[Loadstone] Possibility to ignore Cellid...

Grzegorz Zlotowicz grzezlo at gmail.com
Fri Oct 9 02:30:57 BST 2009


Hi,
not all operators provide the text description of your actual place, so in 
India this info is provided, in the places where you were in U.S., it's not.

----- Original Message ----- 
From: "Vetrivel Adhimoolam" <vadhimoolam at gmail.com>
To: <loadstone at loadstone-gps.com>
Sent: Friday, October 09, 2009 2:57 AM
Subject: Re: [Loadstone] Possibility to ignore Cellid...


Hi,

Just forgive my ignorance. Cell towers in India mostly give us the location
information, but it is not so in the US. I tested with ATNT and T-Mobile,
but it's pretty much the same. So does it mean that there is BTS data
available for countries that show location information? Or does it simply
mean that cell towers in the US just transmit the code, but not the location
info in words?

Vetri.


----- Original Message ----- 
From: "Grzegorz Zlotowicz" <grzezlo at gmail.com>
To: <loadstone at loadstone-gps.com>
Sent: Thursday, October 08, 2009 8:15 PM
Subject: Re: [Loadstone] Possibility to ignore Cellid...


Hi,
A bts is an abbreviation from base transceiver station:
http://en.wikipedia.org/wiki/Base_Transceiver_Station
and means the same as cell site (i read it a minute before).
The sectoring of station is well described in the wikipedia, so i'll quote a
bit of their article about it, at the end of this message.
I'm not sure if the result processing is needed, simply clause "order by
cellid desc" should do the trick - if the query will return some non0 value,
it'll be the first row of result; if there is only description of cell with
cellid 0, it'll be the first.
Also a clause "limit 0,1" would possibly be nice, if the symbian dbms
handles it...
For the database of 25500 bts stations in Poland, each has a cellid greater
than 0; i suppose that it'll be no exception, but even if so, the whole
process stays well:
when you get from the phone an information that current cellid is 0, the
suggested query becomes a bit nonsense (cellid=0 or cellid=0), but nothing
bad happens.
When in the same exceptional bts with 0 cellid some user added the point
with cellid=1, the suggested query (cellid=1 or cellid=0) order by cellid
desc... will return proper answer...
Only result is that for such hipothetical bts the cellid0 will be the
default cell description for unknown cellids inside the lac, which is also
acceptable imho.
The separate database for bts data would be great, but from an other point
of view in actual state you can have small separate databases for separate
areas (cities), and querying them will be fast; having all bts data combined
into one huge db could generate a problem of long times of responses...

I don't know if there is official bts listing for some countries - it seems,
that all those data are experimental work of hobbyist...
A good news is, that rather for sure all this data is machine readable,
letting those people use a specially developed programs to hunt the new bts
station numbers (the Polish btsearch.pl site recomends few such
programs...).
Next good thing is, that from few sources there is a www.senderliste.de site
referred as a list of sites collecting the bts data - unfortunately in
german language, but with simple table (code of country and site link...).
I didn't explore given sites yet, so i don't know for sure anything about
them.
Greetings, Greg.

Quote from wikipedia:
Typically a BTS will have several transceivers (TRXs) which
allow it to serve several different frequencies and different sectors of the
cell
(in the case of sectorised base stations).
Sectoring
A cell is subdivided to a sure number of fields, every one of which "is
illuminated"
from an antenna directive (or panel), that is an antenna that "does not
illuminate"
in all the directions, but concentrates the flow of power within a
particular area
of the cell, known as sector. Every field can therefore be considered like
one new
cell. By using directional antennas, the co-channel interference is reduced.
A typical
structure is the trisector, also known as clover, in which there are 3
sectors, each
one served by separate antennas. Every sector has a separate direction of
tracking
of 120° with respect to the adjacent ones. If not sectorised, the cell will
be served
by an omnidirectional antenna, which radiates in all directions. Bisectored
cells
are also implemented with the antennas serving sectors of 180° separation to
one
another.
End of quote.

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