[srslte-users] Question about decoding SIBs messages

[Edward Johnson]

Dear srsLTE community,
first of all, I would like to thanks you about your excellent work with
srsLTE, it's not easy and I really appreciate it.
I would like to share with you a problem I founded when I try to modify
"cell_measurement.c" example for find and decoding others SIB messages.
My scope was to find and decode all SIBs messages I can from a nearby LTE
cell. So I start to play with the example and I was successfully able to
find and decode SIB2, SIB3 and SIB6.
According with my SIB1's decoder ( aka, a little modification of yours in
liblte_rrc.h/c) and the online decoder Marben, this cell should be
transmits SIB nr 2,3,5,6,7,8 with the following configuration:
<schedulingInfoList>
  <SchedulingInfo>
    <si-Periodicity>
      <rf8/>
    </si-Periodicity>
    <sib-MappingInfo/>
  </SchedulingInfo>
  <SchedulingInfo>
    <si-Periodicity>
      <rf16/>
    </si-Periodicity>
    <sib-MappingInfo>
      <sibType3/>
      <sibType5/>
    </sib-MappingInfo>
  </SchedulingInfo>
  <SchedulingInfo>
    <si-Periodicity>
      <rf32/>
    </si-Periodicity>
    <sib-MappingInfo>
      <sibType6/>
      <sibType7/>
      <sibType8/>
    </sib-MappingInfo>
  </SchedulingInfo>
</schedulingInfoList>
<si-WindowLength>
  <ms20/>
</si-WindowLength>

>From that, I calculate the frame number and periodicity of transmission for
all the SIBs, modify cell_measurement and I was able to find a lots of SIBs
messages but not all the ones that are supposed to be transmitted: I
receive sib1, sib2, sib3 and sib6 messages but I never see sib 5,7 and 8
ones.
In the code, I just modify the "if" checks for SIB1 in cell_measurement
with that piece of code:


*if ((srslte_ue_sync_get_sfidx(&ue_sync) == subframe     && (sfn %
periodicity) == (x/ 10))*

where:
x = (idxOfSchedulingInfoList - 1 )* siWindowLength;
subframe = x % 10;
periodicity = fr8/fr16/rf32 ( according with the SIB I'm looking at the
moment);
E.g. for the values attached above, I've the following situation:
SIB 3 - Period: 16; subframe: 0; X: 0;
SIB 5 - Period: 16; subframe: 1; X: 20;
SIB 6 - Period: 32; subframe: 2; X: 40;
SIB 7 - Period: 32; subframe: 3; X: 60;
SIB 8 - Period: 32; subframe: 4; X: 80;

There is something I misunderstand? Or I have to miss something?

Thanks in advance for patience and time,
Edward
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