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5a9014e9607f3249f4ead9ff6ef6049e21a978c8
openairinterface5g/openair2/LAYER2/NR_MAC_UE/nr_ra_procedures.c
T
cig 5a9014e960 Review of MR 1025 
- bugfix in nr_ue_dci_configuration
- cleanup of irrelevant RA-related data structure members in UE
- moved msg1 init condition to MAC
- minor fixes concerning init_ra function
2021-01-29 12:44:28 +01:00

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/*
* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The OpenAirInterface Software Alliance licenses this file to You under
* the OAI Public License, Version 1.1 (the "License"); you may not use this file
* except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.openairinterface.org/?page_id=698
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*-------------------------------------------------------------------------------
* For more information about the OpenAirInterface (OAI) Software Alliance:
* contact@openairinterface.org
*/
/*! \file ra_procedures.c
* \brief Routines for UE MAC-layer Random Access procedures (TS 38.321, Release 15)
* \author R. Knopp, Navid Nikaein, Guido Casati
* \date 2019
* \version 0.1
* \company Eurecom
* \email: knopp@eurecom.fr navid.nikaein@eurecom.fr, guido.casati@iis.fraunhofer.de
* \note
* \warning
*/
/* Tools */
#include "SIMULATION/TOOLS/sim.h" // for taus
/* RRC */
#include "NR_RACH-ConfigCommon.h"
/* PHY */
#include "PHY/NR_TRANSPORT/nr_transport_common_proto.h"
#include "PHY/defs_common.h"
#include "PHY/defs_nr_common.h"
#include "PHY/NR_UE_ESTIMATION/nr_estimation.h"
/* MAC */
#include "LAYER2/NR_MAC_COMMON/nr_mac_extern.h"
#include "NR_MAC_COMMON/nr_mac.h"
#include "LAYER2/NR_MAC_UE/mac_proto.h"
void nr_get_RA_window(NR_UE_MAC_INST_t *mac);
// Random Access procedure initialization as per 5.1.1 and initialization of variables specific
// to Random Access type as specified in clause 5.1.1a (3GPP TS 38.321 version 16.2.1 Release 16)
// todo:
// - check if carrier to use is explicitly signalled then do (1) RA CARRIER SELECTION (SUL, NUL) (2) set PCMAX (currently hardcoded to 0)
void init_RA(module_id_t mod_id,
NR_PRACH_RESOURCES_t *prach_resources,
NR_RACH_ConfigCommon_t *nr_rach_ConfigCommon,
NR_RACH_ConfigGeneric_t *rach_ConfigGeneric,
NR_RACH_ConfigDedicated_t *rach_ConfigDedicated) {
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
RA_config_t *ra = &mac->ra;
ra->RA_active = 1;
ra->RA_RAPID_found = 0;
ra->preambleTransMax = 0;
ra->first_Msg3 = 1;
ra->starting_preamble_nb = 0;
ra->RA_backoff_cnt = 0;
prach_resources->RA_PREAMBLE_BACKOFF = 0;
prach_resources->RA_PCMAX = nr_get_Pcmax(mod_id);
prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER = 1;
prach_resources->RA_PREAMBLE_POWER_RAMPING_COUNTER = 1;
prach_resources->POWER_OFFSET_2STEP_RA = 0;
prach_resources->RA_SCALING_FACTOR_BI = 1;
if (rach_ConfigDedicated) {
if (rach_ConfigDedicated->cfra){
LOG_I(MAC, "Initialization of 4-step contention-free random access procedure\n");
prach_resources->RA_TYPE = RA_4STEP;
ra->cfra = 1;
} else if (rach_ConfigDedicated->ext1){
if (rach_ConfigDedicated->ext1->cfra_TwoStep_r16){
LOG_I(MAC, "In %s: setting RA type to 2-step...\n", __FUNCTION__);
prach_resources->RA_TYPE = RA_2STEP;
ra->cfra = 1;
} else {
LOG_E(MAC, "In %s: config not handled\n", __FUNCTION__);
}
} else {
LOG_E(MAC, "In %s: config not handled\n", __FUNCTION__);
}
} else {
LOG_E(MAC, "In %s: config not handled\n", __FUNCTION__);
}
if (prach_resources->RA_TYPE == RA_2STEP){
LOG_E(MAC, "Missing implementation of initialization of 2-step RA specific variables...\n");
