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srsRAN/srsenb/src/stack/mac/scheduler_ue.cc

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/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#include <string.h>
#include "srsenb/hdr/stack/mac/scheduler.h"
#include "srsenb/hdr/stack/mac/scheduler_ue.h"
#include "srslte/common/log_helper.h"
#include "srslte/common/logmap.h"
#include "srslte/mac/pdu.h"
#include "srslte/srslte.h"
using srslte::tti_point;
namespace srsenb {
/******************************************************
* Helper Functions *
******************************************************/
namespace sched_utils {
//! Obtains TB size *in bytes* for a given MCS and N_{PRB}
uint32_t get_tbs_bytes(uint32_t mcs, uint32_t nof_alloc_prb, bool use_tbs_index_alt, bool is_ul)
{
int tbs_idx = srslte_ra_tbs_idx_from_mcs(mcs, use_tbs_index_alt, is_ul);
if (tbs_idx < SRSLTE_SUCCESS) {
tbs_idx = 0;
}
int tbs = srslte_ra_tbs_from_idx((uint32_t)tbs_idx, nof_alloc_prb);
if (tbs < SRSLTE_SUCCESS) {
tbs = 0;
}
return (uint32_t)tbs / 8U;
}
//! TS 36.321 sec 7.1.2 - MAC PDU subheader is 2 bytes if L<=128 and 3 otherwise
uint32_t get_mac_subheader_sdu_size(uint32_t sdu_bytes)
{
return sdu_bytes == 0 ? 0 : (sdu_bytes > 128 ? 3 : 2);
}
/**
* Count number of PRBs present in a DL RBG mask
* @param bitmask DL RBG mask
* @return number of prbs
*/
uint32_t count_prb_per_tb(const sched_cell_params_t& cell_params, const rbgmask_t& bitmask)
{
uint32_t nof_prb = 0;
for (uint32_t i = 0; i < bitmask.size(); i++) {
if (bitmask.test(i)) {
nof_prb += std::min(cell_params.cfg.cell.nof_prb - (i * cell_params.P), cell_params.P);
}
}
return nof_prb;
}
} // namespace sched_utils
bool operator==(const sched_interface::ue_cfg_t::cc_cfg_t& lhs, const sched_interface::ue_cfg_t::cc_cfg_t& rhs)
{
return lhs.enb_cc_idx == rhs.enb_cc_idx and lhs.active == rhs.active;
}
/*******************************************************
*
* Initialization and configuration functions
*
*******************************************************/
sched_ue::sched_ue() : log_h(srslte::logmap::get("MAC "))
{
reset();
}
void sched_ue::init(uint16_t rnti_, const std::vector<sched_cell_params_t>& cell_list_params_)
{
rnti = rnti_;
cell_params_list = &cell_list_params_;
Info("SCHED: Added user rnti=0x%x\n", rnti);
}
void sched_ue::set_cfg(const sched_interface::ue_cfg_t& cfg_)
{
// for the first configured cc, set it as primary cc
if (cfg.supported_cc_list.empty()) {
uint32_t primary_cc_idx = 0;
if (not cfg_.supported_cc_list.empty()) {
primary_cc_idx = cfg_.supported_cc_list[0].enb_cc_idx;
} else {
Warning("Primary cc idx not provided in scheduler ue_cfg. Defaulting to cc_idx=0\n");
}
// setup primary cc
main_cc_params = &(*cell_params_list)[primary_cc_idx];
cell = main_cc_params->cfg.cell;
max_msg3retx = main_cc_params->cfg.maxharq_msg3tx;
}
// update configuration
std::vector<sched::ue_cfg_t::cc_cfg_t> prev_supported_cc_list = std::move(cfg.supported_cc_list);
cfg = cfg_;
// update bearer cfgs
lch_handler.set_cfg(cfg_);
// in case carriers have been removed
while (carriers.size() > cfg.supported_cc_list.size()) {
// TODO: distinguish cell deactivation from reconfiguration
carriers.pop_back();
}
// in case carriers have been added or modified
bool scell_activation_state_changed = false;
for (uint32_t ue_idx = 0; ue_idx < cfg.supported_cc_list.size(); ++ue_idx) {
auto& cc_cfg = cfg.supported_cc_list[ue_idx];
if (ue_idx >= prev_supported_cc_list.size()) {
// New carrier needs to be added
carriers.emplace_back(cfg, (*cell_params_list)[cc_cfg.enb_cc_idx], rnti, ue_idx, current_tti);
} else if (cc_cfg.enb_cc_idx != prev_supported_cc_list[ue_idx].enb_cc_idx) {
// One carrier was added in the place of another
carriers[ue_idx] = cc_sched_ue{cfg, (*cell_params_list)[cc_cfg.enb_cc_idx], rnti, ue_idx, current_tti};
if (ue_idx == 0) {
log_h->info("SCHED: rnti=0x%x PCell is now enb_cc_idx=%d.\n", rnti, cc_cfg.enb_cc_idx);
