- ta_timer at gNB side to control the transmission of TA to the UE. This is now happening every 20 slots.
- when the timer resets gNB is now transmitting the TA whether it is zero or not.
- introduced struct NR_UL_TIME_ALIGNMENT_t to handle configuration of time alignment related parameters.
- UE PHY RX: is now triggered through a flag when to store the TA command, the frame and slot
when the application should occur.
- UE PHY TX: when the tx frame and slot match the time alignment configuration, it process the TA command and applies the
TA update
- "nr_process_timing_advance": TA to be applied is commented out, need to be uncommented
- with introduced delay of 50 in rx_rf, TA update should be 34 in MAC CE
but this does not occur when ta is applied at UE side according to standard
- introduced ULSCH scheduler and NR RX SDU functions
- fixes to logic in UL fill RX indication
- added crc indication in UL RX
- temporary hardcoded UE_id to 0, rnti not considered in the logic
- Initial gNB DLSCH and UE spec scheduling implentation
- MAC PDU generation (including header as per TS 38.321)
- MAC PDU processing at UE side with extracion of TA updates
- General code cleanup
- Introduced NR MAC COMMON folder, moved common files here
In TDD mode, CQI requests are not possible in special subframes (at
least for some TDD configurations, see 36.213 7.2.3 that says "a
DL subframe is valid if it does not contain a DwPTS field if the
length is less than 7680 Ts").
In the code, we simply disable CQI requests in special subframes,
no matter what the length of DwPTS.
A problem can arise if the DCI0 for a given UE are sent only in
those special subframes. In this case the UE will never report
CQI and the eNB will use low MCS for this UE, impacting performances.
Another, related, problem is when there are several UEs. There again
one UE might always get its DCI0 in special subframes and thus never
report CQI. There again, performance issues.
This commit is an attempt to improve the situation.
It does two things.
1 - tag the UE as schedulable in the function UE_is_to_be_scheduled
if the cqi_req_timer is expired
2 - use cqi_req_timer as a criterium when ordering UEs for UL scheduling
The value chosen for the expiration of the cqi_req_timer in
UE_is_to_be_scheduled is quite high (300) because as the code is
today we may overschedule the UE for short bursts until we receive
a CQI from the UE. [TODO: fix the code properly to avoid this behavior.]
Note: the fairRR scheduler has not been analyzed and this commit may
not fix anything in case the fairRR scheduler is used.
Guido Casati