} else if (prach_resources->RA_TYPE == RA_4STEP){
LOG_D(MAC, "Initialization of 4-step RA specific variables...\n");
switch (rach_ConfigGeneric->powerRampingStep){ // in dB
case 0:
prach_resources->RA_PREAMBLE_POWER_RAMPING_STEP = 0;
break;
case 1:
prach_resources->RA_PREAMBLE_POWER_RAMPING_STEP = 2;
break;
case 2:
prach_resources->RA_PREAMBLE_POWER_RAMPING_STEP = 4;
break;
case 3:
prach_resources->RA_PREAMBLE_POWER_RAMPING_STEP = 6;
break;
}
switch (rach_ConfigGeneric->preambleTransMax) {
case 0:
ra->preambleTransMax = 3;
break;
case 1:
ra->preambleTransMax = 4;
break;
case 2:
ra->preambleTransMax = 5;
break;
case 3:
ra->preambleTransMax = 6;
break;
case 4:
ra->preambleTransMax = 7;
break;
case 5:
ra->preambleTransMax = 8;
break;
case 6:
ra->preambleTransMax = 10;
break;
case 7:
ra->preambleTransMax = 20;
break;
case 8:
ra->preambleTransMax = 50;
break;
case 9:
ra->preambleTransMax = 100;
break;
case 10:
ra->preambleTransMax = 200;
break;
}
if (nr_rach_ConfigCommon->ext1) {
if (nr_rach_ConfigCommon->ext1->ra_PrioritizationForAccessIdentity){
LOG_D(MAC, "In %s:%d: Missing implementation for Access Identity initialization procedures\n", __FUNCTION__, __LINE__);
}
}
}
return;
}
void ssb_rach_config(RA_config_t *ra, NR_PRACH_RESOURCES_t *prach_resources, NR_RACH_ConfigCommon_t *nr_rach_ConfigCommon, fapi_nr_ul_config_prach_pdu *prach_pdu){
// Determine the SSB to RACH mapping ratio
// =======================================
if (prach_resources->RA_TYPE == RA_4STEP){
NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR ssb_perRACH_config = nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->present;
boolean_t multiple_ssb_per_ro; // true if more than one or exactly one SSB per RACH occasion, false if more than one RO per SSB
uint8_t ssb_rach_ratio; // Nb of SSBs per RACH or RACHs per SSB
int total_preambles_per_ssb;
uint8_t ssb_nb_in_ro;
int numberOfRA_Preambles = 64;
switch (ssb_perRACH_config){
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_oneEighth:
multiple_ssb_per_ro = false;
ssb_rach_ratio = 8;
ra->cb_preambles_per_ssb = 4 * (nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.oneEighth + 1);
break;
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_oneFourth:
multiple_ssb_per_ro = false;
ssb_rach_ratio = 4;
ra->cb_preambles_per_ssb = 4 * (nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.oneFourth + 1);
break;
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_oneHalf:
multiple_ssb_per_ro = false;
ssb_rach_ratio = 2;
ra->cb_preambles_per_ssb = 4 * (nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.oneHalf + 1);
break;
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_one:
multiple_ssb_per_ro = true;
ssb_rach_ratio = 1;
ra->cb_preambles_per_ssb = 4 * (nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.one + 1);
break;
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_two:
multiple_ssb_per_ro = true;
ssb_rach_ratio = 2;
ra->cb_preambles_per_ssb = 4 * (nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.two + 1);
break;
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_four:
multiple_ssb_per_ro = true;
ssb_rach_ratio = 4;
ra->cb_preambles_per_ssb = nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.four;
break;
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_eight:
multiple_ssb_per_ro = true;
ssb_rach_ratio = 8;
ra->cb_preambles_per_ssb = nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.eight;
break;
case NR_RACH_ConfigCommon__ssb_perRACH_OccasionAndCB_PreamblesPerSSB_PR_sixteen:
multiple_ssb_per_ro = true;
ssb_rach_ratio = 16;
ra->cb_preambles_per_ssb = nr_rach_ConfigCommon->ssb_perRACH_OccasionAndCB_PreamblesPerSSB->choice.sixteen;
break;
default:
AssertFatal(1 == 0, "Unsupported ssb_perRACH_config %d\n", ssb_perRACH_config);
break;
}
if (nr_rach_ConfigCommon->totalNumberOfRA_Preambles)
numberOfRA_Preambles = *(nr_rach_ConfigCommon->totalNumberOfRA_Preambles);
// Compute the proper Preamble selection params according to the selected SSB and the ssb_perRACH_OccasionAndCB_PreamblesPerSSB configuration
if ((true == multiple_ssb_per_ro) &&
(ssb_rach_ratio > 1)) {
total_preambles_per_ssb = numberOfRA_Preambles / ssb_rach_ratio;
ssb_nb_in_ro = prach_pdu->ssb_nb_in_ro;
ra->starting_preamble_nb = total_preambles_per_ssb * ssb_nb_in_ro;
}
else {
total_preambles_per_ssb = numberOfRA_Preambles;
ra->starting_preamble_nb = 0;
}
} else {
LOG_E(MAC, "In %s:%d: missing implementation for 2-step RA...\n", __FUNCTION__, __LINE__);
}
}
// This routine implements RA premable configuration according to
// section 5.1 (Random Access procedure) of 3GPP TS 38.321 version 16.2.1 Release 16
void ra_preambles_config(NR_PRACH_RESOURCES_t *prach_resources, NR_UE_MAC_INST_t *mac, int16_t dl_pathloss){
int messageSizeGroupA = 0;
int sizeOfRA_PreamblesGroupA = 0;
int messagePowerOffsetGroupB = 0;
int PLThreshold;
long deltaPreamble_Msg3 = 0;
uint8_t noGroupB = 0;
RA_config_t *ra = &mac->ra;
NR_ServingCellConfigCommon_t *scc = mac->scc;
NR_RACH_ConfigCommon_t *nr_rach_ConfigCommon = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup;
NR_RACH_ConfigGeneric_t *rach_ConfigGeneric = &nr_rach_ConfigCommon->rach_ConfigGeneric;
if (prach_resources->RA_TYPE == RA_4STEP){
if (scc->uplinkConfigCommon->initialUplinkBWP->pusch_ConfigCommon->choice.setup->msg3_DeltaPreamble){
deltaPreamble_Msg3 = (*scc->uplinkConfigCommon->initialUplinkBWP->pusch_ConfigCommon->choice.setup->msg3_DeltaPreamble) * 2; // dB
LOG_D(MAC, "In %s: deltaPreamble_Msg3 set to %ld\n", __FUNCTION__, deltaPreamble_Msg3);
}
if (!nr_rach_ConfigCommon->groupBconfigured) {
noGroupB = 1;
LOG_D(MAC, "In %s:%d: preambles group B is not configured...\n", __FUNCTION__, __LINE__);
} else {
// RA preambles group B is configured
// - Random Access Preambles group B is configured for 4-step RA type
// - Defining the number of RA preambles in RA Preamble Group A for each SSB
LOG_D(MAC, "In %s:%d: preambles group B is configured...\n", __FUNCTION__, __LINE__);
sizeOfRA_PreamblesGroupA = nr_rach_ConfigCommon->groupBconfigured->numberOfRA_PreamblesGroupA;
switch (nr_rach_ConfigCommon->groupBconfigured->ra_Msg3SizeGroupA){
/* - Threshold to determine the groups of RA preambles */
case 0:
messageSizeGroupA = 56;
break;
case 1:
messageSizeGroupA = 144;
break;
case 2:
messageSizeGroupA = 208;
break;
case 3:
messageSizeGroupA = 256;
break;
case 4:
messageSizeGroupA = 282;
break;
case 5:
messageSizeGroupA = 480;
break;
case 6:
messageSizeGroupA = 640;
break;
case 7:
messageSizeGroupA = 800;
break;
case 8:
messageSizeGroupA = 1000;
break;
case 9:
messageSizeGroupA = 72;
break;
default:
AssertFatal(1 == 0, "Unknown ra_Msg3SizeGroupA %lu\n", nr_rach_ConfigCommon->groupBconfigured->ra_Msg3SizeGroupA);
/* todo cases 10 -15*/
}
/* Power offset for preamble selection in dB */
messagePowerOffsetGroupB = -9999;
switch (nr_rach_ConfigCommon->groupBconfigured->messagePowerOffsetGroupB){
case 0:
messagePowerOffsetGroupB = -9999;
break;
case 1:
messagePowerOffsetGroupB = 0;
break;
case 2:
messagePowerOffsetGroupB = 5;
break;
case 3:
