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BCCH data uncovered

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(@trewmte)
Posts: 1877
Noble Member
Topic starter
 

The data found in the elementary file broadcast control channel (EFBCCH) 7F206F74/7F216F74 can provide useful data relating to a geographical radio area when combined with location area information data.

Method for translating BCCH information data. The question is, is the translation below to find the BCCH frequencies correct and what have I not mentioned below? You will need copies of GSM11.11, GSM03.03, GSM04.08 as well as understanding coding schemes.

FIGURE 1 What the Standard states

FIGURE 2 What that means

FIGURE 3 Harvested data from a Orange SIM Card read

FIGURE 4 Translating the hex output to binary

FIGURE 5 Converting to decimal digits which translates again and corresponds to GSM assigned uplink/downlink frequencies
BCCH Frequencies (ARFCN)
761 765 766 774 781 782 786 787 789 790 797 799 801 803 806 813 816 825 828 829 838 846 847 849 869

FIGURE 6 Corroborating the conversion using another tool

 
Posted : 13/09/2009 7:20 pm
bigjon
(@bigjon)
Posts: 159
Estimable Member
 

Trew, without the gsm docs can i have a stab at the fact i cannot see the access class here, i know i should be able to find refrerence to this in BCCH

 
Posted : 14/09/2009 3:12 pm
(@trewmte)
Posts: 1877
Noble Member
Topic starter
 

OK… EFBCCH doesn't contain access class numbers which can be found in EFACC in SIM. The BCCH numbers discussed above are relevant only to those radio frequencies from the neighbouring cells identified by their ARFCN (absolute radio frequency control number).

Whilst the entire BCCH frame of data identifies access classes in them that can be used, as mentioned the EFBCCH above only relates to ARFCN.

So the points you make would not deal with the points I have made above. And yes, I am afraid so, you will need to obtain the standards - which are free by the way.

 
Posted : 14/09/2009 3:24 pm
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