[srslte-users] pdcch_file_test

Tue May 3 01:49:38 UTC 2016

Hi Ismael,

I have another question
I was looking into pdcch.c in the descrambling process
I know that the descrambling sequence should depend on the sub-frame number
and the cell-ID using the expression (c_init = floor(ns/2)*2^9 + cell-ID)
Where is this accounted for in the codes ?

Also, I have one more observation, we have known from the cellular provider
in our province that they have LTE Rel-11 deployed. Will that be a problem
since srs-LTE supports LTE Rel-8 ?
I guess to force backward compatibility, LTE Rel-11 should support LTE
Rel-8 as well. Am I right ?

Thank you,

On Mon, May 2, 2016 at 12:29 AM, amr adel <amr.adelnasr at gmail.com> wrote:

> Hi Ismael,
>
> Yeah, I am using the latest version of srs-LTE
> I was comparing the decoding results of both srs-LTE and openlte for a
> certain sub-frame (the crc result) and they both gave different values !!
> If you like I can send you the LTE signal file that I have to test it
> yourself. It's around 25 MB (9 frames recorded at 30.72 MSps)
> Thank you so much,
>
> On Fri, Apr 29, 2016 at 2:44 AM, Ismael Gomez <
> ismael.gomez at softwareradiosystems.com> wrote:
>
>> HI Amr,
>>
>> Are you using the last version 1.2? In 1.1 there was a bug in PDCCH
>> decoding for some cell IDs.
>>
>> Regarding the CFI, this program you are using is a test program, designed
>> to test the functionality of a small part of the system. Therefore the CFI
>> is assumed to be constant. What you can do it modify it to decode the CFI
>> dynamically every subframe.
>>
>> cheers
>>
>> On Thu, 28 Apr 2016 at 05:12 amr adel <amr.adelnasr at gmail.com> wrote:
>>
>>> Hi Ismael,
>>>
>>> I have a problem with the pdcch_file_test
>>>
>>> I am trying to decode the dci1A message using SIRNTI
>>> Using OpenLTE, I verified that this message exists on even frames ,
>>> subframe 5
>>> However, I failed when I used the pdcch_file_test
>>>
>>> I have an LTE signal with 30.72 MSps that is saved in a binary file,
>>> with a total of 9 frames captured --> 90 sub-frames
>>> I was able to run pbch_file_test and pcfich_file_test successfully with
>>> that file (I verified the values with OpenLTE)
>>>
>>> Also, one more issue with pdcch_file_test is that it assumes constant
>>> cfi value for all subframes which is not true. I tried modifying that in
>>> the code so that it changes the cfi value with each sub-frame but the code
>>> failed to decode any dci1A messages (crc does not pass i.e. crc != SIRNTI)
>>>
>>> Any ideas what could be wrong ??
>>>
>>> This is a sample output that I got (I have modified the way the output
>>> is displayed for debugging purposes)
>>>
>>> ==============================================================
>>>
>>> [INFO]:  Reading 30720 samples from sub-frame 4 frame 2 with cfi value 1
>>> Extracting LLRs: E: 1440, SF: 4, CFI: 1
>>> [INFO]:  Initializing common search space for SI-RNTI
>>> Common SS Candidate 0: nCCE: 0, L: 3
>>> Common SS Candidate 1: nCCE: 8, L: 3
>>> Common SS Candidate 2: nCCE: 0, L: 2
>>> Common SS Candidate 3: nCCE: 4, L: 2
>>> Common SS Candidate 4: nCCE: 8, L: 2
>>> Common SS Candidate 5: nCCE: 12, L: 2
>>> [INFO]:  Initiated 6 candidate(s) in the Common search space
>>> Skipping DCI:  nCCE=0, L=3, msg_len=28, mean=0.317454 crc 0
>>> Skipping DCI:  nCCE=8, L=3, msg_len=28, mean=0.356984 crc 0
>>> Skipping DCI:  nCCE=0, L=2, msg_len=28, mean=0.328331 crc 0
>>> Skipping DCI:  nCCE=4, L=2, msg_len=28, mean=0.306578 crc 0
>>> Skipping DCI:  nCCE=8, L=2, msg_len=28, mean=0.369074 crc 0
>>> Skipping DCI:  nCCE=12, L=2, msg_len=28, mean=0.344894 crc 0
>>>
>>>
>>> [INFO]:  Reading 30720 samples from sub-frame 5 frame 2 with cfi value 1
>>> Extracting LLRs: E: 1440, SF: 5, CFI: 1
>>> [INFO]:  Initializing common search space for SI-RNTI
>>> Common SS Candidate 0: nCCE: 0, L: 3
>>> Common SS Candidate 1: nCCE: 8, L: 3
>>> Common SS Candidate 2: nCCE: 0, L: 2
>>> Common SS Candidate 3: nCCE: 4, L: 2
>>> Common SS Candidate 4: nCCE: 8, L: 2
>>> Common SS Candidate 5: nCCE: 12, L: 2
>>> [INFO]:  Initiated 6 candidate(s) in the Common search space
>>> Decoded DCI: nCCE=0, L=3, msg_len=28, mean=0.839736, crc_rem=0xa76c crc
>>> 42860
>>> Decoded DCI: nCCE=8, L=3, msg_len=28, mean=0.790758, crc_rem=0x490d crc
>>> 18701
>>> Decoded DCI: nCCE=0, L=2, msg_len=28, mean=0.885439, crc_rem=0x38a3 crc
>>> 14499
>>> Decoded DCI: nCCE=4, L=2, msg_len=28, mean=0.794033, crc_rem=0x35b1 crc
>>> 13745
>>> Decoded DCI: nCCE=8, L=2, msg_len=28, mean=0.751408, crc_rem=0xe973 crc
>>> 59763
>>> Decoded DCI: nCCE=12, L=2, msg_len=28, mean=0.830108, crc_rem=0x22d9 crc
>>> 8921
>>>
>>>
>>> [INFO]:  Reading 30720 samples from sub-frame 6 frame 2 with cfi value 1
>>> Extracting LLRs: E: 1440, SF: 6, CFI: 1
>>> [INFO]:  Initializing common search space for SI-RNTI
>>> Common SS Candidate 0: nCCE: 0, L: 3
>>> Common SS Candidate 1: nCCE: 8, L: 3
>>> Common SS Candidate 2: nCCE: 0, L: 2
>>> Common SS Candidate 3: nCCE: 4, L: 2
>>> Common SS Candidate 4: nCCE: 8, L: 2
>>> Common SS Candidate 5: nCCE: 12, L: 2
>>> [INFO]:  Initiated 6 candidate(s) in the Common search space
>>> Skipping DCI:  nCCE=0, L=3, msg_len=28, mean=0.417290 crc 0
>>> Skipping DCI:  nCCE=8, L=3, msg_len=28, mean=0.400091 crc 0
>>> Skipping DCI:  nCCE=0, L=2, msg_len=28, mean=0.427990 crc 0
>>> Skipping DCI:  nCCE=4, L=2, msg_len=28, mean=0.406590 crc 0
>>> Skipping DCI:  nCCE=8, L=2, msg_len=28, mean=0.374190 crc 0
>>> Skipping DCI:  nCCE=12, L=2, msg_len=28, mean=0.425992 crc 0
>>> ==============================================================
>>>
>>> On sub-frame 5, frame 2, Openlte indicated that there is a dci1A message
>>> Thank you,
>>>
>>> --
>>> Amr Abdelnasser
>>>
>>>
>
>
> --
> Amr Abdelnasser
>
>

-- 
Amr Abdelnasser
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