}
} else {
// The SCell internal configuration may have changed
carriers[ue_idx].set_cfg(cfg);
}
scell_activation_state_changed |= ue_idx > 0 and (carriers[ue_idx].cc_state() == cc_st::activating or
carriers[ue_idx].cc_state() == cc_st::deactivating);
}
if (scell_activation_state_changed) {
pending_ces.emplace_back(srslte::dl_sch_lcid::SCELL_ACTIVATION);
log_h->info("SCHED: Enqueueing SCell Activation CMD for rnti=0x%x\n", rnti);
}
check_ue_cfg_correctness();
}
void sched_ue::reset()
{
cfg = {};
sr = false;
next_tpc_pusch = 1;
next_tpc_pucch = 1;
phy_config_dedicated_enabled = false;
cqi_request_tti = 0;
carriers.clear();
// erase all bearers
for (uint32_t i = 0; i < cfg.ue_bearers.size(); ++i) {
lch_handler.config_lcid(i, {});
}
}
void sched_ue::new_tti(srslte::tti_point new_tti)
{
current_tti = new_tti;
lch_handler.new_tti();
}
/// sanity check the UE CC configuration
void sched_ue::check_ue_cfg_correctness() const
{
using cc_t = sched::ue_cfg_t::cc_cfg_t;
const auto& cc_list = cfg.supported_cc_list;
bool has_scells = std::count_if(cc_list.begin(), cc_list.end(), [](const cc_t& c) { return c.active; }) > 1;
if (has_scells) {
// In case of CA, CQI configs must exist and cannot collide in the PUCCH
for (uint32_t i = 0; i < cc_list.size(); ++i) {
const auto& cc1 = cc_list[i];
if (not cc1.active) {
continue;
}
if (not cc1.dl_cfg.cqi_report.periodic_configured and not cc1.dl_cfg.cqi_report.aperiodic_configured) {
log_h->warning("SCHED: No CQI configuration was provided for UE scell index=%d \n", i);
} else if (cc1.dl_cfg.cqi_report.periodic_configured) {
for (uint32_t j = i + 1; j < cc_list.size(); ++j) {
if (cc_list[j].active and cc_list[j].dl_cfg.cqi_report.periodic_configured and
cc_list[j].dl_cfg.cqi_report.pmi_idx == cc1.dl_cfg.cqi_report.pmi_idx) {
log_h->warning(
"SCHED: The provided CQI configurations for UE scells %d and %d collide in the PUCCH\n", i, j);
}
}
}
}
}
}
/*******************************************************
*
* FAPI-like main scheduler interface.
*
*******************************************************/
void sched_ue::set_bearer_cfg(uint32_t lc_id, sched_interface::ue_bearer_cfg_t* cfg_)
{
cfg.ue_bearers[lc_id] = *cfg_;
lch_handler.config_lcid(lc_id, *cfg_);
}
void sched_ue::rem_bearer(uint32_t lc_id)
{
cfg.ue_bearers[lc_id] = sched_interface::ue_bearer_cfg_t{};
lch_handler.config_lcid(lc_id, sched_interface::ue_bearer_cfg_t{});
}
void sched_ue::phy_config_enabled(uint32_t tti, bool enabled)
{
for (cc_sched_ue& c : carriers) {
c.dl_cqi_tti = tti;
}
phy_config_dedicated_enabled = enabled;
}
void sched_ue::ul_buffer_state(uint8_t lcg_id, uint32_t bsr)
{
lch_handler.ul_bsr(lcg_id, bsr);
}
void sched_ue::ul_buffer_add(uint8_t lcid, uint32_t bytes)
{
lch_handler.ul_buffer_add(lcid, bytes);
}
void sched_ue::ul_phr(int phr)
{
power_headroom = phr;
}
void sched_ue::dl_buffer_state(uint8_t lc_id, uint32_t tx_queue, uint32_t retx_queue)
{
lch_handler.dl_buffer_state(lc_id, tx_queue, retx_queue);
}
void sched_ue::mac_buffer_state(uint32_t ce_code, uint32_t nof_cmds)
{
auto cmd = (ce_cmd)ce_code;
for (uint32_t i = 0; i < nof_cmds; ++i) {
if (cmd == ce_cmd::CON_RES_ID) {
pending_ces.push_front(cmd);
} else {
pending_ces.push_back(cmd);
}
}
Info("SCHED: %s for rnti=0x%x needs to be scheduled\n", to_string(cmd), rnti);
}
void sched_ue::set_sr()
{
sr = true;
}
void sched_ue::unset_sr()
{
sr = false;
}
bool sched_ue::pucch_sr_collision(uint32_t tti, uint32_t n_cce)
{
if (!phy_config_dedicated_enabled) {
return false;
}
if (cfg.pucch_cfg.sr_configured && srslte_ue_ul_sr_send_tti(&cfg.pucch_cfg, tti)) {
return (n_cce + cfg.pucch_cfg.N_pucch_1) == cfg.pucch_cfg.n_pucch_sr;
}
return false;
}
int sched_ue::set_ack_info(uint32_t tti_rx, uint32_t enb_cc_idx, uint32_t tb_idx, bool ack)
{
int tbs_acked = -1;
cc_sched_ue* c = find_ue_carrier(enb_cc_idx);
if (c != nullptr and c->cc_state() != cc_st::idle) {
