I'm to be responsible for a designing, planning and running a wireless
LAN for a 10days WorldCup summer event here in Denmark/Europe.
The stadium and sourrounding areas will hold up to 15.000 people. 

1) I've been presentet with an unducumented statement that tells me
that a certain density of mobile/GSM phones and wireless LAN does not
go well together. Is this true or not ?

2) If it is true - where can I find information about documentation
and experiences drawn.

3) Is there good statistics about mobile/phone use and sporting events
? How many conversations can we expect ?

4) Links to designs of wireless LAN's for sportsstadiums. Lessons
learned.

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Request for Question Clarification by funkywizard-ga on 10 Nov 2002 05:20 PST

are you expecting to use the common "wifi" 802.11b wireless networking
protocol?

If so, I can tell you right now that you should not expect any
interference whatsoever from cell phones.

If you are indeed planning to use this protocol (it is the most common
one in use) I belive I can provide an excellent answer to this
question (I know a lot about this topic already, but would have to
research some of it).

---

Request for Question Clarification by funkywizard-ga on 10 Nov 2002 05:22 PST

Two more things. Would it be possible to get a general layout diagram
of the sports stadium? Also, how good does coverage have to be? Is
covering nearly every / every seat fine, or do you need excellent
coverage in the other areas of the stadium as well. Is it safe to
assume that the stadium is almost entirely concrete?

---

Clarification of Question by nicolajc-ga on 10 Nov 2002 05:40 PST

Yes, I am planning to use "wifi" 802.11b.

I need some kind of technical documentation that wifi and GSM-mobile
phones do no interfere. I'have never heard that they would - but since
I'm now presented with the question - I need a solid answer.

There is a picture of the grounds on this link:
http://www.vm2003.dk/filarkiv/Grafik/Info%20folder%20engelsk.jpg

I cannot tell you how big the area is - I think the structure is much
ligther than concrete. I have not visited the place yet.

Coverage would have to be acceptable. Mainly the use will be for
results large-screens, officials use, info kiosks, webcams.

---

Request for Question Clarification by funkywizard-ga on 10 Nov 2002 05:48 PST

Ok, I will research this question and report back to you my findings.
I know right now that GSM phones will not interfere, since they
operate in a different frequency range than 802.11b, but since you
need solid evidence, I will find that for you as well.

In the meantime, I would find it very helpful to know how large the
area in question is. Although I realize you said you don't know for
sure, even a very rough estimate would be very helpful. Just the basic
order of magnitude would be a lot better than nothing, i.e., would you
estimate that the area in the picture is closer to 1,000ft on a side
or 10,000 feet on a side?

If you can't get me this information, I still believe I can give a
good answer to your question.

---

Request for Question Clarification by funkywizard-ga on 10 Nov 2002 05:50 PST

One more thing I forgot to mention. Is running any wires possible in
this area, or does everything have to be 100% wireless? Most 802.11b
products are designed to offer a certain range of coverage and send
the resulting data over a wired ethernet connection. This is in
contrast to each wireless access point being able to route data to
each other one. It would be very much more difficult to set up this
network if you cannot run network cables between each access point.

---

Clarification of Question by nicolajc-ga on 10 Nov 2002 06:59 PST

About the size of the ground. I think the whole complex is about 
400.000 mē. square meeters.

I know "wifi" is usually integrated into the wired infrastructure.
I plan for using real cables in where at all possible fx within solid
buildings. But since it is a shortlived event - in many cases it is
cheaper to go wireless than to wire the place up.

My primary concern is the mobile phone implication and where to fine
documentation that this is not a problem.

The "wifi" installation it self is just work.

The first site I came accross that looked promising was a directory of
"European National Frequency Allocation Tables" [
http://www.radioregs.co.uk/frequency_allocation.htm ] which had an
entry for denmark [ http://www.tst.dk/ ]. Unfortunatly, I do not speak
danish, and thus the site was initially of little use to me. Then I
realized that this was likely a 404 error since the page I was seeing
was not the same as the url I specified.

Knowing this, I tried finding a cached version on google, but had no
luck there. Since that didn't work, I tried using the internet wayback
machine, and I found an interesting problem. It loaded the page [
http://web.archive.org/web/20010112081100/www.tst.dk/uk/frequencies/table.htm
] and this appeared to work giving me a page with a list of documents
I could download, but this almost immediately forwarded to their home
page. In order to view this page for a longer period of time, I turned
off javascript in my browser, and at that point I was able to keep the
page from unloading.

