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Unipisa / Simu5G

Simu5G - 5G NR and LTE/LTE-A user-plane simulation model for OMNeT++ & INET
https://simu5g.org
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questions about retranssmission #133

Closed Jiacheng188 closed 1 year ago

Jiacheng188 commented 1 year ago

Hello, i am now working with uplink transmission situations and i am confused by the RAC process. According to the code in LteMacEnb::macHandleRac, all RACs are marked as successful. However in the RAC process if there are too many devices requesting for RAC, not all of them can get grant and the code in LteSchedulerEnbUl::racschedule shows that it will clear the racStatus after the RAC process of this TTI

racStatus.clear();

there may be devices are informed that they have succeed in the RAC process but wouldn't receive a grant. Is this a bug?

Jiacheng188 commented 1 year ago

Now i am not confused. When the Ue received a rac response indicating the rac process had been successful, only some timers were reset and bsr flag was turned on. The Ue still cannot send data until it received a grant in LteMacUeD2D::macHandleGrant where the grant was cached and the flag _racRequested_ was set to false. However, if the Ue didn't receive any grant when the network was too crowded, it would continuously check RAC, and until the raRespTimer and racRequested_ flag were invalid the Ue repeated to send RAC request.