std::pair<uint32_t, int> p2 = c->harq_ent.set_ack_info(tti_rx, tb_idx, ack);
tbs_acked = p2.second;
if (tbs_acked > 0) {
Debug("SCHED: Set DL ACK=%d for rnti=0x%x, pid=%d, tb=%d, tti=%d\n", ack, rnti, p2.first, tb_idx, tti_rx);
} else {
Warning("SCHED: Received ACK info for unknown TTI=%d\n", tti_rx);
}
} else {
log_h->warning("Received DL ACK for invalid cell index %d\n", enb_cc_idx);
}
return tbs_acked;
}
void sched_ue::set_ul_crc(srslte::tti_point tti_rx, uint32_t enb_cc_idx, bool crc_res)
{
cc_sched_ue* c = find_ue_carrier(enb_cc_idx);
if (c != nullptr and c->cc_state() != cc_st::idle) {
auto ret = c->harq_ent.set_ul_crc(tti_rx, 0, crc_res);
if (not ret.first) {
log_h->warning("Received UL CRC for invalid tti_rx=%d\n", (int)tti_rx.to_uint());
}
} else {
log_h->warning("Received UL CRC for invalid cell index %d\n", enb_cc_idx);
}
}
void sched_ue::set_dl_ri(uint32_t tti, uint32_t enb_cc_idx, uint32_t ri)
{
cc_sched_ue* c = find_ue_carrier(enb_cc_idx);
if (c != nullptr and c->cc_state() != cc_st::idle) {
c->dl_ri = ri;
c->dl_ri_tti = tti;
} else {
log_h->warning("Received DL RI for invalid cell index %d\n", enb_cc_idx);
}
}
void sched_ue::set_dl_pmi(uint32_t tti, uint32_t enb_cc_idx, uint32_t pmi)
{
cc_sched_ue* c = find_ue_carrier(enb_cc_idx);
if (c != nullptr and c->cc_state() != cc_st::idle) {
c->dl_pmi = pmi;
c->dl_pmi_tti = tti;
} else {
log_h->warning("Received DL PMI for invalid cell index %d\n", enb_cc_idx);
}
}
void sched_ue::set_dl_cqi(uint32_t tti, uint32_t enb_cc_idx, uint32_t cqi)
{
cc_sched_ue* c = find_ue_carrier(enb_cc_idx);
if (c != nullptr and c->cc_state() != cc_st::idle) {
c->set_dl_cqi(tti, cqi);
} else {
log_h->warning("Received DL CQI for invalid enb cell index %d\n", enb_cc_idx);
}
}
void sched_ue::set_ul_cqi(uint32_t tti, uint32_t enb_cc_idx, uint32_t cqi, uint32_t ul_ch_code)
{
cc_sched_ue* c = find_ue_carrier(enb_cc_idx);
if (c != nullptr and c->cc_state() != cc_st::idle) {
c->ul_cqi = cqi;
c->ul_cqi_tti = tti;
} else {
log_h->warning("Received SNR info for invalid cell index %d\n", enb_cc_idx);
}
}
void sched_ue::tpc_inc()
{
if (power_headroom > 0) {
next_tpc_pusch = 3;
next_tpc_pucch = 3;
}
log_h->info("SCHED: Set TCP=%d for rnti=0x%x\n", next_tpc_pucch, rnti);
}
void sched_ue::tpc_dec()
{
next_tpc_pusch = 0;
next_tpc_pucch = 0;
log_h->info("SCHED: Set TCP=%d for rnti=0x%x\n", next_tpc_pucch, rnti);
}
/*******************************************************
*
* Functions used to generate DCI grants
*
*******************************************************/
constexpr uint32_t min_mac_sdu_size = 5; // accounts for MAC SDU subheader and RLC header
/**
* Allocate space for multiple MAC SDUs (i.e. RLC PDUs) and corresponding MAC SDU subheaders
* @param data struct where the rlc pdu allocations are stored
* @param total_tbs available TB size for allocations for a single UE
* @param tbidx index of TB
* @return allocated bytes, which is always equal or lower than total_tbs
*/
uint32_t sched_ue::allocate_mac_sdus(sched_interface::dl_sched_data_t* data, uint32_t total_tbs, uint32_t tbidx)
{
// TS 36.321 sec 7.1.2 - MAC PDU subheader is 2 bytes if L<=128 and 3 otherwise
auto compute_subheader_size = [](uint32_t sdu_size) { return sdu_size > 128 ? 3 : 2; };
uint32_t rem_tbs = total_tbs;
// if we do not have enough bytes to fit MAC subheader and RLC header, skip MAC SDU allocation
while (rem_tbs >= min_mac_sdu_size) {
uint32_t max_sdu_bytes = rem_tbs - compute_subheader_size(rem_tbs - 2);
uint32_t alloc_sdu_bytes = lch_handler.alloc_rlc_pdu(&data->pdu[tbidx][data->nof_pdu_elems[tbidx]], max_sdu_bytes);
if (alloc_sdu_bytes == 0) {
break;
}
rem_tbs -= (alloc_sdu_bytes + compute_subheader_size(alloc_sdu_bytes)); // account for MAC sub-header
data->nof_pdu_elems[tbidx]++;
}
return total_tbs - rem_tbs;
}
/**
* Allocate space for pending MAC CEs
* @param data struct where the MAC CEs allocations are stored
