GNca George
GorillaNET
Premium
join:2008-07-12
Minden, ON
| 3.65 WiMax experiences?
Found a little bit of info about 3.65 WiMax deployments, but nothing too recent.
We were talking with Alvarion yesterday, they claimed that we could reasonably expect better than 900 MHz performance with their WiMax product using 2nd order diversity.
Does anyone here have experience?
George
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Don't steal, Bell and the CRTC don't like competition!!! |
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webformix
join:2009-01-25
Bend, OR
| All the research I've done on Alvarion (and other 3.65ghz WiMAX vendors), leads me to believe that no-one is making an outdoor subscriber CPE that integrates diversity, let alone mimo. I don't understand why vendors are touting their mimo/diversity features at the base station if they don't have the client equipment to take advantage of it. Am I missing something here? |
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AMD Phreak
Premium
join:2003-12-14 | reply to GNca George
correct me if i am not understanding things correctly but doesnt a mimo base station assist signal in even non mimo capable to mimo capable communications? |
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webformix
join:2009-01-25
Bend, OR
| I imagine it depends on how you've setup your mimo/diversity antennas at the base station and what type of client antenna setup you're using.
The recommended base station setup would use dual-polarity, dual-input antennas (h-pol + v-pol).
How can an outdoor CPE unit with a single, integrated, highly-directional antenna, using one polarity take advantage of the above mentioned diversity/mimo setup? The signal from the other polarity would be so low that it would be unusable unless you physically rotated the antenna; thus negating the benefits of any sort of dynamic mimo/diversity.
Now take a mobile/nomadic client using a lower gain omnidirectional antenna, and I think in the above mentioned scenario you might see diversity pay off. |
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GNca George
GorillaNET
Premium
join:2008-07-12
Minden, ON | If I'm not mistaken, Alavarion is advocating same polarity, spacial diversity which seems to make sense. More like a cell site in fact.
George
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Tough Broadband for a Tough Crowd! |
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Nowireneeded
join:2004-02-11
Montoursville, PA | reply to webformix
Yes, you're missing the fact that the main reason you want dual polarity antennas mimo A at the BTS's is you'll be able to hear better at the tower. Adding mimo B on BTS's as well and mimo on cpe only gets better which will be in the coming months. |
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smeghead
join:2009-02-11 | reply to GNca George
Every wimax unit i've tried has been crap. I've had people switch to us over wimax so far. |
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Nowireneeded
join:2004-02-11
Montoursville, PA | Smeghead, what have you tried? |
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smeghead
join:2009-02-11
| reply to GNca George
For example I've had Bell's wimax unit. There is no actual antenna on the roof just a modem you can take with you anywhere and that was absolutely horrible. No matter where you went. I know you can't beat an antenna on the roof that is why I'm not too afraid of 3g.. |
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GNca George
GorillaNET
Premium
join:2008-07-12
Minden, ON
| Bell isn't WiMax, and the newest generation .16e gear bears about as much resemblance to the Bell offering as a fish to a duck. I agree that the Innukshuk/Bell/Rogers product is crap.
George
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Tough Broadband for a Tough Crowd!
GorillaNET.ca - 10Mbits to your desk, coming soon. |
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gunther_01
Premium
join:2004-03-29
Saybrook, IL
| reply to GNca George
We had that Alvarion test setup video on here a while back. I thought it looked promising.. But as others have said Wimax as a whole isn't designed with interference in mind. Since those were all licensed freqs. If that is the case, and add to it multiple WISPS using it anywhere that they may be "overheard" could be a royal PITA.
I would like to try it if I had the funds, but I don't. So that's just my thoughts from reading what I have on it. |
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cmaenginsb
Premium,MVM
join:2001-03-19
Palmdale, CA
| said by gunther_01  :We had that Alvarion test setup video on here a while back. I thought it looked promising.. But as others have said Wimax as a whole isn't designed with interference in mind. Since those were all licensed freqs. If that is the case, and add to it multiple WISPS using it anywhere that they may be "overheard" could be a royal PITA. I would like to try it if I had the funds, but I don't. So that's just my thoughts from reading what I have on it. 3.65 being semi-licensed at least here in the US would reduce or control the possibility of interference.
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CCNA, Comtrain Certified Tower Climber |
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gunther_01
Premium
join:2004-03-29
Saybrook, IL | reply to GNca George
I thought, even though semi-licensed, that there wasn't any restrictions on licensed placement of devices. It read like it was almost part-15, other then the fact you "had" to license.
I should read it again I suppose. |
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cmaenginsb
Premium,MVM
join:2001-03-19
Palmdale, CA
| said by gunther_01 :I thought, even though semi-licensed, that there wasn't any restrictions on licensed placement of devices. It read like it was almost part-15, other then the fact you "had" to license. I should read it again I suppose. There is a requirement for frequency coordination in your area, it's a little more strict than Part-15 but nothing like a real licensed system.
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CCNA, Comtrain Certified Tower Climber |
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gunther_01
Premium
join:2004-03-29
Saybrook, IL | reply to GNca George
That's right, but no real recourse if you two can't agree? Well I guess you could spend thousands trying to "mediate" the issue. But in the end, if you don't agree, what happens??? |
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GNca George
GorillaNET
Premium
join:2008-07-12
Minden, ON
| said by gunther_01 :That's right, but no real recourse if you two can't agree? Well I guess you could spend thousands trying to "mediate" the issue. But in the end, if you don't agree, what happens??? Here's the language IC is using in Canada. Not terribly reassuring...
