[srslte-users] New numerology in srslte

[Justin Tallon]

Hey Zhouyou,

what rate are you using and what number of PRBs?
____
Justin Tallon Ph.D.

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

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


On Wed, Apr 1, 2020 at 2:07 PM Zhouyou Gu <guzhouyou at gmail.com> wrote:

> Hi Justin,
> Thanks for your prompt reply!
>
> It was not in performance mode and I have changed it to performance for
> srsUE and srsENB, as the following link
> https://askubuntu.com/questions/604720/setting-to-high-performance
>
> There are still some UUULLL messages.
> Is there any other tricks may help? :)
>
> Thanks again!
>
> Regards,
> Charles
>
>
>
> On Wed, 1 Apr 2020 at 22:50, Justin Tallon <
> justin.tallon at softwareradiosystems.com> wrote:
>
>> Hey Zhouyou,
>>
>> Are you sure your processor is running in PERFORMANCE mode?
>>
>> ____
>> Justin Tallon Ph.D.
>>
>> Software Radio Systems (SRS)
>> http://www.softwareradiosystems.com
>>
>> +353-86-067-0753 | justin.tallon at softwareradiosystems.com
>>
>>
>> On Wed, Apr 1, 2020 at 12:23 PM Zhouyou Gu <guzhouyou at gmail.com> wrote:
>>
>>> Thanks a lot ! Justin,
>>>
>>> Actually, I just made it working with subcarrier spacing at 30kHz,
>>> I made changes at the subcarrier spacing just like what you suggested.
>>>
>>> Two srsUEs can connect to the srsENB and I can ping them.
>>>
>>> Now the issue is that I found many UUULLL at srsUE
>>> I think it is because the TTI is shorter and the CPU is not faster
>>> enough to process the stack.
>>>
>>> I am wondering how can I improve this. What I am trying now is
>>>
>>>    - Try different CPU scheduling policy, e.g., SCHED_FIFO to  SCHED_RR
>>>    for DSP threads, Will this change help (I am not so familiar with CPU
>>>    scheduling)?
>>>    - Try allocate a fixed CPU mask for DSP.
>>>    - Or the only solution is to get a better CPU that can be
>>>    overclocked,
>>>
>>> My CPU is @3.4Ghz and Ubuntu has been configured with a low-latency
>>> kernel.
>>>
>>> Thanks a lot!
>>>
>>> Regards,
>>> Zhouyou Gu
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Wed, 1 Apr 2020 at 20:29, Justin Tallon <
>>> justin.tallon at softwareradiosystems.com> wrote:
>>>
>>>> Hey Zhouyou,
>>>>
>>>> If you want to play with the subcarrier spacing my advice would be to
>>>> pick a number of subcarriers you are happy with and then change the
>>>> sampling rate at which it runs.
>>>>
>>>> The easiest way this could be done is with a scaling parameter, scaling
>>>> the sampling rate by some factor. You will also need to change the timing
>>>> being sent to your RF frontend as this is passed in milliseconds, not
>>>> samples so this will also need to be scaled.
>>>>
>>>> In addition, pay attention to anywhere the subcarrier spacing (15000)
>>>> is used explicitly, especially in CFO calculations.
>>>>
>>>> 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, Mar 31, 2020 at 5:24 PM Zhouyou Gu <guzhouyou at gmail.com> wrote:
>>>>
>>>>> Dear srsLTE team,
>>>>>
>>>>> I am trying to implement a shorter TTI in srsLTE
>>>>> My platform is B210 and dell computer.
>>>>>
>>>>> To implement the shorter TTI, I have changed the subcarrier spacing to
>>>>> 30kHz (x2 than the original) and doubled the subcarrier spacing for PRACH
>>>>> as well.
>>>>> In addition, I have changed the clock rate setting.
>>>>>
>>>>> After I did this, srsUE cannot find the cell.
>>>>>
>>>>> What do you think about this idea?
>>>>> Is it possible on my platform (B210).
>>>>>
>>>>> If yes, what else may also need to be changed?
>>>>>
>>>>> Thanks a lot!
>>>>>
>>>>> Regards,
>>>>> Zhouyou
>>>>>
>>>>> _______________________________________________
>>>>> srslte-users mailing list
>>>>> srslte-users at lists.softwareradiosystems.com
>>>>> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
>>>>>
>>>>
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