* @param total_tbs available space in bytes for allocations
* @return number of bytes allocated
*/
uint32_t sched_ue::allocate_mac_ces(sched_interface::dl_sched_data_t* data, uint32_t total_tbs, uint32_t ue_cc_idx)
{
if (ue_cc_idx != 0) {
return 0;
}
int rem_tbs = total_tbs;
while (not pending_ces.empty()) {
int toalloc = srslte::ce_total_size(pending_ces.front());
if (rem_tbs < toalloc) {
break;
}
data->pdu[0][data->nof_pdu_elems[0]].lcid = (uint32_t)pending_ces.front();
data->nof_pdu_elems[0]++;
rem_tbs -= toalloc;
Info("SCHED: Added a MAC %s CE for rnti=0x%x\n", srslte::to_string(pending_ces.front()), rnti);
pending_ces.pop_front();
}
return total_tbs - rem_tbs;
}
/**
* Allocate space
* @param data
* @param total_tbs
* @param ue_cc_idx
* @return pair with allocated tbs and mcs
*/
std::pair<int, int> sched_ue::allocate_new_dl_mac_pdu(sched::dl_sched_data_t* data,
dl_harq_proc* h,
const rbgmask_t& user_mask,
uint32_t tti_tx_dl,
uint32_t ue_cc_idx,
uint32_t cfi,
uint32_t tb,
const char* dci_format)
{
srslte_dci_dl_t* dci = &data->dci;
uint32_t nof_prb = sched_utils::count_prb_per_tb(*carriers[ue_cc_idx].get_cell_cfg(), user_mask);
auto ret = compute_mcs_and_tbs(ue_cc_idx, tti_tx_dl, nof_prb, cfi, *dci);
int mcs = ret.first;
int tbs = ret.second;
/* Allocate MAC PDU (subheaders, CEs, and SDUS) */
int rem_tbs = tbs;
rem_tbs -= allocate_mac_ces(data, rem_tbs, ue_cc_idx);
rem_tbs -= allocate_mac_sdus(data, rem_tbs, tb);
/* Allocate DL UE Harq */
if (rem_tbs != tbs) {
h->new_tx(user_mask, tb, tti_tx_dl, mcs, tbs, data->dci.location.ncce);
Debug("SCHED: Alloc DCI format%s new mcs=%d, tbs=%d, nof_prb=%d\n", dci_format, mcs, tbs, nof_prb);
} else {
Warning("SCHED: Failed to allocate DL harq pid=%d\n", h->get_id());
}
return std::make_pair(tbs, mcs);
}
int sched_ue::generate_dl_dci_format(uint32_t pid,
sched_interface::dl_sched_data_t* data,
uint32_t tti_tx_dl,
uint32_t ue_cc_idx,
uint32_t cfi,
const rbgmask_t& user_mask)
{
srslte_dci_format_t dci_format = get_dci_format();
int tbs = 0;
switch (dci_format) {
case SRSLTE_DCI_FORMAT1:
tbs = generate_format1(pid, data, tti_tx_dl, ue_cc_idx, cfi, user_mask);
break;
case SRSLTE_DCI_FORMAT2:
tbs = generate_format2(pid, data, tti_tx_dl, ue_cc_idx, cfi, user_mask);
break;
case SRSLTE_DCI_FORMAT2A:
tbs = generate_format2a(pid, data, tti_tx_dl, ue_cc_idx, cfi, user_mask);
break;
default:
Error("DCI format (%d) not implemented\n", dci_format);
}
return tbs;
}
// Generates a Format1 dci
// > return 0 if allocation is invalid
int sched_ue::generate_format1(uint32_t pid,
sched_interface::dl_sched_data_t* data,
uint32_t tti_tx_dl,
uint32_t ue_cc_idx,
uint32_t cfi,
const rbgmask_t& user_mask)
{
dl_harq_proc* h = &carriers[ue_cc_idx].harq_ent.dl_harq_procs()[pid];
srslte_dci_dl_t* dci = &data->dci;
int mcs = 0;
int tbs = 0;
// If the size of Format1 and Format1A is ambiguous in the common SS, use Format1A since the UE assumes
// Common SS when spaces collide
if (cell.nof_prb == 15 && carriers.size() > 1) {
dci->alloc_type = SRSLTE_RA_ALLOC_TYPE2;
dci->type2_alloc.mode = srslte_ra_type2_t::SRSLTE_RA_TYPE2_LOC;
rbg_interval rbg_int = rbg_interval::rbgmask_to_rbgs(user_mask);
uint32_t P = srslte_ra_type0_P(15);
prb_interval prb_int = prb_interval::rbgs_to_prbs(rbg_int, P);
dci->type2_alloc.riv =
srslte_ra_type2_to_riv(SRSLTE_MIN(prb_int.length(), cell.nof_prb), prb_int.start(), cell.nof_prb);
dci->format = SRSLTE_DCI_FORMAT1A;
if (prb_int.length() != P * user_mask.count()) {
// This happens if Type0 was using distributed allocation
Warning("SCHED: Can't use distributed RA due to DCI size ambiguity\n");
}
} else {
dci->alloc_type = SRSLTE_RA_ALLOC_TYPE0;
dci->type0_alloc.rbg_bitmask = (uint32_t)user_mask.to_uint64();
dci->format = SRSLTE_DCI_FORMAT1;
}
if (h->is_empty(0)) {
auto ret = allocate_new_dl_mac_pdu(data, h, user_mask, tti_tx_dl, ue_cc_idx, cfi, 0, "1");
tbs = ret.first;
mcs = ret.second;