messagePowerOffsetGroupB = 8;
break;
case 4:
messagePowerOffsetGroupB = 10;
break;
case 5:
messagePowerOffsetGroupB = 12;
break;
case 6:
messagePowerOffsetGroupB = 15;
break;
case 7:
messagePowerOffsetGroupB = 18;
break;
default:
AssertFatal(1 == 0,"Unknown messagePowerOffsetGroupB %lu\n", nr_rach_ConfigCommon->groupBconfigured->messagePowerOffsetGroupB);
}
PLThreshold = prach_resources->RA_PCMAX - rach_ConfigGeneric->preambleReceivedTargetPower - deltaPreamble_Msg3 - messagePowerOffsetGroupB;
}
} else {
// todo:
// - groupB-ConfiguredTwoStepRA
// - msgA-DeltaPreamble
LOG_E(MAC, "In %s:%d: missing implementation for 2-step RA...\n", __FUNCTION__, __LINE__);
}
/* Msg3 has not been transmitted yet */
if (ra->first_Msg3) {
if (noGroupB) {
// use Group A preamble
prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % 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
prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % 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
prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + sizeOfRA_PreamblesGroupA + ((taus()) % (ra->cb_preambles_per_ssb - sizeOfRA_PreamblesGroupA));
ra->RA_usedGroupA = 0;
}
} else { // Msg3 is being retransmitted
if (ra->RA_usedGroupA && noGroupB) {
prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % ra->cb_preambles_per_ssb);
} else if (ra->RA_usedGroupA && !noGroupB){
prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + ((taus()) % sizeOfRA_PreamblesGroupA);
} else {
prach_resources->ra_PreambleIndex = ra->starting_preamble_nb + sizeOfRA_PreamblesGroupA + ((taus()) % (ra->cb_preambles_per_ssb - sizeOfRA_PreamblesGroupA));
}
}
}
// RA-RNTI computation (associated to PRACH occasion in which the RA Preamble is transmitted)
// - this does not apply to contention-free RA Preamble for beam failure recovery request
// - getting star_symb, SFN_nbr from table 6.3.3.2-3 (TDD and FR1 scenario)
// - ul_carrier_id: UL carrier used for RA preamble transmission, hardcoded for NUL carrier
// - f_id: index of the PRACH occasion in the frequency domain
// - s_id is starting symbol of the PRACH occasion [0...14]
// - t_id is the first slot of the PRACH occasion in a system frame [0...80]
uint16_t set_ra_rnti(NR_UE_MAC_INST_t *mac, fapi_nr_ul_config_prach_pdu *prach_pdu){
RA_config_t *ra = &mac->ra;
uint8_t ul_carrier_id = 0; // NUL
uint8_t f_id = prach_pdu->num_ra;
uint8_t t_id = prach_pdu->prach_slot;
uint8_t s_id = prach_pdu->prach_start_symbol;
ra->ra_rnti = 1 + s_id + 14 * t_id + 1120 * f_id + 8960 * ul_carrier_id;
LOG_D(MAC, "Computed ra_RNTI is %x \n", ra->ra_rnti);
return ra->ra_rnti;
}
// This routine implements Section 5.1.2 (UE Random Access Resource Selection)
// and Section 5.1.3 (Random Access Preamble Transmission) from 3GPP TS 38.321
// - currently the PRACH preamble is set through RRC configuration for 4-step CFRA mode
// todo:
// - determine next available PRACH occasion
// -- if RA initiated for SI request and ra_AssociationPeriodIndex and si-RequestPeriod are configured
// -- else if SSB is selected above
// -- else if CSI-RS is selected above
// - switch initialisation cases
// -- RA initiated by beam failure recovery operation (subclause 5.17 TS 38.321)
// --- SSB selection, set prach_resources->ra_PreambleIndex
// -- RA initiated by PDCCH: ra_preamble_index provided by PDCCH && ra_PreambleIndex != 0b000000
// --- set PREAMBLE_INDEX to ra_preamble_index
// --- select the SSB signalled by PDCCH
// -- RA initiated for SI request:
// --- SSB selection, set prach_resources->ra_PreambleIndex
