[1st-mile-nm] Information request on wireless reliability and frequency conflicts

[Bob Knight]

You need to look at the WISPA archives relative to Motorola Canopy. 
While it is the largest deployed base in that community, it also is 
considered to be the largest problem interference-wise, at least in the 
2.4 (not 2.6) Ghz band. In our area, though, they're using 900 Mhz.

In 2.4, there are 11 channels (in the US, at least). Ideally (and 
nowadays, this is far from ideal given the spectrum pollution), one 
wants things 5 channels apart, especially when hidden node problems are 
anticipated. The problem is that hidden node is going to be a problem 
pretty much no matter what measures you take.

WiMax can be used in various bands from 2-66 Ghz. 2.5 and 3.5 are 
licensed spectrum and it can be used in 5.8. It seems to be suited to 
700  Mhz as well.

Our experience on 5.8 is very positive. We use it for our backhauls. One 
nice thing about this spectrum allocation is that the channels are 
non-overlapping. Our backhaul sink for the DS-3 has 5 different links 
coming in with no interference.

Admittedly, we are rural. But I guarantee that if the Santa Fe spectrum 
in 5.8 (or Eldo for that matter) were crowded, we'd see it. And we don't.

So where are you seeing problems?

Bob

peter wrote:
> We are involved in several projects investigating wireless conflict 
> signals within corporations and hospitals and are finding some strange 
> results which could impact Wi-Fi and Wi - Max usage and indeed the 
> whole paradigm first mile wireless use.
>
> Basically this is what we are seeing
>
> Open wireless frequencies that have been typical used are 900 - 2.6 
> and now 5.8ghtz.
>
> 802.11 of various types operates in both the 2.6 and 5.8 sectors ( 5.8 
> is 802.11n and 802.16 wi max )  the 900 htz range is packed and so is 
> the 2.8 ghtz
>
> Inside of a hospital for instance multiple monitoring equipment types 
> and portable phone systems operate on the same frequencies and so does 
> a huge amount of SCADA operations.
>
> Although channel switching is supposed to prevent signal conflict 
> wi-fi  signal boosters and all wimax whether static or mobile is 
> continually channel hunting and knocking everything else of of the 
> channel making many types of systems non usable
>
> It would seem that a major problem is manufacturers testing their 
> equipment in a silo arena and this would also be relevant to the white 
> space transmission requests before the FCC at present
>
> This looks like a huge problem and if anyone is experiencing the same 
> issues please contact us
>
> Apparently Motorola with their Canopy system and Intel ( wi-fi and max 
> ) did a large amount of research  but when the conflict issues arose 
> chose to ignore the results or assumed that channel frequency switch 
> would fix the problem but its not
>
> ( : ( : pete
> -- 
>
> Peter Baston
>
> *IDEAS*
>
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>
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> /_Mailto:pete at ideapete.com <mailto:pete at ideapete.com>_/
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