Question about running "lte_top_block_siso.py" ...

[jarodcs]

Hi there everybody, hope you are doing great! The following is a large question (forgive me in advance) regarding the use of the gr-lte lte_top_block_siso.py using as source files the ones generated by the openlte's applications:

1. LTEfilerecorder (file created: file_recorded.bin)
2. LTE_fdd_dlfilegen (file created: file_generated.bin)

Just to explain it briefly, LTE_file_recorder creates a file by recording it from the air interface, in other words, what it is being received from a real LTE base station through the air at a certain frequency and BW, this means that is included losses and multipath time disperssion, among others. On the other hand, LTE_fdd_dl_file_gen creates a file of a certain number of LTE frames. Both files can be checked wit the application LTE_fdd_dl_file_scan. More info here: https://github.com/osh/openlte

I generated both files:

1. LTEfilerecorder, earfcn = 3700

2. LTE_fdd_dlfilegen

3. Then both files through LTE_fdd_dlfilescan. Same cell_id=138

From what I know, I can tell that the recorded file (left side) has the same cell_id=138 as the generated file (rigth side), of course it has more info on the Scheduling info list because it is a real LTE base station I guess, and I think I even captured a M-TMSI which is some kind of S1-MME identifier. Again, I think. Well, both files show the expected data on the OpenLte applications.

Then, using each file as a source on the flowgraph lte_top_block_siso.py (on gnuradio) on different instances, it shows this:

Well, it seems to me that the file_generated.bin (rigth side) does not have the problem: ofdm_lte_remove_cp_cvc_0 OUT of sync!, because it is a "laboratory created file". On the other hand, the file_recorded.bin given that it has been recorded with an USRP device, probably it got overbuffered at some point and therefore it lost the time sync. Can anyone be so kind to point me where might be the problem that is causing this ofdm_lte_remove_cp_cvc_0 OUT of sync! on my -almost real world- test (left one).

Cheers Blinko

[a5552033]

hi,jarodcs I am sorry cannot solve this problem for you ,but I hope you could describe it clearly how did you solve the problem "import lte" .I know you have given the answers in #6 ,but as a Chinese,I cannot understand it. Hope your reply. Peggy

[jarodcs]

well Peggy, to be honest with you, it seems that I never had that problem installing the gr-lte package. I am using Kali Linux distribution which comes with a Metapackage called SDR that already includes Gnuradio and UHD (for USRP users) ... and therefore I did not need to install Gnuradio. Well, at that time (more beginner than now) seems that I did not know that I already had Gnuradio and I downloaded it and installed it from source ... which, I suppose, created another path for gnuradio on my system (remember that I already had it) ... I think that is why when I installed gr-lte, it could not find the gnuradio files properly. Once I realized that I already had gnuradio I uninstalled the one I installed from source and reboot my system, then I could installed gr-lte correctly by follwing the steps they describe on its git-hub page. That is all. SOrry coulnd help more. I am struggling with understanding the app, I hope you can solve it so maybe you can help me.

Cheers. Jarodcs

[a5552033]

@jarodcs thank u for your answer!Now I could understand it and I think we have different problems.I am using Ubuntu 14.04 lts,and I also could installed gr-lte,but I cannot import lte.I will try my best to solve this problem.If I make any new progress,I will tell u :-) can you tell me your frequently-used email?

[jarodcs]

@a5552033 sure, it is jarod.cs@gmail.com. write me there, hope I can help!

[ceren58]

Hi @jarodcs , have you solved your problem? I've got the same issue when I am using an USRP, if you have the answer to that I would be grateful