[srslte-users] how to decode SIB 5 with srslte?
ALEJANDRO BLANCO PIZARRO
100283180 at alumnos.uc3m.es
Mon Feb 12 09:39:02 UTC 2018
Hi Erik,
There are two parameters of your interest. The first one is the periodicity:
<SchedulingInfo>
<si-Periodicity>
<rf32/>
</si-Periodicity>
<sib-MappingInfo>
<sibType5/>
</sib-MappingInfo>
</SchedulingInfo>
In this case, the sib5 has a periodicity of 32, this means that the message
is going to be sent each 320 ms.
The other parameter is the window:
<si-WindowLength>
<ms40/>
</si-WindowLength>
I am not going to explain how is the process of calculating the sib
scheduling, but you can check it here
http://www.sharetechnote.com/html/BasicProcedure_LTE_SIB_Scheduling.html.
My piece of advice is to start with an easy task, for examples: you should
try to change the line (my previous email) if
((srslte_ue_sync_get_sfidx(&ue_sync)
== 5 && (sfn%repetition_sfn)== 8)) to a loop changing the frame number and
the subframe id. With the loop, you are going to access to the payload of
every sib message, so try to see what is the periodicity of each message
and how was scheduled.
Tell me if you need further information.
Best regards,
Alejandro
2018-02-12 4:06 GMT+01:00 Access Lab <lab.accesssolution at gmail.com>:
> Hi Alejandro,
>
> Thanks for the information, if you don't mind, i would like to ask some
> technical question regarding the SIB 5 decoding.
> From your previous email, you said that we can use the scheduling
> -info-list in the field of SIB1 message.
>
> I'm using an online decoder from www.marben-products.com, and here is the
> result of SIB 1 decoding:
>
> <BCCH-DL-SCH-Message>
> <message>
> <c1>
> <systemInformationBlockType1>
> <cellAccessRelatedInfo>
> <plmn-IdentityList>
> <PLMN-IdentityInfo>
> <plmn-Identity>
> <mcc>
> <MCC-MNC-Digit>5</MCC-MNC-Digit>
> <MCC-MNC-Digit>1</MCC-MNC-Digit>
> <MCC-MNC-Digit>0</MCC-MNC-Digit>
> </mcc>
> <mnc>
> <MCC-MNC-Digit>1</MCC-MNC-Digit>
> <MCC-MNC-Digit>1</MCC-MNC-Digit>
> </mnc>
> </plmn-Identity>
> <cellReservedForOperatorUse>
> <notReserved/>
> </cellReservedForOperatorUse>
> </PLMN-IdentityInfo>
> </plmn-IdentityList>
> <trackingAreaCode>1100011100111101</trackingAreaCode>
> <cellIdentity>0111110010100010001000000100</cellIdentity>
> <cellBarred>
> <notBarred/>
> </cellBarred>
> <intraFreqReselection>
> <allowed/>
> </intraFreqReselection>
> <csg-Indication>
> <false/>
> </csg-Indication>
> </cellAccessRelatedInfo>
> <cellSelectionInfo>
> <q-RxLevMin>-64</q-RxLevMin>
> </cellSelectionInfo>
> <freqBandIndicator>3</freqBandIndicator>
> <schedulingInfoList>
> <SchedulingInfo>
> <si-Periodicity>
> <rf16/>
> </si-Periodicity>
> <sib-MappingInfo>
> <sibType3/>
> </sib-MappingInfo>
> </SchedulingInfo>
> <SchedulingInfo>
> <si-Periodicity>
> <rf32/>
> </si-Periodicity>
> <sib-MappingInfo>
> <sibType5/>
> </sib-MappingInfo>
> </SchedulingInfo>
> <SchedulingInfo>
> <si-Periodicity>
> <rf64/>
> </si-Periodicity>
> <sib-MappingInfo>
> <sibType6/>
> </sib-MappingInfo>
> </SchedulingInfo>
> </schedulingInfoList>
> <si-WindowLength>
> <ms40/>
> </si-WindowLength>
> <systemInfoValueTag>7</systemInfoValueTag>
> </systemInformationBlockType1>
> </c1>
> </message>
> </BCCH-DL-SCH-Message>
>
> 18 bytes decoded.
> * DECODING SUCCESSFUL *
>
> I can see that there is some information regarding the
> scheduling-info-list for SIB 5, but what is the meaning of the above
> information?
> I'm sorry if this question sounds very basic and technical, because i'm
> very new with this topic.
>
> Thanks for your information,
>
> Regards,
> Erik
>
> 2018-02-07 16:42 GMT+07:00 ALEJANDRO BLANCO PIZARRO <
> 100283180 at alumnos.uc3m.es>:
>
>> Hi Erik, srsLTE community,
>>
>> It is possible to get the payload of SIB5 with srsLTE by
>> cell_measurement.c. As you know, the SIB1 message is scheduled with a
>> periodicity of 80 ms and conveyed on the subframe index equal to 5.
>> Unfortunately, the other SIB messages don't have a fixed secheduling. The
>> information in relation with the scheduling is in the scheduling
>> -info-list, this is a field of SIB1, so now you are able to know it if you
>> decode the SIB1 message
>>
>> The cell_measurement is programmed only to capture SIB1 messages,
>> therefore you will need to change part of the code. The line of your
>> interest is this one: if ((srslte_ue_sync_get_sfidx(&ue_sync) == 5 &&
>> (sfn%repetition_sfn)== 8)).
>>
>> Finally, if you know how SIB5 is scheduled, you only have to change the
>> values 5 and 8 for the correct values.
>>
>> Best regards,
>> Alejandro
>>
>> 2018-02-07 8:32 GMT+01:00 Access Lab <lab.accesssolution at gmail.com>:
>>
>>> Hi List,
>>>
>>> Does anyone know or can give some info regarding the above question?
>>>
>>> Previously i was able to decode SIB 1 message by using sib payload from
>>> cell-measurement feature, but i still couldn't get any info regarding SIB 5.
>>>
>>> Could someone give some info or explanation?
>>>
>>> Thanks & regards,
>>>
>>> Erik
>>>
>>>
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>
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