This allowed me to get the following link to their list of frequencies
allocated for various usages, including the band occupied by 802.11b [
http://www.tst.dk/rapport/alloc/MHz.pdf ] . However, this link no
longer worked. Luckily, the wayback machine also worked to retrieve
the pdf file as well [
http://web.archive.org/web/20001014230457/www.tst.dk/rapport/alloc/MHz.pdf
], giving me the information I seeked.

On page 17 of this document, it lists those uses allowed for the band
that 802.11b occupies, specifically, the 2.40-2.48 ghz band. For this
area of frequency, it only lists Radio Local Area Network as the
allowed usages. Since there are strict rules in place throughout the
developed world for usage of radio frequencies, it would be illegal
for any cell phone operator to cause interference in this band, since
they are not licensed to use it. Therefore, I believe you to be
reasonably assured no interference from cell phones when using
wireless networking.

Just to make sure, I did a search of the file for "GSM", and I found
that GSM phones are allocated bandwidth in frequency ranges of
approximately 925-960 mhz, far away from the 2.4 ghz frequency used by
wireless networking.

In order to try to make sure I was not wrong on this subject, I tried
the following search [
://www.google.com/search?num=20&hl=en&lr=&ie=ISO-8859-1&newwindow=1&safe=off&q=possible+interference+in+denmark+with+802.11b
] to see if anyone has noticed cell phones interfering with wireless
networking, and this resulted in no relevant information.

Since you specifically stated not to answer question 2 unless question
1 held true, I did not research that particular case. Question 3
seemed to follow the same lines, and thus I assume that you do not
need this data unless I were to find that phones interfered with
wireless networking. If this assumption is wrong, please let me know
and I will do my best to answer part 3 as well.

As for part 4, Although I had little trouble finding consumer oriented
stories about stadium wireless networks (links below), I had extreme
difficulty in finding information relating to the challenges of
installing them. I was able to find that Microsoft's website has a
case study on implementing wireless lans in sports stadiums [
http://www.microsoft.com/mobile/enterprise/casestudies/cs-coors.asp ].
However, this article clearly was designed to make microsoft look good
and to sell more software, and as such, did not highlight any
potential problems you may face.

I found one interesting article about the usefulness of wireless
networking in stadiums [
http://www.icewrx.com/pdf/autraliait_staples.pdf ], but does not
really relate to installation related issues. Another article [
http://augustachronicle.com/stories/100100/tec_LF7042-6.000.shtml ]
talks about the "gee whiz" factor of having wireless networking in a
football stadium, but again, is light on the type of details you
desire.

In all, I found literally dozens of websites trying to convince
potential wireless network installers that their products will solve
all their problems, and another couple dozen websites trying to tell
consumers about the wonderful opportunities they may see in the future
with wireless networking in public areas, and yet another dozen or so
articles saying how great it will be for businesses to have wireless
networks in public areas such as sports arenas, but in over 1 hour of
searching, I could not find one decent article about the potential
problems one might face installing a wireless network in a large area
such as a stadium.

If the information I have provided is enough, I would be happy for you
to inform me as such. If however, I need to provide more information
for you to be satisfied with my answer, please request a clarification
and I will be glad to provide it. Specifically in regards to the 4th
part of your question, if you find my response insufficient, would you
be willing to accept general information on potential problems that
one might face while installing wireless networks?
 
search strategy

://www.google.com/search?num=20&hl=en&lr=&ie=ISO-8859-1&newwindow=1&safe=off&q=frequency+allocation+denmark

://www.google.com/search?q=possible+interference+in+denmark+with+802.11b&num=20&hl=en&lr=&ie=UTF-8&newwindow=1&safe=off&start=20&sa=N

://www.google.com/search?q=installing+wireless+networks+in+stadiums%2C+experience&num=20&hl=en&lr=&ie=ISO-8859-1&newwindow=1&safe=off

://www.google.com/search?q=wireless+lan+sports+stadium&num=20&hl=en&lr=&ie=ISO-8859-1&newwindow=1&safe=off&as_qdr=all

Thanks for the research. I'm looking forward to reading the links.
I stumpled upon the fact that Avaya did it for the soccer WorldCup in Japan 2002.
http://worldcup.avaya.com/