the Msg3 UL grant requires the TTI in which the RAR has been received
to calcualte the correct timing. There was a race between PHY and Stack
thread.
This patch circumvents the issue by removing a PHY state member that only holds
the RAR Rx timing. In the new interface the RA proc passes the Rx TTI
to the PHY again when setting the UL grant so the PHY can calculate the
correct timing without any state.
this commit adds a complete DL HARQ entity to the MAC of the UE.
It also refactors demux into an own class and adapts the PHY-MAC
interface to use the new MAC capabilities.
* refactor some common methods to mac_common.cc
* add common mux_base class
* move UL PDU generation to mux class
* add logical channel registration to MAC, MUX, BSR
* add initial proc BSR
* add basic MAC NR test
* rework MAC interfaces