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inet-framework / simulte

SimuLTE - LTE System Level Simulation Model and Simulator for INET & OMNeT++ - deprecated, use Simu5G instead
https://simulte.omnetpp.org
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Simulte Bugs and inconsistency with the standards #28

Open yfen444 opened 6 years ago

yfen444 commented 6 years ago

Bugs:

  1. In LteSchedulerEnb.h, the use of unsigned int allocatedCws(MacNodeId nodeId) will create an entry for nodeId in the map-type variable allocatedCws_ if this entry doesn’t exist, but this function should only fetch the value, not create one. This bug doesn't really harm the simulation, because the incorrectly created entry has a mapped value of 0, which is actually true. But still, it's better the modify unsigned int allocatedCws(MacNodeId nodeId), or you will unintentionally create an entry for nodeId.

  2. In void LteMacEnbRealistic::handleSelfMessage() of LteMacEnbRealistic.cc, hit and het are firstly declared and used as harqRxBuffers_'s beginning and ending iterators to cycle through harqRxBuffers_. They are used later for the same purpose, but without reinitiating the value of hit. So the second cycle through harqRxBuffers_ is never executed.

  3. A SERIOUS BUG by tiny mistake. The observed problem is described in https://groups.google.com/forum/#!topic/omnetpp/_Xo0Yofoaao. The cause of the issue is: in unsigned int LteSchedulerEnb::scheduleGrant of LteSchedulerEnb.cc, RLC_HEADER_UM was not added to toServe in the first place, so toServe-MAC_HEADER-RLC_HEADER_UM<vQueueFrontSize is always true, thus the eNB always thought there were 2 bytes left within Ue.

This issue won't manifest if toServe-MAC_HEADER-RLC_HEADER_UM is smaller than 0 because the expression is unsigned int type. This is why you don't observe this problem when you run the original [Config VoIP-UL] in demo.

  1. eNB will schedule for a Ue, even though it knew that Ue reports a 0-sized BSR. I'm not sure if it's a bug or it's intended. But scheduling for 0-buffered Ue is clearly unnecessary.

  2. In unsigned int LteSchedulerEnb::scheduleGrant of LteSchedulerEnb.cc, I think an action of setting active to false for empty conn is needed under "if ((direction == UL || direction == D2D || direction_ == D2D_MULTI) && b == size-1)".

Inconsistency with the standards:

  1. The timing interval between a Grant and Data transmission is 2 ms, but it should be 4 ms, as specified by the standards.
FireChemist commented 5 years ago

Which file and line do you see the Grant and Data transmission as 2ms?