enb,nr: rewrite UL PDU processing to handle CEs in reverse order but SDUs in order

this makes sure that C-RNTI CE gets processed before any SDU gets processed.
but it also makes sure that all SDUs then are processed in-order to
avoid reordering at higher layers.
This commit is contained in:
Andre Puschmann 2021-10-27 17:05:30 +02:00 committed by Ismael Gomez
parent 6d0aafcf69
commit 5f837c0c67
2 changed files with 61 additions and 49 deletions

View File

@ -71,6 +71,7 @@ public:
private:
// helper methods
uint32_t buff_size_field_to_bytes(uint32_t buff_size_index, const srsran::bsr_format_nr_t& format);
int process_ce_subpdu(srsran::mac_sch_subpdu_nr& subpdu);
rlc_interface_mac* rlc = nullptr;
rrc_interface_mac_nr* rrc = nullptr;

View File

@ -74,59 +74,70 @@ int ue_nr::process_pdu(srsran::unique_byte_buffer_t pdu)
logger.info("Rx PDU: rnti=0x%x, %s", rnti, srsran::to_c_str(str_buffer));
}
// Reverse the order in which MAC subPDUs get processed.
// First, process MAC CEs, then MAC MAC subPDUs with MAC SDUs
// First, process MAC CEs in reverse order (CE like C-RNTI get handled first)
for (uint32_t n = mac_pdu_ul.get_num_subpdus(), i = mac_pdu_ul.get_num_subpdus() - 1; n > 0; --n, i = n - 1) {
srsran::mac_sch_subpdu_nr subpdu = mac_pdu_ul.get_subpdu(i);
logger.debug("Handling subPDU %d/%d: lcid=%d, sdu_len=%d",
i,
mac_pdu_ul.get_num_subpdus(),
subpdu.get_lcid(),
subpdu.get_sdu_length());
// Handle MAC CEs
switch (subpdu.get_lcid()) {
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::CRNTI: {
uint16_t c_rnti = subpdu.get_c_rnti();
if (true /*sched->ue_exists(c_crnti)*/) {
rrc->update_user(rnti, c_rnti);
rnti = c_rnti;
sched->ul_sr_info(rnti); // provide UL grant regardless of other BSR content for UE to complete RA
} else {
logger.warning("Updating user C-RNTI: rnti=0x%x already released.", c_rnti);
// Disable scheduling for all bearers. The new rnti will be removed on msg3 timer expiry in the RRC
for (uint32_t lcid = 0; lcid < sched_interface::MAX_LC; ++lcid) {
// sched->bearer_ue_rem(rnti, lcid);
}
}
} break;
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::SHORT_BSR:
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::SHORT_TRUNC_BSR: {
srsran::mac_sch_subpdu_nr::lcg_bsr_t sbsr = subpdu.get_sbsr();
uint32_t buffer_size_bytes = buff_size_field_to_bytes(sbsr.buffer_size, srsran::SHORT_BSR);
// Assume all LCGs are 0 if reported SBSR is 0
if (buffer_size_bytes == 0) {
for (uint32_t j = 0; j <= SCHED_NR_MAX_LC_GROUP; j++) {
sched->ul_bsr(rnti, j, 0);
}
} else {
sched->ul_bsr(rnti, sbsr.lcg_id, buffer_size_bytes);
}
} break;
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::LONG_BSR:
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::LONG_TRUNC_BSR: {
srsran::mac_sch_subpdu_nr::lbsr_t lbsr = subpdu.get_lbsr();
for (auto& lb : lbsr.list) {
sched->ul_bsr(rnti, lb.lcg_id, buff_size_field_to_bytes(lb.buffer_size, srsran::LONG_BSR));
}
} break;
default:
if (subpdu.is_sdu()) {
rrc->set_activity_user(rnti);
rlc->write_pdu(rnti, subpdu.get_lcid(), subpdu.get_sdu(), subpdu.get_sdu_length());
}
if (not subpdu.is_sdu()) {
if (process_ce_subpdu(subpdu) != SRSRAN_SUCCESS) {
return SRSRAN_ERROR;
}
}
}
// Second, handle all SDUs in order to avoid unnecessary reordering at higher layers
for (uint32_t i = 0; i < mac_pdu_ul.get_num_subpdus(); ++i) {
srsran::mac_sch_subpdu_nr subpdu = mac_pdu_ul.get_subpdu(i);
if (subpdu.is_sdu()) {
rrc->set_activity_user(rnti);
rlc->write_pdu(rnti, subpdu.get_lcid(), subpdu.get_sdu(), subpdu.get_sdu_length());
}
}
return SRSRAN_SUCCESS;
}
int ue_nr::process_ce_subpdu(srsran::mac_sch_subpdu_nr& subpdu)
{
// Handle MAC CEs
switch (subpdu.get_lcid()) {
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::CRNTI: {
uint16_t c_rnti = subpdu.get_c_rnti();
if (true /*sched->ue_exists(c_crnti)*/) {
rrc->update_user(rnti, c_rnti);
rnti = c_rnti;
sched->ul_sr_info(rnti); // provide UL grant regardless of other BSR content for UE to complete RA
} else {
logger.warning("Updating user C-RNTI: rnti=0x%x already released.", c_rnti);
// Disable scheduling for all bearers. The new rnti will be removed on msg3 timer expiry in the RRC
for (uint32_t lcid = 0; lcid < sched_interface::MAX_LC; ++lcid) {
// sched->bearer_ue_rem(rnti, lcid);
}
}
} break;
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::SHORT_BSR:
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::SHORT_TRUNC_BSR: {
srsran::mac_sch_subpdu_nr::lcg_bsr_t sbsr = subpdu.get_sbsr();
uint32_t buffer_size_bytes = buff_size_field_to_bytes(sbsr.buffer_size, srsran::SHORT_BSR);
// Assume all LCGs are 0 if reported SBSR is 0
if (buffer_size_bytes == 0) {
for (uint32_t j = 0; j <= SCHED_NR_MAX_LC_GROUP; j++) {
sched->ul_bsr(rnti, j, 0);
}
} else {
sched->ul_bsr(rnti, sbsr.lcg_id, buffer_size_bytes);
}
} break;
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::LONG_BSR:
case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::LONG_TRUNC_BSR: {
srsran::mac_sch_subpdu_nr::lbsr_t lbsr = subpdu.get_lbsr();
for (auto& lb : lbsr.list) {
sched->ul_bsr(rnti, lb.lcg_id, buff_size_field_to_bytes(lb.buffer_size, srsran::LONG_BSR));
}
} break;
default:
logger.warning("Unhandled subPDU with LCID=%d", subpdu.get_lcid());
}
return SRSRAN_SUCCESS;
}