[srslte-users] Measuring latency

[Steffen Heber]

Hi Andre and Kewin,

Thank you for your suggestions.

@Andre: Can you please give me any pointers for increasing the grant size
of enodeb?
@Kewin: As soon as I sync the time (i.e., get the time from internet), I
found the hour, minute, and second same across two machines. However, after
a certain time interval, there is a time drift (in millisecond range)
between two machines.


Thanks,
Steffen



On Wed, Oct 31, 2018 at 6:04 AM Kewin Rausch <krausch at fbk.eu> wrote:

> Hi Hopeless Heber, :-D
>
> did you check that the time stamps are fine? I mean, are the machine
> synced with times? Small differences can impact the computation.
> So maybe receiver and transmitter are doing their tasks, but since the
> timing does not have a common base (not synchronized), the final delta is
> wrong.
>
> Cheers,
> Kewin R.
>
> On Wed, Oct 31, 2018 at 10:56 AM Steffen Heber <hopeless.heber at gmail.com>
> wrote:
>
>>
>> I have added a couple of new fileds in one of RRC layer meassges and
>> wanted to measure the end-to-end transmission delay/latency of that message
>> because of additional fields. To achieve that I did the following: synced
>> the time of sender and the receiver machines to the local timezone; used
>> gettimeofday function to find the timestamps of message transmission (t1)
>> and reception (t2) at the sender and the receiver; the transmission
>> timestamp (t1) was included in the message so that the receiver can compute
>> the latency, i.e., delta=t2-t1. Unfortunately, I always found delta less
>> than 0 ms.
>>
>> Could anyone please give me any pointers to what I am doing wrong or a
>> better way to compute the latency of the message?
>>
>> Thanks,
>> Steffen
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>>
>
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