[srslte-users] What is the maximum channel delay (with channel emulator)?

[Justin Tallon]

Hey bong,

Just looked at your logs and conf there.

If you want to do long-range capable RACHes you need to set the size of
your cell to be larger.

This is controlled by setting the zeroCorrelationZoneConfig in the sib.conf.

The largest cell size setting is zeroCorrelationZoneConfig=0 which gives
you a cell of 100km roughly.

This way you can tolerate much later PRACH messages.

Hope this helps!
Justin
____
Justin Tallon Ph.D.

Software Radio Systems (SRS)
http://www.softwareradiosystems.com

+353-86-067-0753 | justin.tallon at softwareradiosystems.com


On Thu, Dec 3, 2020 at 6:47 AM Bong Ho Kim <us.bhkim at gmail.com> wrote:

> Hi Justin,
>
> I wonder if you had a chance to take a look at the long and have any
> suggestions for me to resolve the issue on the RACH process with a long
> channel delay.
>
> Thanks in advance,
> Brian
>
>
> On Wed, Nov 25, 2020 at 4:43 AM Bong Ho Kim <us.bhkim at gmail.com> wrote:
>
>> Hi Justin,
>>
>> Here is the log files with "log.all_level = info" for both eNB and UE.
>>
>>
>> https://drive.google.com/file/d/1UiJkzQBLqbKcMemYvpSVkNHVzazNMVoX/view?usp=sharing
>>
>> Thank you very much for looking into this for me.
>>
>> Brian
>>
>>
>> On Wed, Nov 25, 2020 at 3:26 AM Justin Tallon <
>> justin.tallon at softwareradiosystems.com> wrote:
>>
>>> Hey Brian,
>>>
>>> Can you repeat this test with the log level set to "info" in both the
>>> eNodeB and the UE?
>>> log.all_level = info
>>>
>>> Regards,
>>> Justin
>>> ____
>>> Justin Tallon Ph.D.
>>>
>>> Software Radio Systems (SRS)
>>> http://www.softwareradiosystems.com
>>>
>>> +353-86-067-0753 | justin.tallon at softwareradiosystems.com
>>>
>>>
>>> On Tue, Nov 24, 2020 at 6:29 PM Bong Ho Kim <us.bhkim at gmail.com> wrote:
>>>
>>>> Hi Justin,
>>>>
>>>> I am sorry that the file attachment seems not allowed.
>>>> Here is the link to the log files.
>>>>
>>>>
>>>> https://drive.google.com/file/d/1Vs7jBvOX2cqUdmMmfOv5fLnFa8vpSe-q/view?usp=sharing
>>>>
>>>> Thanks again,
>>>> Brian
>>>>
>>>> On Tue, Nov 24, 2020 at 12:05 PM Bong Ho Kim <us.bhkim at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi Justin,
>>>>>
>>>>> Thanks for the quick response.
>>>>> With your help, I have updated the enb.conf
>>>>>      max_prach_offset_us  = 200
>>>>>
>>>>> both [channel.dl.delay] and  [channel.ul.delay] in the enb.conf file
>>>>>      enable        = true
>>>>>      period_s      = 3600
>>>>>      init_time_s   = 0
>>>>>      maximum_us    = 30
>>>>>      minimum_us    = 30
>>>>>
>>>>> The RACH process failed again.
>>>>> So I also tried the channel delay in the ue.conf (at the UE PC), but
>>>>> the result is the same.
>>>>> The ue.log indicates the following message, but in the sib.conf the
>>>>> response window size is set to 10ms (ra_resp_win_size = 10;  // in ms)
>>>>>       [MAC ] [E] [  394] RA response not received within the response
>>>>> window
>>>>>
>>>>> The two PCs I have set up for (eNB+EPC) and (UE) are directly
>>>>> connected using an ethernet cable.
>>>>> I think not, but might the physical delay between two PCs have
>>>>> affected it?
>>>>>
>>>>> To have more of your help I have attached (log.tar.gz) the log, pcap,
>>>>> and config files at the UE and ENB sides.
>>>>>
>>>>> Thank you,
>>>>> Brian
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Nov 24, 2020 at 5:05 AM Justin Tallon <
>>>>> justin.tallon at softwareradiosystems.com> wrote:
>>>>>
>>>>>> Hey,
>>>>>>
>>>>>> You need to increase max_prach_offset_us in the enodeb conf.
>>>>>>
>>>>>> Regards,
>>>>>> Justin
>>>>>> ____
>>>>>> Justin Tallon Ph.D.
>>>>>>
>>>>>> Software Radio Systems (SRS)
>>>>>> http://www.softwareradiosystems.com
>>>>>>
>>>>>> +353-86-067-0753 | justin.tallon at softwareradiosystems.com
>>>>>>
>>>>>>
>>>>>> On Tue, Nov 24, 2020 at 10:27 AM Bong Ho Kim <us.bhkim at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Dear srsLTE team,
>>>>>>>
>>>>>>> I have installed srsLTE Release 20.04.2, and the UE is attached to
>>>>>>> the srsLTE and can ping to the network when the channel emulator is
>>>>>>> disabled or channel delay is very small (i.e. 10 usec)
>>>>>>>
>>>>>>> But, I am trying to use about 100 usec delay for DL and 100 msec
>>>>>>> delay for UL using the "channel delay" configuration at eNB.
>>>>>>> So I updated the eNB side config file like below.
>>>>>>>
>>>>>>> *[channel.dl.delay]*
>>>>>>> enable = true
>>>>>>> period_s = 3600
>>>>>>> init_time_s = 0
>>>>>>> maximum_us = 100
>>>>>>> minimum_us = 100
>>>>>>>
>>>>>>> *[channel.ul.delay]*
>>>>>>> enable = true
>>>>>>> period_s = 3600
>>>>>>> init_time_s = 0
>>>>>>> maximum_us = 100
>>>>>>> minimum_us = 100
>>>>>>>
>>>>>>> Once channel delay is added ( RTT= 200 usec), the RACH process has
>>>>>>> failed.
>>>>>>> I believe that a 200 usec delay should be handled through the Timing
>>>>>>> Advance bits (11-bit) in the RAR message.
>>>>>>>
>>>>>>> Would you let me know the maximum channel delay that can be used in
>>>>>>> the srsLTE configuration if it was different from the standard?
>>>>>>>
>>>>>>> Thank you in advance,
>>>>>>>
>>>>>>> Brian
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> srslte-users mailing list
>>>>>>> srslte-users at lists.softwareradiosystems.com
>>>>>>> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
>>>>>>>
>>>>>>
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