} else {
h->new_retx(user_mask, 0, tti_tx_dl, &mcs, &tbs, data->dci.location.ncce);
Debug("SCHED: Alloc format1 previous mcs=%d, tbs=%d\n", mcs, tbs);
}
if (tbs > 0) {
dci->rnti = rnti;
dci->pid = h->get_id();
dci->ue_cc_idx = ue_cc_idx;
dci->tb[0].mcs_idx = (uint32_t)mcs;
dci->tb[0].rv = sched_utils::get_rvidx(h->nof_retx(0));
dci->tb[0].ndi = h->get_ndi(0);
dci->tpc_pucch = (uint8_t)next_tpc_pucch;
next_tpc_pucch = 1;
data->tbs[0] = (uint32_t)tbs;
data->tbs[1] = 0;
}
return tbs;
}
/**
* Based on the amount of tx data, allocated PRBs, DCI params, etc. compute a valid MCS and resulting TBS
* @param ue_cc_idx user carrier index
* @param tti_tx_dl tti when the tx will occur
* @param nof_alloc_prbs number of PRBs that were allocated
* @param cfi Number of control symbols in Subframe
* @param dci contains the RBG mask, and alloc type
* @return pair with MCS and TBS (in bytes)
*/
std::pair<int, int> sched_ue::compute_mcs_and_tbs(uint32_t ue_cc_idx,
uint32_t tti_tx_dl,
uint32_t nof_alloc_prbs,
uint32_t cfi,
const srslte_dci_dl_t& dci)
{
int mcs = 0, tbs_bytes = 0;
srslte::interval<uint32_t> req_bytes = get_requested_dl_bytes(ue_cc_idx);
// Calculate exact number of RE for this PRB allocation
srslte_pdsch_grant_t grant = {};
srslte_dl_sf_cfg_t dl_sf = {};
dl_sf.cfi = cfi;
dl_sf.tti = tti_tx_dl;
srslte_ra_dl_grant_to_grant_prb_allocation(&dci, &grant, carriers[ue_cc_idx].get_cell_cfg()->nof_prb());
uint32_t nof_re = srslte_ra_dl_grant_nof_re(&carriers[ue_cc_idx].get_cell_cfg()->cfg.cell, &dl_sf, &grant);
// Compute MCS+TBS
// Use a higher MCS for the Msg4 to fit in the 6 PRB case
if (carriers[ue_cc_idx].fixed_mcs_dl < 0 or not carriers[ue_cc_idx].dl_cqi_rx) {
// Dynamic MCS
tbs_bytes = carriers[ue_cc_idx].alloc_tbs_dl(nof_alloc_prbs, nof_re, req_bytes.stop(), &mcs);
} else {
// Fixed MCS
mcs = carriers[ue_cc_idx].fixed_mcs_dl;
tbs_bytes = sched_utils::get_tbs_bytes(
(uint32_t)carriers[ue_cc_idx].fixed_mcs_dl, nof_alloc_prbs, cfg.use_tbs_index_alt, false);
}
// If the number of prbs is not sufficient to fit minimum required bytes, increase the mcs
// NOTE: this may happen during ConRes CE tx when DL-CQI is still not available
while (tbs_bytes > 0 and (uint32_t) tbs_bytes < req_bytes.start() and mcs < 28) {
mcs++;
tbs_bytes = sched_utils::get_tbs_bytes((uint32_t)mcs, nof_alloc_prbs, cfg.use_tbs_index_alt, false);
}
return {mcs, tbs_bytes};
}
// Generates a Format2a dci
int sched_ue::generate_format2a(uint32_t pid,
sched_interface::dl_sched_data_t* data,
uint32_t tti_tx_dl,
uint32_t ue_cc_idx,
uint32_t cfi,
const rbgmask_t& user_mask)
{
dl_harq_proc* h = &carriers[ue_cc_idx].harq_ent.dl_harq_procs()[pid];
bool tb_en[SRSLTE_MAX_TB] = {false};
srslte_dci_dl_t* dci = &data->dci;
dci->alloc_type = SRSLTE_RA_ALLOC_TYPE0;
dci->type0_alloc.rbg_bitmask = (uint32_t)user_mask.to_uint64();
bool no_retx = true;
if (carriers[ue_cc_idx].dl_ri == 0) {
if (h->is_empty(1)) {
/* One layer, tb1 buffer is empty, send tb0 only */
tb_en[0] = true;
} else {
/* One layer, tb1 buffer is not empty, send tb1 only */
tb_en[1] = true;
}
} else {
/* Two layers, retransmit what TBs that have not been Acknowledged */
for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
if (!h->is_empty(tb)) {
tb_en[tb] = true;
no_retx = false;
}
}
/* Two layers, no retransmissions... */
if (no_retx) {
tb_en[0] = true;
tb_en[1] = true;
}
}
for (uint32_t tb = 0; tb < SRSLTE_MAX_TB; tb++) {
uint32_t req_bytes = get_pending_dl_new_data_total();
int mcs = 0;
int tbs = 0;
if (!h->is_empty(tb)) {
h->new_retx(user_mask, tb, tti_tx_dl, &mcs, &tbs, data->dci.location.ncce);
Debug("SCHED: Alloc format2/2a previous mcs=%d, tbs=%d\n", mcs, tbs);
} else if (tb_en[tb] && req_bytes > 0 && no_retx) {
auto ret = allocate_new_dl_mac_pdu(data, h, user_mask, tti_tx_dl, ue_cc_idx, cfi, tb, "2/2a");
tbs = ret.first;
mcs = ret.second;
}
/* Fill DCI TB dedicated fields */
if (tbs > 0 && tb_en[tb]) {
