What is the format of "-i input_file"?

[novitoll]

~I dont see that the code is able to receive IQ from CSV or binary (raw floats or doubles) file.~ ~Could you please provide the sample code or the code that needs to be changed to read IQ stream from the input file?~

I see there is "input_file_name" arg, what is the format of such as file? Is it raw floats of IQ or doubles? https://github.com/SysSec-KAIST/LTESniffer/blob/main/src/src/LTESniffer_Core.cc#L240

[novitoll]

I have following CSV (captured from bladeRF):

-0.2041015625,-0.0791015625
-0.05224609375,-0.0751953125
0.06640625,-0.1298828125
0.09326171875,0.02294921875
0.1474609375,-0.05859375
...

and I am using this Python script to convert each IQ to float bytes, as in srsRAN it's read as

if (srsran_filesource_init(&q->file_source, file_name, SRSRAN_COMPLEX_FLOAT_BIN)) {

import sys
import struct

f_csv = sys.argv[1]

with open(f_csv, "r") as f:
    lines = f.readlines()

with open("data.bin", "wb+") as f_w:
    for line in lines:
        i, q = line.split(',')

        i = struct.pack("<f", float(i))
        q = struct.pack("<f", float(q))

        f_w.write(q)
        f_w.write(i)

and no data is decoded (I've checked with -v, and MIB is not decoded neither). @hdtuanss , Could you please suggest?

$ ./src/LTESniffer -A 1 -f 1870M -m 0 -P 1 -p 100 -c 151 -i ~/Downloads/data.bin

LTESniffer

Sun_Jun__4_15.07.35_2023.
Creating Phy
Creating 4 Worker threads 
[15:07:36] Processed 1000/1000 subframes
[15:07:36] Processed 1000/1000 subframes
[15:07:37] Processed 1000/1000 subframes
[15:07:37] Processed 1000/1000 subframes
[15:07:37] Processed 1000/1000 subframes
[15:07:38] Processed 1000/1000 subframes
[15:07:38] Processed 1000/1000 subframes
[15:07:38] Processed 1000/1000 subframes
[15:07:39] Processed 1000/1000 subframes
[15:07:39] Processed 1000/1000 subframes
--------------------------------------------------------------------------------------------------------
Num  RNTI     Table       Active   New TX   ReTX     Success  HARQ     Normal   W_MIMO   W_pinfor Other    
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
Num  RNTI     Table       Active   New TX   ReTX     Success  HARQ     Normal   W_MIMO   W_pinfor Other    
--------------------------------------------------------------------------------------------------------
[256Tracking] Total: 0 RNTIs are 64QAM table, 0 RNTIs are 256QAM table, 0 RNTIs are Unknown 

[15:07:40] Processed 1000/1000 subframes
[15:07:40] Processed 1000/1000 subframes
[15:07:40] Processed 1000/1000 subframes
[15:07:41] Processed 1000/1000 subframes
[15:07:41] Processed 1000/1000 subframes
[15:07:41] Processed 1000/1000 subframes
[15:07:42] Processed 1000/1000 subframes
[15:07:42] Processed 1000/1000 subframes
[15:07:42] Processed 1000/1000 subframes
[15:07:43] Processed 1000/1000 subframes

[hdtuanss]

Hi, option -I is for inputting an IQ file that contains aligned subframes and starts with a subframe with index 0 (containing MIB). The I/Q file can be generated using the FalconCaptureProbe tool from FALCON (https://github.com/falkenber9/falcon). Just so you know, this tool only supports capturing subframes using 1 antenna. In your case, your I/Q sample file might not contain aligned subframes with a subframe index 0 at the start, so LTESniffer cannot decode your I/Q file successfully. Also, this option is used for only testing, and it does not support full functionalities as direct decoding from the SDR of LTESniffer. I recommend you modify the code of FalconCaptureProbe tool from FALCON for capturing with 2 RX antennas and then decode by LTESniffer. Thanks