No signal output runnig oai-eNB LTE with LimeSDR mini

Projects LibreCellular
1

Hi everybody,

I am using LimeSDR mini (the old version) to run the LTE eNB from openairinterface5G. I followed the steps suggested in LimeSDR installation – 4G and 5G reference software and I am using the file LimeSDR_Mini_below_1p8GHz.ini as in trx-lms7002m/config-limeSDR/LimeSDR_Mini_below_1p8GHz.ini at master · myriadrf/trx-lms7002m · GitHub . It seems that LTE eNB runs OK as shown bellow, but there is not signal at LimeSDR mini output. Could someone help me to find what is wrong? Thanks, Sindi.

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[PHY] Required DLSCH mem size 4992 (bw scaling 2), dlsch->harq_processes[5] 0x7f5dca6d9040
[PHY] Required DLSCH mem size 4992 (bw scaling 2), dlsch->harq_processes[6] 0x7f5dca685040
[PHY] Required DLSCH mem size 4992 (bw scaling 2), dlsch->harq_processes[7] 0x7f5dca631040
[PHY] init_eNB_proc(inst:0) RC.nb_CC[inst]:1
[PHY] Initializing eNB processes instance:0 CC_id 0
[PHY] eNB->single_thread_flag:0
[UTIL] Creating thread L1 stats with affinity -1 and priority 1
[HW] [SCHED][eNB] eNB_thread_prach started on CPU 1, sched_policy = SCHED_FIFO , priority = 99, CPU Affinity= CPU_0 CPU_1 CPU_2 CPU_3 CPU_4 CPU_5 CPU_6 CPU_7
[HW] [SCHED][eNB] eNB_thread_prach_br started on CPU 0, sched_policy = SCHED_FIFO , priority = 99, CPU Affinity= CPU_0 CPU_1 CPU_2 CPU_3 CPU_4 CPU_5 CPU_6 CPU_7
waiting for sync (L1_stats_thread,-1/0x55b6081451c8,0x55b608742a20,0x55b608741c60)
[ENB_APP] ALL RUs ready - ALL eNBs ready
[ENB_APP] Sending sync to all threads
[MME_APP] Creating MME_APP eNB Task
got sync (L1_stats_thread)
[UTIL] Creating thread TASK_MME_APP with affinity -1 and priority 50
got sync (ru_thread)
Connecting to device: LimeSDR Mini, media=USB 3.0, module=FT601, addr=24607:1027, serial=1D751379EE2345
[ITTI] Created Posix thread TASK_MME_APP
[LIBCONFIG] MMEs.[0]: 1/1 parameters successfully set, (1 to default value)
[MCE_APP] Creating MCE_APP eNB Task
[UTIL] Creating thread TASK_MCE_APP with affinity -1 and priority 50
[ITTI] Created Posix thread TASK_MCE_APP
[ENB_APP] [MCE 0] MCE_app_register via M3AP for instance 0
[LIBCONFIG] MCEs.[0]: 1/1 parameters successfully set, (1 to default value)
[LIBCONFIG] MCEs.[0]: 1/1 parameters successfully set, (1 to default value)
Reference clock 40.00 MHz
[ENB_APP] TYPE TO TERMINATE
[LIBCONFIG] loader.enbscope: 2/2 parameters successfully set, (1 to default value)
shlib_path libenbscope.so
[LOADER] library libenbscope.so is not loaded: libenbscope.so: cannot open shared object file: No such file or directory
Set sample rate 15.360000 MHz
Set TX frequency 760.500000 MHz
RX LPF configured
Filter calibrated. Filter order-4th, filter bandwidth set to 15.36 MHz.Real pole 1st order filter set to 2.5 MHz. Preemphasis filter not active
TX LPF configured
Rx calibration finished
Tx calibration finished
SR: 15.360 MHz
SR: 15.360 MHz
[PHY] RU 0 rf device ready
[PHY] RU 0 Starting steady-state operation
[RLC] rlc_tick: discontinuity (expected 0.1, got 0.4)
[MAC] SCHED_MODE = 0

2

The blog post you used as a guide is just over 6 years old.

It might be worth asking in the OAI community. I’m not sure what the status of LimeSDR support is these days.

3

Hi Andrew,

Thanks for the reply. Yes, the config file is very old, but it is the only one that I found for LimeSDR mini. I will ask in the OAI community. Best regards, Sindi.

4

Hi Andrew,

Concerning this issue, I´d like let you know that I succeed to obtain the LTE signal at the output of the LimeSDR mini (for both versions). Basically, I did two things:

First: the parameter “att_tx” in config file is not attenuation, but a gain as mentioned in OAI and LimeSDR-Mini - #126 by dast . The best values for the parameter of RU for band 28 I found are as follows:

RUs = (

{

local_rf = “yes”

nb_tx = 1

nb_rx = 1

att_tx = 70; # (this is not attenuation, but a gain)

att_rx = 0;

bands = [28];

max_pdschReferenceSignalPower = -24;

max_rxgain = 110;

eNB_instances = [0];

}.

Second: despite the OAI eNodeB is operating below 1.8 GHz, the first time I turn on the LimeSDR mini, I need to use the config file: LimeSDR_Mini_above_1p8GHz.ini instead of LimeSDR_Mini_below_1p8GHz.ini . Once the LimeSDR mini started with config file above_1p8GHz , I can stop the eNodeB and change the config file to below_1p8GHz. But it is not necessary to make this change, since it works well with the above 1p8GHz config file despite the eNodeB is operating below 1.8 GHz. I don´t know why this happens and I would be very grateful if you or someone could explain this. I got the LimeSDR mini config files from https://github.com/myriadrf/trx-lms7002m/tree/master/config-limeSDR

Best regards, Sindi

1 Like
5

The INI files configure all sorts of things. You can load them into LimeSuiteGUI to view the settings and could compare what is set differently with different INI files. Though I did think that the SDR would be reset when it is opened and closed by applications, hence parameters set by INI files would be reset by OAI starting. But maybe it’s not all settings. Tagging @Zack as he is likely to know.

6

Hi Andrew,

Ok, I will try to view the settings by using LimeSuiteGui. Thank you, Sindi.