dci->tb[tb].mcs_idx = (uint32_t)mcs;
dci->tb[tb].rv = sched_utils::get_rvidx(h->nof_retx(tb));
if (!SRSLTE_DCI_IS_TB_EN(dci->tb[tb])) {
dci->tb[tb].rv = 2;
}
dci->tb[tb].ndi = h->get_ndi(tb);
dci->tb[tb].cw_idx = tb;
data->tbs[tb] = (uint32_t)tbs;
} else {
SRSLTE_DCI_TB_DISABLE(dci->tb[tb]);
data->tbs[tb] = 0;
}
}
/* Fill common fields */
dci->format = SRSLTE_DCI_FORMAT2A;
dci->rnti = rnti;
dci->ue_cc_idx = ue_cc_idx;
dci->pid = h->get_id();
dci->tpc_pucch = (uint8_t)next_tpc_pucch;
next_tpc_pucch = 1;
int ret = data->tbs[0] + data->tbs[1];
return ret;
}
// Generates a Format2 dci
int sched_ue::generate_format2(uint32_t pid,
sched_interface::dl_sched_data_t* data,
uint32_t tti,
uint32_t cc_idx,
uint32_t cfi,
const rbgmask_t& user_mask)
{
/* Call Format 2a (common) */
int ret = generate_format2a(pid, data, tti, cc_idx, cfi, user_mask);
/* Compute precoding information */
data->dci.format = SRSLTE_DCI_FORMAT2;
if ((SRSLTE_DCI_IS_TB_EN(data->dci.tb[0]) + SRSLTE_DCI_IS_TB_EN(data->dci.tb[1])) == 1) {
data->dci.pinfo = (uint8_t)(carriers[cc_idx].dl_pmi + 1) % (uint8_t)5;
} else {
data->dci.pinfo = (uint8_t)(carriers[cc_idx].dl_pmi & 1u);
}
return ret;
}
int sched_ue::generate_format0(sched_interface::ul_sched_data_t* data,
uint32_t tti,
uint32_t ue_cc_idx,
prb_interval alloc,
bool needs_pdcch,
srslte_dci_location_t dci_pos,
int explicit_mcs,
uci_pusch_t uci_type)
{
ul_harq_proc* h = get_ul_harq(tti, ue_cc_idx);
srslte_dci_ul_t* dci = &data->dci;
bool cqi_request = needs_cqi_unlocked(tti, true);
// Set DCI position
data->needs_pdcch = needs_pdcch;
dci->location = dci_pos;
int mcs = (explicit_mcs >= 0) ? explicit_mcs : carriers[ue_cc_idx].fixed_mcs_ul;
int tbs = 0;
bool is_newtx = h->is_empty(0);
if (is_newtx) {
uint32_t nof_retx;
// If Msg3 set different nof retx
nof_retx = (data->needs_pdcch) ? get_max_retx() : max_msg3retx;
if (mcs >= 0) {
tbs = srslte_ra_tbs_from_idx(srslte_ra_tbs_idx_from_mcs(mcs, false, true), alloc.length()) / 8;
} else {
// dynamic mcs
uint32_t req_bytes = get_pending_ul_new_data(tti, ue_cc_idx);
uint32_t N_srs = 0;
uint32_t nof_symb = 2 * (SRSLTE_CP_NSYMB(cell.cp) - 1) - N_srs;
uint32_t nof_re = nof_symb * alloc.length() * SRSLTE_NRE;
tbs = carriers[ue_cc_idx].alloc_tbs_ul(alloc.length(), nof_re, req_bytes, &mcs);
// Reduce MCS to fit UCI if transmitted in this grant
if (uci_type != UCI_PUSCH_NONE) {
// Calculate an approximation of the number of RE used by UCI
uint32_t nof_uci_re = 0;
// Add the RE for ACK
if (uci_type == UCI_PUSCH_ACK || uci_type == UCI_PUSCH_ACK_CQI) {
float beta = srslte_sch_beta_ack(cfg.uci_offset.I_offset_ack);
nof_uci_re += srslte_qprime_ack_ext(alloc.length(), nof_symb, 8 * tbs, carriers.size(), beta);
}
// Add the RE for CQI report (RI reports are transmitted on CQI slots. We do a conservative estimate here)
if (uci_type == UCI_PUSCH_CQI || uci_type == UCI_PUSCH_ACK_CQI || cqi_request) {
float beta = srslte_sch_beta_cqi(cfg.uci_offset.I_offset_cqi);
nof_uci_re += srslte_qprime_cqi_ext(alloc.length(), nof_symb, 8 * tbs, beta);
}
// Recompute again the MCS and TBS with the new spectral efficiency (based on the available RE for data)
if (nof_re >= nof_uci_re) {
tbs = carriers[ue_cc_idx].alloc_tbs_ul(alloc.length(), nof_re - nof_uci_re, req_bytes, &mcs);
}
// NOTE: if (nof_re < nof_uci_re) we should set TBS=0
}
}
h->new_tx(tti, mcs, tbs, alloc, nof_retx);
// Un-trigger the SR if data is allocated
if (tbs > 0) {
unset_sr();
}
} else {
// retx
h->new_retx(0, tti, &mcs, nullptr, alloc);
tbs = srslte_ra_tbs_from_idx(srslte_ra_tbs_idx_from_mcs(mcs, false, true), alloc.length()) / 8;
}
if (tbs >= 0) {
data->tbs = tbs;
dci->rnti = rnti;
dci->format = SRSLTE_DCI_FORMAT0;
dci->ue_cc_idx = ue_cc_idx;
dci->tb.ndi = h->get_ndi(0);
dci->cqi_request = cqi_request;
dci->freq_hop_fl = srslte_dci_ul_t::SRSLTE_RA_PUSCH_HOP_DISABLED;
dci->tpc_pusch = next_tpc_pusch;
next_tpc_pusch = 1;