Wireless Broadband Services (WBS) in the Band 3650-3700 MHz
8.3.1 In-band Interference
Equipment deployed in this band must incorporate contention-based protocols. These protocols are designed to manage the interference between systems without coordination. Because of the implementation of these protocols, the number of licenses awarded within an area will not be restricted. Licensees will not have the same interference protection rights commonly associated with licensed systems. WBS operators should note that, although interference may still be possible, it is expected to be manageable.
The Department will not be involved in coordinating station assignments or resolving interference problems. Licensees are expected to cooperate in order to identify and resolve possible interference issues among themselves. To facilitate cooperation, all licensees will be required to provide site-specific station information and contact information for a publicly accessible database before deploying their equipment.
Decision
Licensees will not have the same interference protection rights commonly associated with licensed systems. The Department will not be involved in coordinating station assignments or resolving interference problems. Licensees are expected to cooperate to identify and resolve possible interference themselves.
Industry Canada will require that licensees provide site-specific data, contact information, including any additional information outlined in CPC-2-1-23, to the Department. Licensees will be required to keep this information up to date.
»www.ic.gc.ca/eic/site/smt-gst.ns···540.html
--
Tough Broadband for a Tough Crowd!
GorillaNET.ca - 10Mbits to your desk, coming soon. |
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Nowireneeded
join:2004-02-11
Montoursville, PA
| reply to gunther_01
This forum sometimes can be run over by those that "think" they understand what is going on and it's sad. If you don't know what will happen to a certain manufacturer's gear when someone interferes then don't speculate. Some manufacturer's have already built in interference resilience into their respective Wimax 3650 products (including GPS sync) and others have not. There are many advantages deploying Wimax over wifi based products but they come at a higher price tag. |
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Chele
join:2003-07-23
| reply to gunther_01
said by gunther_01 :That's right, but no real recourse if you two can't agree? Well I guess you could spend thousands trying to "mediate" the issue. But in the end, if you don't agree, what happens??? They have to play "nice" with each other, the one that doesn't loses! The one provider that had it first has priority, but still has to accommodate the late-commers. The problem is that there is only a 25mHz chunk. Some manufacturers use 7mHz channels, which gives them only 3 channels to avoid interference(even within their own network), where others use 5mHz channels--giving them a bit more leeway. So the potential problem comes when you have more two providers in the same area, it can be difficult to coordinate the channels to avoid interference. As always, some systems(manufacturers) propagate quite well, which causes problems in distant areas where they don't necessarily provide the service. To top it all off, some(if not all) manufacturers don't see the need for horizontal polarization--therefore, their systems are ver-pol only. From what I have read, I will assume it's similar to 900mhz in the way that distant systems cause headaches. I say I will assume because I have never really played with 900mhz systems. |
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AMD Phreak
Premium
join:2003-12-14
| reply to Nowireneeded
said by Nowireneeded :. There are many advantages deploying Wimax over wifi based products but they come at a higher price tag. I think this is the first time I can agree with you.
If the product was from The Batwing or the Big A, I would buy it.
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"No job is so important, and no service is so urgent that we cannot take the time to perform our work safely."
-- AT&T, Your World, Destroyed.
--Safety One Tower Rescue Certified
--LLigetfa:"Wimax is like teenage sex. Everyone talks about doing it." |
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gunther_01
Premium
join:2004-03-29
Saybrook, IL
| reply to GNca George
I find it sad that you think I have not read this. But I read it again just to make my point. Also, all radios are to be contention based. So that they don't slam other radios to the ground. I thought, but that doesn't mean I was wrong fyi. I just wasn't positive. So, I didn't want to say as much. I also understand that WiMax is a different beast. And I am sure that the money is worth it in areas that have an ROI for it. Mine does not, having very small towns to work with.
My LARGEST point, was that it is up to each of us to get along. There is NO exclusive right to this freq range, although a better chance for less interference then your norm part-15. And as such "I" feel (for my company) it could be a very bad financial move to purchase equipment (how many thousands of dollars per site?), have limited freqs to use, have to PRE-register client radios as they are fixed units with the FCC, and then get trampled on by the new/larger company that comes to town. Keep in mind I am in Illinois. It's flippen FLAT out here. There are NO, land masses to block stray signals. I am sorry to have not helped the OP on this topic, but I started out bringing attention to the one video I thought was really well done. And that video was what had me read up on this freq range in the first place.. I now bow out of the conversation.
The rest of this was excerpts from one of the many documents that can be found about 3.65Ghz for FCC land.
»hraunfoss.fcc.gov/edocs_public/a···05A1.pdf
Nationwide, non-exclusive licenses. New terrestrial operations in the band will be licensed on a
nationwide, non-exclusive, i.e., shared, basis with other licensees of the band. However, a licensee is not
authorized to operate a fixed or base station until that station is registered with the FCC. All terrestrial
licensees will have the mutual obligation to cooperate and avoid harmful interference to one another as
well as to protect grandfathered operations, as further described below.
Examine ULS for nearby stations. Licensees should examine the registration database10 before
registering a station and make every effort to ensure that their fixed or base station will operate at a
location, and with technical parameters, that will minimize the potential to cause and receive harmful
interference.(11) We emphasize that coordination is each licensee’s responsibility and that manufacturers of
FCC-certified equipment are not responsible for coordination.
(Foot note) 11 See 47 C.F.R. § 90.1319. Channels are available on a shared basis only and will not be assigned for the
exclusive use of any licensee. Licensees of stations suffering or causing harmful interference are expected to
cooperate and resolve the problem by mutually satisfactory arrangements. Id. |
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