// - condition on notification of suspending power ramping counter from lower layer (5.1.3 TS 38.321)
// - check if SSB or CSI-RS have not changed since the selection in the last RA Preamble tranmission
// - Contention-based RA preamble selection:
// -- selection of SSB with SS-RSRP above rsrp-ThresholdSSB else select any SSB
void nr_get_prach_resources(module_id_t mod_id,
int CC_id,
uint8_t gNB_id,
NR_PRACH_RESOURCES_t *prach_resources,
fapi_nr_ul_config_prach_pdu *prach_pdu,
NR_RACH_ConfigDedicated_t * rach_ConfigDedicated){
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
RA_config_t *ra = &mac->ra;
NR_RACH_ConfigCommon_t *nr_rach_ConfigCommon = mac->scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup;
LOG_D(PHY, "In %s: getting PRACH resources frame (first_Msg3 %d)\n", __FUNCTION__, ra->first_Msg3);
if (rach_ConfigDedicated) {
if (rach_ConfigDedicated->cfra){
uint8_t cfra_ssb_resource_idx = 0;
prach_resources->ra_PreambleIndex = rach_ConfigDedicated->cfra->resources.choice.ssb->ssb_ResourceList.list.array[cfra_ssb_resource_idx]->ra_PreambleIndex;
LOG_D(MAC, "In %s: selected RA preamble index %d for contention-free random access procedure for SSB with Id %d\n", __FUNCTION__, prach_resources->ra_PreambleIndex, cfra_ssb_resource_idx);
}
} else {
int16_t dl_pathloss = get_nr_PL(mod_id, CC_id, gNB_id);
ssb_rach_config(ra, prach_resources, nr_rach_ConfigCommon, prach_pdu);
ra_preambles_config(prach_resources, mac, dl_pathloss);
LOG_D(MAC, "[RAPROC] - Selected RA preamble index %d for contention-based random access procedure... \n", prach_resources->ra_PreambleIndex);
}
if (prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER > 1)
prach_resources->RA_PREAMBLE_POWER_RAMPING_COUNTER++;
prach_resources->ra_PREAMBLE_RECEIVED_TARGET_POWER = nr_get_Po_NOMINAL_PUSCH(prach_resources, mod_id, CC_id);
prach_resources->ra_RNTI = set_ra_rnti(mac, prach_pdu);
}
// TbD: RA_attempt_number not used
void nr_Msg1_transmitted(module_id_t mod_id, uint8_t CC_id, frame_t frameP, uint8_t gNB_id){
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
RA_config_t *ra = &mac->ra;
ra->ra_state = WAIT_RAR;
ra->RA_attempt_number++;
}
void nr_Msg3_transmitted(module_id_t mod_id, uint8_t CC_id, frame_t frameP, uint8_t gNB_id){
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
NR_RACH_ConfigCommon_t *nr_rach_ConfigCommon = mac->scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup;
RA_config_t *ra = &mac->ra;
LOG_D(MAC,"In %s: [UE %d] Frame %d, CB-RA: starting contention resolution timer\n", __FUNCTION__, mod_id, frameP);
// start contention resolution timer
ra->RA_contention_resolution_cnt = (nr_rach_ConfigCommon->ra_ContentionResolutionTimer + 1) * 8;
ra->RA_contention_resolution_timer_active = 1;
}
/////////////////////////////////////////////////////////////////////////
// This function handles:
// - Random Access Preamble Initialization (5.1.1 TS 38.321)
// - Random Access Response reception (5.1.4 TS 38.321)
/// In the current implementation, RA is 4-step contention free only
/////////////////////////////////////////////////////////////////////////
// todo TS 38.321:
// - BWP operation (subclause 5.15 TS 38.321)
// - beam failure recovery
// - handle initialization by handover
// - handle DL assignment on PDCCH for RA-RNTI
// - transmission on DCCH using PRACH (during handover, or sending SR for example)
// - take into account MAC CEs in size_sdu (currently hardcoded size to 1 MAC subPDU and 1 padding subheader)
// - fix rrc data req logic
// - retrieve TBS
// - add mac_rrc_nr_data_req_ue, etc ...
