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Reuse old TDA when allocating DL retransmissions

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- reusing old TDA whenever possible helps allocate DL retransmission when TDA chnges
- e.g. nrOfSymbols of new TDA > nrOfSymbols old TDA (leading to TBS size mismatching and allocation failure)
- This bugifx improves DL throughput stability in a multi-UE operation
This commit is contained in:
Guido
2023-02-06 11:46:27 +01:00
committed by Guido Casati
parent f984f49310
commit 389b9cf4ef
1 changed files with 14 additions and 4 deletions
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openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c
+14 -4
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@@ -408,16 +408,27 @@ bool allocate_dl_retransmission(module_id_t module_id,
const int tda = get_dl_tda(nr_mac, scc, slot);
AssertFatal(tda>=0,"Unable to find PDSCH time domain allocation in list\n");
if (tda == retInfo->time_domain_allocation &&
/* Check first whether the old TDA can be reused
* this helps allocate retransmission when TDA changes (e.g. new nrOfSymbols > old nrOfSymbols) */
NR_tda_info_t temp_tda = nr_get_pdsch_tda_info(dl_bwp, tda);
const uint16_t temp_bitmap = SL_to_bitmap(temp_tda.startSymbolIndex, temp_tda.nrOfSymbols);
NR_tda_info_t *old_tda = &retInfo->tda_info;
const uint16_t old_bitmap = SL_to_bitmap(old_tda->startSymbolIndex, old_tda->nrOfSymbols);
bool reuse_old_tda = (old_bitmap & temp_bitmap) == old_bitmap;
LOG_D(NR_MAC, "[UE %x] %s old TDA, %s number of layers\n",
UE->rnti,
reuse_old_tda ? "reuse" : "do not reuse",
layers == retInfo->nrOfLayers ? "same" : "different");
if ((reuse_old_tda || tda == retInfo->time_domain_allocation) &&
layers == retInfo->nrOfLayers) {
NR_tda_info_t *tda_info = &retInfo->tda_info;
/* Check that there are enough resources for retransmission */
while (rbSize < retInfo->rbSize) {
rbStart += rbSize; /* last iteration rbSize was not enough, skip it */
rbSize = 0;
const int slbitmap = SL_to_bitmap(tda_info->startSymbolIndex, tda_info->nrOfSymbols);
const uint16_t slbitmap = reuse_old_tda ? old_bitmap : temp_bitmap;
while (rbStart < bwpSize && (rballoc_mask[rbStart] & slbitmap) != slbitmap)
rbStart++;
@@ -434,7 +445,6 @@ bool allocate_dl_retransmission(module_id_t module_id,
} else {
/* the retransmission will use a different time domain allocation, check
* that we have enough resources */
NR_tda_info_t temp_tda = nr_get_pdsch_tda_info(dl_bwp, tda);
NR_pdsch_dmrs_t temp_dmrs = get_dl_dmrs_params(scc,
dl_bwp,
&temp_tda,