dci->type2_alloc.riv = srslte_ra_type2_to_riv(alloc.length(), alloc.start(), cell.nof_prb);
// If there are no RE available for ULSCH but there is UCI to transmit, allocate PUSCH becuase
// resources have been reserved already and in CA it will be used to ACK other carriers
if (tbs == 0 && (cqi_request || uci_type != UCI_PUSCH_NONE)) {
// 8.6.1 and 8.6.2 36.213 second paragraph
dci->cqi_request = true;
dci->tb.mcs_idx = 29;
dci->tb.rv = 0; // No data is being transmitted
// Empty TBS PUSCH only accepts a maximum of 4 PRB. Resize the grant. This doesn't affect the MCS selection
// because there is no TB in this grant
if (alloc.length() > 4) {
alloc.set(alloc.start(), alloc.start() + 4);
}
} else if (tbs > 0) {
dci->tb.rv = sched_utils::get_rvidx(h->nof_retx(0));
if (!is_newtx && h->is_adaptive_retx()) {
dci->tb.mcs_idx = 28 + dci->tb.rv;
} else {
dci->tb.mcs_idx = mcs;
}
} else if (tbs == 0) {
log_h->warning("SCHED: No space for ULSCH while allocating format0. Discarding grant.\n");
} else {
log_h->error("SCHED: Unkown error while allocating format0\n");
}
}
return tbs;
}
/*******************************************************
*
* Functions used by scheduler or scheduler metric objects
*
*******************************************************/
uint32_t sched_ue::get_max_retx()
{
return cfg.maxharq_tx;
}
bool sched_ue::needs_cqi(uint32_t tti, uint32_t cc_idx, bool will_be_sent)
{
return needs_cqi_unlocked(tti, cc_idx, will_be_sent);
}
// Private lock-free implemenentation
bool sched_ue::needs_cqi_unlocked(uint32_t tti, uint32_t cc_idx, bool will_be_sent)
{
bool ret = false;
if (phy_config_dedicated_enabled && cfg.supported_cc_list[0].aperiodic_cqi_period && get_pending_dl_new_data() > 0) {
uint32_t interval = srslte_tti_interval(tti, carriers[cc_idx].dl_cqi_tti);
bool needscqi = interval >= cfg.supported_cc_list[0].aperiodic_cqi_period;
if (needscqi) {
uint32_t interval_sent = srslte_tti_interval(tti, cqi_request_tti);
if (interval_sent >= 16) {
if (will_be_sent) {
cqi_request_tti = tti;
}
Debug("SCHED: Needs_cqi, last_sent=%d, will_be_sent=%d\n", cqi_request_tti, will_be_sent);
ret = true;
}
}
}
return ret;
}
/// Use this function in the dl-metric to get the bytes to be scheduled. It accounts for the UE data,
/// the RAR resources, and headers
/// \return number of bytes to be allocated
uint32_t sched_ue::get_pending_dl_new_data_total()
{
uint32_t req_bytes = get_pending_dl_new_data();
if (req_bytes > 0) {
req_bytes += (req_bytes < 128) ? 2 : 3; // consider the header
}
return req_bytes;
}
/**
* Compute the range of RBGs that avoids segmentation of TM and MAC subheader data. Always computed for highest CFI
* @param ue_cc_idx carrier of the UE
* @return range of number of RBGs that a UE can allocate in a given subframe
*/
rbg_interval sched_ue::get_required_dl_rbgs(uint32_t ue_cc_idx)
{
srslte::interval<uint32_t> req_bytes = get_requested_dl_bytes(ue_cc_idx);
if (req_bytes == srslte::interval<uint32_t>{0, 0}) {
return {0, 0};
}
const auto* cellparams = carriers[ue_cc_idx].get_cell_cfg();
int pending_prbs =
carriers[ue_cc_idx].get_required_prb_dl(req_bytes.start(), cellparams->sched_cfg->max_nof_ctrl_symbols);
if (pending_prbs < 0) {
// Cannot fit allocation in given PRBs
log_h->error("SCHED: DL CQI=%d does now allow fitting %d non-segmentable DL tx bytes into the cell bandwidth. "
"Consider increasing initial CQI value.\n",
carriers[ue_cc_idx].dl_cqi,
req_bytes.start());
return {cellparams->nof_prb(), cellparams->nof_prb()};
}
uint32_t min_pending_rbg = cellparams->prb_to_rbg(pending_prbs);
pending_prbs = carriers[ue_cc_idx].get_required_prb_dl(req_bytes.stop(), cellparams->sched_cfg->max_nof_ctrl_symbols);
pending_prbs = (pending_prbs < 0) ? cellparams->nof_prb() : pending_prbs;
uint32_t max_pending_rbg = cellparams->prb_to_rbg(pending_prbs);
return {min_pending_rbg, max_pending_rbg};
}
/**
* Returns the range (min,max) of possible MAC PDU sizes.
