[srsran-users] LTE: How to decode DL-SCH data when C-RNTI and DL-SCH Settings are unknown

[Sabyrzhan Tasbolatov]

Hello,

Trying to understand 4G/LTE decoding process on DL-SCH channel using Matlab.

I'm reading SRSRan code pdsch.c as well as the reference, though a bit not
clear to me.
So asking here as you've might already done this in C, I'm doing it in
Matlab.

Question:

I'm following this example
https://www.mathworks.com/help/lte/ug/cell-search-mib-and-sib1-recovery.html


*I can decode SI-RNTI SIB1 message on every even SFN and subframe # 5.How
to decode DL-SCH when we dont know C-RNTI type (where user plane is) RNTI
number for subframes # 0 to #9?*

I'm posting here question from my Matlab post as well:

Now what is the procedure when we want to decode other subframes from 0 to
9. How can we do PDCCH blind search when we dont know C-RNTI? This can be
UESpecific search, then we need to bruteforce from 0x000B to 0xFFF3 all
possible RNTIs and see DCI candidates and try to DL-SCH decode subframe
OFDM demod rxGrid with that, right? But this is too slow, like 17 mins per
1 subframe in 20MHz BW.
SIB1 is decoded with PDSCH config where Modulation is 'QPSK'. (set in
hPDSCHConfiguration function explicitly). Does it mean that all other
subframes should use the same PDSCH config as well?

I've asked the question in Matlab. Duplicating
https://www.mathworks.com/matlabcentral/answers/1779905-how-to-decode-dl-sch-data-when-c-rnti-and-dl-sch-settings-are-unknown

-- 
         Sabr
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