> firewall policies in order to get access to arbitrary IP traffic
>> that have
>> already paid for.  Obviously I'm hoping that he can't fix it and I
>> can go
>> find a provider that isn't so unfriendly to the tech savvy community.
>>
>> --
>> Innovate, v.: To annoy people.
>> _______________________________________________
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>>
>>
>> <winmail.dat>
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>
>
>
> ---
>
> Steve Stroh
> 425-939-0076 | steve at stevestroh.net
> Writing Writing about BWIA again! - www.bwianews.com
>
>
>
>
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