[srslte-users] srsUE USIM Support => Late Warnings

[David Rupprecht]

Hi Paul,

thanks for your answer.

Just for understanding: The NAS layer does *not* run in a separate yet?
The DSP threads in the PHY layer call directly the upper layer functions
without any decoupling and as the NAS layer takes so long the calling
DSP thread blocks the further process?

Just a short question to the message path. Considering the schematic
picture [1], the DL_INFO message comes from the MAX DEMUX over the RLC
layer to the NAS layer. However, looking at the code the RRC unit calls
nas->write_pdu(). So for me the RRC_DL_INFO message uses a path with the
RRC unit?

For handing off the message to a separate thread. I think I have two
options:
- Running the whole NAS unit in a separate thread using and define an
inter thread communication.
- Starting a new thread when receiving the an authentication request for
handling just this message.

Which option would you recommend?

Best regards,
David

[1]
http://www.softwareradiosystems.com/wp-content/uploads/2015/08/srsue_layer.png
 05.12.2016 10:33, Paul Sutton wrote:
> Hi David,
> 
> Have you tried handing off the message to a separate thread at the NAS
> layer?
> In the srsUE receive path, our high-priority DSP threads push messages
> all the way up through the stack. It looks like the hard USIM delay is
> blocking one of these threads for 43ms, resulting in RF timing misses.
> We have multiple DSP threads in a pool which can take up the slack at
> lower bandwidths but, as this is a 20MHz carrier, we can't afford to
> lose one for them for that long.
> 
> Best regards,
> Paul
> 
> 
> On 05/12/16 09:07, David Rupprecht wrote:
>> Dear all,
>>
>> I have implemented USIM Support for the srsUE using the PCSClib.
>> Unfortunately, the communication with the SIM Card takes to long (43 us
>> in the log) and the Authentication Response can not be sent correctly
>> indicated by RF late warnings with a crash.
>>
>> My question is, can I some how delay the Authentication Response? To my
>> understanding that should be specification conform, as the communication
>> on the NAS layer independent of the RF layer. Do you have any advises
>> concerning this problem?
>>
>> Best regards,
>> David
>>
>>
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> 
> -- 
> ________________________________________________________________
> Paul Sutton Ph.D.
> 
> Software Radio Systems (SRS)
> http://www.softwareradiosystems.com
> 
> +353-87-9813473 | paul at softwareradiosystems.com
> 
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-- 
M.Sc. David Rupprecht

Ruhr-University Bochum
Research Group Information Security
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