// - Msg3 Retransmissions to be scheduled by DCI 0_0
uint8_t nr_ue_get_rach(NR_PRACH_RESOURCES_t *prach_resources,
fapi_nr_ul_config_prach_pdu *prach_pdu,
module_id_t mod_id,
int CC_id,
frame_t frame,
uint8_t gNB_id,
int nr_slot_tx){
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
RA_config_t *ra = &mac->ra;
uint8_t mac_sdus[MAX_NR_ULSCH_PAYLOAD_BYTES];
uint8_t lcid = UL_SCH_LCID_CCCH_MSG3, *payload;
uint16_t size_sdu = 0;
unsigned short post_padding;
NR_ServingCellConfigCommon_t *scc = mac->scc;
AssertFatal(scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup != NULL, "In %s: FATAL! nr_rach_ConfigCommon is NULL...\n", __FUNCTION__);
NR_RACH_ConfigCommon_t *setup = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup;
AssertFatal(&setup->rach_ConfigGeneric != NULL, "In %s: FATAL! rach_ConfigGeneric is NULL...\n", __FUNCTION__);
NR_RACH_ConfigGeneric_t *rach_ConfigGeneric = &setup->rach_ConfigGeneric;
NR_RACH_ConfigDedicated_t *rach_ConfigDedicated = ra->rach_ConfigDedicated;
uint8_t sdu_lcids[NB_RB_MAX] = {0};
uint16_t sdu_lengths[NB_RB_MAX] = {0};
int TBS_bytes = 848, header_length_total=0, num_sdus, offset, mac_ce_len;
// Delay init RA procedure to allow the convergence of the IIR filter on PRACH noise measurements at gNB side
if (!prach_resources->init_msg1) {
if (((MAX_FRAME_NUMBER + frame - prach_resources->sync_frame) % MAX_FRAME_NUMBER) > 150){
prach_resources->init_msg1 = 1;
} else {
return 0;
}
}
if (prach_resources->init_msg1) {
if (ra->RA_active == 0) {
/* RA not active - checking if RRC is ready to initiate the RA procedure */
LOG_D(MAC, "RA not active. Checking for data to transmit from upper layers...\n");
payload = (uint8_t*) &mac->CCCH_pdu.payload;
mac_ce_len = 0;
num_sdus = 1;
post_padding = 1;
if (0){
// initialisation by RRC
// CCCH PDU
// size_sdu = (uint16_t) mac_rrc_data_req_ue(mod_id,
// CC_id,
// frame,
// CCCH,
// 1,
// mac_sdus,
// gNB_id,
// 0);
LOG_D(MAC,"[UE %d] Frame %d: Requested RRCConnectionRequest, got %d bytes\n", mod_id, frame, size_sdu);
} else {
// fill ulsch_buffer with random data
for (int i = 0; i < TBS_bytes; i++){
mac_sdus[i] = (unsigned char) (lrand48()&0xff);
}
//Sending SDUs with size 1
//Initialize elements of sdu_lcids and sdu_lengths
sdu_lcids[0] = lcid;
sdu_lengths[0] = TBS_bytes - 3 - post_padding - mac_ce_len;
header_length_total += 2 + (sdu_lengths[0] >= 128);
size_sdu += sdu_lengths[0];
}
if (size_sdu > 0) {
LOG_D(MAC, "[UE %d][%d.%d]: starting initialisation Random Access Procedure...\n", mod_id, frame, nr_slot_tx);
ra->Msg3_size = size_sdu + sizeof(NR_MAC_SUBHEADER_SHORT) + sizeof(NR_MAC_SUBHEADER_SHORT);
init_RA(mod_id, prach_resources, setup, rach_ConfigGeneric, rach_ConfigDedicated);
prach_resources->Msg3 = payload;
nr_get_RA_window(mac);
// Fill in preamble and PRACH resources
if (ra->generate_nr_prach == 1)
nr_get_prach_resources(mod_id, CC_id, gNB_id, prach_resources, prach_pdu, rach_ConfigDedicated);
offset = nr_generate_ulsch_pdu((uint8_t *) mac_sdus, // sdus buffer
(uint8_t *) payload, // UL MAC pdu pointer
num_sdus, // num sdus
sdu_lengths, // sdu length
sdu_lcids, // sdu lcid
0, // power headroom
0, // crnti
0, // truncated bsr
0, // short bsr
0, // long_bsr
post_padding,
0);
