In xRAN, it appears that T1a/Ta4 values are assumed to be within a TTI.
When T1a/Ta4 values with larger than a TTI are used, this causes two issues: (1) C-plane packets to be generated later than expected and (2) oai_xran_fh_rx_callback() receives the wrong timing information resulting in potentially empty/stale PUSCH/PRACH data to be read.
In this patch, we modify xRAN to make it handle large T1a/Ta4 values properly.
The changes include: (1) three additional variables in offset_num_slots_* (xran_dev.h), (2) modify "xran_timing_create_cbs" and "xran_timer_arm_for_deadline" (xran_cb_proc.c), and (3) revise "tx_cp_dl_cb" and "tx_cp_ul_cb" (xran_main.c).
Additionally, we add additional guard conditions to prevent xran_tx_proc.c from sending U-plane packets when it is not a downlink slot.
Xin Zhe Khooi
003d72c859