[srslte-users] Please help with srsENB DL problems!

Tue Oct 31 14:55:03 UTC 2017

Hi Ilshat,

The CQI reported by the UE is very log. Set tx_gain=89 and rx_gain=40.
Position the antenna vertically (perpendicular to the floor) and the RX
antenna horizontally (parallel to the floor). What HW are you using? B210?

On Tue, 31 Oct 2017 at 00:25 Ilshat Shaidullin <ilshat.desu at gmail.com>
wrote:

> Hello, Ismael!
>
> I'm sending log files. I set tx_gain = 89, rx_gain  = 70.
> After UE had attached to network I used app (Ookla Speedtest) for testing
> its speed.
>
> When phone was about 1 meter from USRP it reached 5.74 Mbps DL and 4.84
> Mbps UL.
> When phone was about 4 meters from USRP it reached 0.57 Mbps DL and 5.13
> Mbps UL.
>
>
> Best,
> Ilshat
> 
>  4meters.log
> <https://drive.google.com/file/d/0B-Vw2qvzCYviVVJDblVTNVIxM1E/view?usp=drive_web>
> 
>  1meter.log
> <https://drive.google.com/file/d/0B-Vw2qvzCYvibHVHMnpzYWc1OXc/view?usp=drive_web>
> 
>
> 2017-10-31 3:51 GMT+03:00 Ismael Gomez <
> ismael.gomez at softwareradiosystems.com>:
>
>> also, can you try increasing the TX power? (Maximum is tx_gain=89 in
>> enb.conf if you use a B2x0 USRP)
>>
>> On Mon, 30 Oct 2017 at 08:45 Ismael Gomez <
>> ismael.gomez at softwareradiosystems.com> wrote:
>>
>>> Can you send enb.log too? (log level info is enough)
>>>
>>>
>>> On Mon, 30 Oct 2017 at 07:04 Ilshat Shaidullin <ilshat.desu at gmail.com>
>>> wrote:
>>>
>>>> I forgot to attach console trace in the last e-mail. Maybe it will help
>>>> to figure out what's the problem.
>>>>
>>>> CASE 1 -->  UE is about 1-2 meters from USRP.
>>>>
>>>> When I test DL speed, I get this:
>>>> ------DL-------------------UL----------------
>>>> rnti   mcs   brate   bler  snr  phr  turbo  mcs  brate   bler
>>>> 46     16   7.2M   0.0%    20    40   1.0    12   211k   0.0%
>>>>
>>>> When I test UL speed, I get this:
>>>> ------DL-------------------UL----------------
>>>> rnti   mcs   brate   bler  snr  phr  turbo  mcs  brate   bler
>>>> 46    6.0   542k   0.0%    22    39   1.0    16   7.6M   0.0%
>>>>
>>>> Both DL and UL speeds are good.
>>>>
>>>>
>>>> CASE 2 --> UE is further than 2 meters from USRP.
>>>>
>>>> When I test DL speed, I get this:
>>>> ------DL-------------------UL----------------
>>>> rnti   mcs   brate   bler  snr  phr  turbo  mcs  brate   bler
>>>> 46     13   733k    46%    15    34   1.0    11   128k   0.0%
>>>>
>>>> When I test UL speed, I get this:
>>>> ------DL-------------------UL----------------
>>>> rnti   mcs   brate   bler  snr  phr  turbo  mcs  brate   bler
>>>> 46    4.3   274k   1.7%    16    33   1.0    13   6.0M   0.0%
>>>>
>>>> UL speed is good (only small decrease compared to the previous case).
>>>> DL speed is very low (large decrease of speed compared to the previous
>>>> case) and BLER is high.
>>>>
>>>>
>>>> Best,
>>>> Ilshat
>>>>
>>>> 2017-10-30 14:02 GMT+03:00 Ilshat Shaidullin <ilshat.desu at gmail.com>:
>>>>
>>>>> Hello, Ismael!
>>>>>
>>>>> Thank you for replying me.
>>>>>
>>>>> I downloaded srsENB configuration files from repository, but nothing
>>>>> changed. As only DL speed suffers when distance is larger than 2 meters, it
>>>>> looks like that problem is caused by RS (Reference Signal) power. Maybe I
>>>>> am wrong.
>>>>>
>>>>> I looked through the code and couldn't find out how pdsch-ConfigCommon
>>>>> from SIB2 (information about RS power) is used.
>>>>> I see that phy object is initialized with phy_cfg_t structure. But I
>>>>> don't see how pdsch_cnfg from phy_cfg_t structure field is used.
>>>>> In srslte (enb_dl.c, refsignal_dl.c) I couldn't find how RS power can
>>>>> be changed.
>>>>>
>>>>>
>>>>> Best,
>>>>> Ilshat
>>>>>
>>>>> 2017-10-27 19:40 GMT+03:00 Ismael Gomez <
>>>>> ismael.gomez at softwareradiosystems.com>:
>>>>>
>>>>>> Hi Ilshat,
>>>>>>
>>>>>> Make sure your reference signal power and pusch/pucch power settings
>>>>>> are correct in sib.conf
>>>>>>
>>>>>> Regards
>>>>>>
>>>>>> El vie., 27 oct. 2017 9:33, Ilshat Shaidullin <ilshat.desu at gmail.com>
>>>>>> escribió:
>>>>>>
>>>>>>> Hello!
>>>>>>>
>>>>>>> I have a question about 2 DL problems in srsENB. I use the following
>>>>>>> configuration:
>>>>>>> - USRP B210
>>>>>>> - 25 PRB bandwidth
>>>>>>> - Max DL MCS Limit 16.
>>>>>>>
>>>>>>> When phone is within about 1-2 meters from USRP, everything works
>>>>>>> great. UE reaches 6.7 Mbps in DL and 4-5 Mbps in UL. But, if UE is further
>>>>>>> than 2 meters from USRP, DL speed is very low (0.1-0.3 Mbps) although
>>>>>>> signal strength is good (-77 dBm) and UL speed is high (4 Mbps). And if UE
>>>>>>> is about 6-7 meters from USRP it can't stay attached for a long period. It
>>>>>>> disconnects and attaches to commercial eNB,
>>>>>>>
>>>>>>> Also there is a problem, when UE tries to attach and the distance
>>>>>>> between UE and USRP is about 6-7 meters. Signal strength is about -80 dBm
>>>>>>> and is the best among other commercial eNB.  Phone performs many RA
>>>>>>> procedures, but they fail. But phone can easily attach to commercial eNB
>>>>>>> with signal strength -86 dBM and which is situated quite far from our
>>>>>>> office.
>>>>>>>
>>>>>>> I have a feeling that the same thing causes these two troubles.
>>>>>>>
>>>>>>> Please, help me to figure out what is wrong.
>>>>>>>
>>>>>>> Best,
>>>>>>> Ilshat
>>>>>>> _______________________________________________
>>>>>>> srslte-users mailing list
>>>>>>> srslte-users at lists.softwareradiosystems.com
>>>>>>> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
>>>>>>>
>>>>>>
>>>>>
>>>>
>
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