// Padding: fill remainder with 0
if (post_padding > 0){
for (int j = 0; j < (TBS_bytes - offset); j++)
payload[offset + j] = 0; // mac_pdu[offset + j] = 0;
}
}
} else if (ra->RA_window_cnt != -1) { // RACH is active
LOG_D(MAC, "In %s [%d.%d] RA is active: RA window count %d, RA backoff count %d\n", __FUNCTION__, frame, nr_slot_tx, ra->RA_window_cnt, ra->RA_backoff_cnt);
if (ra->RA_BI_found){
prach_resources->RA_PREAMBLE_BACKOFF = prach_resources->RA_SCALING_FACTOR_BI * ra->RA_backoff_indicator;
} else {
prach_resources->RA_PREAMBLE_BACKOFF = 0;
}
if (ra->RA_window_cnt >= 0 && ra->RA_RAPID_found == 1) {
// Reset RA_active flag: it disables Msg3 retransmission (8.3 of TS 38.213)
nr_ra_succeeded(mod_id, frame, nr_slot_tx);
} else if (ra->RA_window_cnt == 0 && !ra->RA_RAPID_found) {
LOG_I(MAC, "[UE %d][%d:%d] RAR reception failed \n", mod_id, frame, nr_slot_tx);
nr_ra_failed(mod_id, CC_id, prach_resources, frame, nr_slot_tx);
} else if (ra->RA_window_cnt > 0) {
LOG_D(MAC, "[UE %d][%d.%d]: RAR not received yet (RA window count %d) \n", mod_id, frame, nr_slot_tx, ra->RA_window_cnt);
// Fill in preamble and PRACH resources
ra->RA_window_cnt--;
nr_get_prach_resources(mod_id, CC_id, gNB_id, prach_resources, prach_pdu, rach_ConfigDedicated);
} else if (ra->RA_backoff_cnt > 0) {
LOG_D(MAC, "[UE %d][%d.%d]: RAR not received yet (RA backoff count %d) \n", mod_id, frame, nr_slot_tx, ra->RA_backoff_cnt);
ra->RA_backoff_cnt--;
if ((ra->RA_backoff_cnt > 0 && ra->generate_nr_prach == 1) || ra->RA_backoff_cnt == 0){
nr_get_prach_resources(mod_id, CC_id, gNB_id, prach_resources, prach_pdu, rach_ConfigDedicated);
}
}
}
}
if (ra->RA_contention_resolution_timer_active){
nr_ue_contention_resolution(mod_id, CC_id, frame, nr_slot_tx, prach_resources);
}
return ra->generate_nr_prach;
}
void nr_get_RA_window(NR_UE_MAC_INST_t *mac){
uint8_t mu, ra_ResponseWindow;
RA_config_t *ra = &mac->ra;
NR_ServingCellConfigCommon_t *scc = mac->scc;
NR_RACH_ConfigCommon_t *setup = scc->uplinkConfigCommon->initialUplinkBWP->rach_ConfigCommon->choice.setup;
NR_RACH_ConfigGeneric_t *rach_ConfigGeneric = &setup->rach_ConfigGeneric;
NR_FrequencyInfoDL_t *frequencyInfoDL = scc->downlinkConfigCommon->frequencyInfoDL;
ra_ResponseWindow = rach_ConfigGeneric->ra_ResponseWindow;
if (setup->msg1_SubcarrierSpacing)
mu = *setup->msg1_SubcarrierSpacing;
else
mu = frequencyInfoDL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;
ra->RA_window_cnt = ra->RA_offset*nr_slots_per_frame[mu]; // taking into account the 2 frames gap introduced by OAI gNB
switch (ra_ResponseWindow) {
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl1:
ra->RA_window_cnt += 1;
break;
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl2:
ra->RA_window_cnt += 2;
break;
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl4:
ra->RA_window_cnt += 4;
break;
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl8:
ra->RA_window_cnt += 8;
break;
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl10:
ra->RA_window_cnt += 10;
break;
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl20:
ra->RA_window_cnt += 20;
break;
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl40:
ra->RA_window_cnt += 40;
break;
