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Bugifx simultaneous RACH with multiple UEs

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- replaced taus with a random seed + random number generation
- this fixes the bug with multiple UEs starting RA in the same time frame and slot
  and selecting the same preamble index
This commit is contained in:
Guido Casati
2021-10-07 15:56:43 +02:00
parent 314760acf3
commit 218de9342d
1 changed files with 14 additions and 10 deletions
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openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
+14 -10
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@@ -30,9 +30,6 @@
* \warning
*/
/* Tools */
#include "SIMULATION/TOOLS/sim.h" // for taus
/* RRC */
#include "NR_RACH-ConfigCommon.h"
#include "RRC/NR_UE/rrc_proto.h"
@@ -280,6 +277,10 @@ void ra_preambles_config(NR_PRACH_RESOURCES_t *prach_resources, NR_UE_MAC_INST_t
int PLThreshold = 0;
long deltaPreamble_Msg3 = 0;
uint8_t noGroupB = 0;
// Random seed generation
long long tmp = rdtsc_oai();
unsigned short int *seed = (unsigned short int*)&tmp;
RA_config_t *ra = &mac->ra;
NR_RACH_ConfigCommon_t *setup;
if (mac->scc) setup = mac->scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup;
@@ -378,28 +379,28 @@ void ra_preambles_config(NR_PRACH_RESOURCES_t *prach_resources, NR_UE_MAC_INST_t
if(ra->ra_PreambleIndex < 0 || ra->ra_PreambleIndex > 63) {
if (noGroupB) {
// use Group A preamble
ra->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % ra->cb_preambles_per_ssb);
ra->ra_PreambleIndex = ra->starting_preamble_nb + (nrand48(seed) % ra->cb_preambles_per_ssb);
ra->RA_usedGroupA = 1;
} else if ((ra->Msg3_size < messageSizeGroupA) && (dl_pathloss > PLThreshold)) {
// Group B is configured and RA preamble Group A is used
// - todo add condition on CCCH_sdu_size for initiation by CCCH
ra->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % sizeOfRA_PreamblesGroupA);
ra->ra_PreambleIndex = ra->starting_preamble_nb + (nrand48(seed) % sizeOfRA_PreamblesGroupA);
ra->RA_usedGroupA = 1;
} else {
// Group B preamble is configured and used
// the first sizeOfRA_PreamblesGroupA RA preambles belong to RA Preambles Group A
// the remaining belong to RA Preambles Group B
ra->ra_PreambleIndex = ra->starting_preamble_nb + sizeOfRA_PreamblesGroupA + ((taus()) % (ra->cb_preambles_per_ssb - sizeOfRA_PreamblesGroupA));
ra->ra_PreambleIndex = ra->starting_preamble_nb + sizeOfRA_PreamblesGroupA + (nrand48(seed) % (ra->cb_preambles_per_ssb - sizeOfRA_PreamblesGroupA));
ra->RA_usedGroupA = 0;
}
}
} else { // Msg3 is being retransmitted
if (ra->RA_usedGroupA && noGroupB) {
ra->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % ra->cb_preambles_per_ssb);
ra->ra_PreambleIndex = ra->starting_preamble_nb + (nrand48(seed) % ra->cb_preambles_per_ssb);
} else if (ra->RA_usedGroupA && !noGroupB){
ra->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % sizeOfRA_PreamblesGroupA);
ra->ra_PreambleIndex = ra->starting_preamble_nb + (nrand48(seed) % sizeOfRA_PreamblesGroupA);
} else {
ra->ra_PreambleIndex = ra->starting_preamble_nb + sizeOfRA_PreamblesGroupA + ((taus()) % (ra->cb_preambles_per_ssb - sizeOfRA_PreamblesGroupA));
ra->ra_PreambleIndex = ra->starting_preamble_nb + sizeOfRA_PreamblesGroupA + (nrand48(seed) % (ra->cb_preambles_per_ssb - sizeOfRA_PreamblesGroupA));
}
}
prach_resources->ra_PreambleIndex = ra->ra_PreambleIndex;
@@ -837,6 +838,9 @@ void nr_ra_failed(uint8_t mod_id, uint8_t CC_id, NR_PRACH_RESOURCES_t *prach_res
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
RA_config_t *ra = &mac->ra;
// Random seed generation
long long tmp = rdtsc_oai();
unsigned short int *seed = (unsigned short int*)&tmp;
ra->first_Msg3 = 1;
ra->ra_PreambleIndex = -1;
@@ -850,7 +854,7 @@ void nr_ra_failed(uint8_t mod_id, uint8_t CC_id, NR_PRACH_RESOURCES_t *prach_res
LOG_D(MAC, "In %s: [UE %d][%d.%d] Maximum number of RACH attempts (%d) reached, selecting backoff time...\n",
__FUNCTION__, mod_id, frame, slot, ra->preambleTransMax);
ra->RA_backoff_cnt = rand() % (prach_resources->RA_PREAMBLE_BACKOFF + 1);
ra->RA_backoff_cnt = nrand48(seed) % (prach_resources->RA_PREAMBLE_BACKOFF + 1);
prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER = 1;
prach_resources->RA_PREAMBLE_POWER_RAMPING_STEP += 2; // 2 dB increment
prach_resources->ra_PREAMBLE_RECEIVED_TARGET_POWER = nr_get_Po_NOMINAL_PUSCH(prach_resources, mod_id, CC_id);