[srslte-users] New numerology in srslte

[Zhouyou Gu]

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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