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

[Ismael Gomez]

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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