case NR_RACH_ConfigGeneric__ra_ResponseWindow_sl80:
ra->RA_window_cnt += 80;
break;
}
}
////////////////////////////////////////////////////////////////////////////
/////////* Random Access Contention Resolution (5.1.35 TS 38.321) */////////
////////////////////////////////////////////////////////////////////////////
// Handling contention resolution timer
// WIP todo:
// - beam failure recovery
// - RA completed
void nr_ue_contention_resolution(module_id_t module_id, int cc_id, frame_t frame, int slot, NR_PRACH_RESOURCES_t *prach_resources){
NR_UE_MAC_INST_t *mac = get_mac_inst(module_id);
RA_config_t *ra = &mac->ra;
if (ra->RA_contention_resolution_timer_active == 1) {
ra->RA_contention_resolution_cnt--;
LOG_D(MAC, "In %s: [%d.%d] RA contention resolution timer %d\n", __FUNCTION__, frame, slot, ra->RA_contention_resolution_cnt);
if (ra->RA_contention_resolution_cnt == 0) {
ra->t_crnti = 0;
ra->RA_active = 0;
ra->RA_contention_resolution_timer_active = 0;
// Signal PHY to quit RA procedure
LOG_E(MAC, "[UE %d] CB-RA: Contention resolution timer has expired, RA procedure has failed...\n", module_id);
nr_ra_failed(module_id, cc_id, prach_resources, frame, slot);
}
}
}
// Handlig successful RA completion @ MAC layer
// according to section 5 of 3GPP TS 38.321 version 16.2.1 Release 16
// todo:
// - complete handling of received contention-based RA preamble
void nr_ra_succeeded(module_id_t mod_id, frame_t frame, int slot){
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
RA_config_t *ra = &mac->ra;
if (ra->cfra) {
LOG_I(MAC, "[UE %d][%d.%d][RAPROC] RA procedure succeeded. CF-RA: RAR successfully received.\n", mod_id, frame, slot);
ra->RA_window_cnt = -1;
} else {
LOG_I(MAC, "[UE %d][%d.%d][RAPROC] RA procedure succeeded. CB-RA: Contention Resolution is successful.\n", mod_id, frame, slot);
ra->RA_contention_resolution_cnt = -1;
ra->RA_contention_resolution_timer_active = 0;
ra->t_crnti = 0;
LOG_D(MAC, "In %s: [UE %d][%d.%d] CB-RA: cleared contention resolution timer...\n", __FUNCTION__, mod_id, frame, slot);
}
LOG_D(MAC, "In %s: [UE %d] clearing RA_active flag...\n", __FUNCTION__, mod_id);
ra->RA_active = 0;
ra->generate_nr_prach = 2;
ra->ra_state = RA_SUCCEEDED;
}
// Handlig failure of RA procedure @ MAC layer
// according to section 5 of 3GPP TS 38.321 version 16.2.1 Release 16
// todo:
// - complete handling of received contention-based RA preamble
// - 2-step RA implementation
void nr_ra_failed(uint8_t mod_id, uint8_t CC_id, NR_PRACH_RESOURCES_t *prach_resources, frame_t frame, int slot) {
NR_UE_MAC_INST_t *mac = get_mac_inst(mod_id);
RA_config_t *ra = &mac->ra;
ra->first_Msg3 = 0;
ra->generate_nr_prach = 3;
ra->ra_state = RA_UE_IDLE;
prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER++;
if(prach_resources->RA_TYPE == RA_4STEP){
if (prach_resources->RA_PREAMBLE_TRANSMISSION_COUNTER == ra->preambleTransMax + 1){
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);
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);
} else {
// Resetting RA window
nr_get_RA_window(mac);
}
} else if (prach_resources->RA_TYPE == RA_2STEP){
LOG_E(MAC, "Missing implementation of RA failure handling for 2-step RA...\n");
}
}
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