* - the lower boundary value is set based on the following conditions:
* - if there is data in SRB0, the min value is the sum of:
* - SRB0 RLC data (Msg4) including MAC subheader and payload (no segmentation)
* - ConRes CE + MAC subheader (7 bytes)
* - elif there is data in other RBs, the min value is either:
* - first pending CE (subheader+CE payload) in queue, if it exists and we are in PCell. Or,
* - one subheader (2B) + one RLC header (<=3B) to allow one MAC PDU alloc
* - the upper boundary is set as a sum of:
* - total data in all SRBs and DRBs including the MAC subheaders
* - All CEs (ConRes and others) including respective MAC subheaders
* @ue_cc_idx carrier where allocation is being made
* @return
*/
srslte::interval<uint32_t> sched_ue::get_requested_dl_bytes(uint32_t ue_cc_idx)
{
const uint32_t min_alloc_bytes = 5; // 2 for subheader, and 3 for RLC header
// Convenience function to compute the number of bytes allocated for a given SDU
auto compute_sdu_total_bytes = [&min_alloc_bytes](uint32_t lcid, uint32_t buffer_bytes) {
if (buffer_bytes == 0) {
return 0u;
}
uint32_t subheader_and_sdu = buffer_bytes + sched_utils::get_mac_subheader_sdu_size(buffer_bytes);
return (lcid == 0) ? subheader_and_sdu : std::max(subheader_and_sdu, min_alloc_bytes);
};
/* Set Maximum boundary */
// Ensure there is space for ConRes and RRC Setup
// SRB0 is a special case due to being RLC TM (no segmentation possible)
if (not lch_handler.is_bearer_dl(0)) {
log_h->error("SRB0 must always be activated for DL\n");
return {};
}
if (carriers[ue_cc_idx].cc_state() != cc_st::active) {
return {};
}
uint32_t max_data = 0, min_data = 0;
uint32_t srb0_data = 0, rb_data = 0, sum_ce_data = 0;
bool is_dci_format1 = get_dci_format() == SRSLTE_DCI_FORMAT1;
if (is_dci_format1) {
srb0_data += compute_sdu_total_bytes(0, lch_handler.get_dl_retx(0));
srb0_data += compute_sdu_total_bytes(0, lch_handler.get_dl_tx(0));
}
// Add pending CEs
if (ue_cc_idx == 0) {
if (srb0_data == 0 and not pending_ces.empty() and pending_ces.front() == srslte::dl_sch_lcid::CON_RES_ID) {
// Wait for SRB0 data to be available for Msg4 before scheduling the ConRes CE
return {};
}
for (const ce_cmd& ce : pending_ces) {
sum_ce_data += srslte::ce_total_size(ce);
}
}
// Add pending data in remaining RLC buffers
for (int i = 1; i < sched_interface::MAX_LC; i++) {
if (lch_handler.is_bearer_dl(i)) {
rb_data += compute_sdu_total_bytes(i, lch_handler.get_dl_retx(i));
rb_data += compute_sdu_total_bytes(i, lch_handler.get_dl_tx(i));
}
}
max_data = srb0_data + sum_ce_data + rb_data;
/* Set Minimum boundary */
min_data = srb0_data;
if (not pending_ces.empty() and pending_ces.front() == ce_cmd::CON_RES_ID) {
min_data += srslte::ce_total_size(pending_ces.front());
}
if (min_data == 0) {
if (sum_ce_data > 0) {
min_data = srslte::ce_total_size(pending_ces.front());
} else if (rb_data > 0) {
min_data = min_alloc_bytes;
}
}
return {min_data, max_data};
}
/**
* Get pending DL data in RLC buffers + CEs
* @return
*/
uint32_t sched_ue::get_pending_dl_new_data()
{
if (std::none_of(
carriers.begin(), carriers.end(), [](const cc_sched_ue& cc) { return cc.cc_state() == cc_st::active; })) {
return 0;
}
uint32_t pending_data = 0;
for (int i = 0; i < sched_interface::MAX_LC; i++) {
if (lch_handler.is_bearer_dl(i)) {
pending_data += lch_handler.get_dl_tx(i) + lch_handler.get_dl_retx(i);
}
}
for (auto& ce : pending_ces) {
pending_data += srslte::ce_total_size(ce);
}
return pending_data;
}
uint32_t sched_ue::get_pending_ul_old_data(uint32_t cc_idx)
{
return get_pending_ul_old_data_unlocked(cc_idx);
}
uint32_t sched_ue::get_pending_ul_new_data(uint32_t tti, int this_ue_cc_idx)
{
static constexpr uint32_t lbsr_size = 4, sbsr_size = 2;
// Note: If there are no active bearers, scheduling requests are also ignored.
uint32_t pending_data = 0;
uint32_t active_lcgs = 0, pending_lcgs = 0;
for (int i = 0; i < sched_interface::MAX_LC_GROUP; i++) {
if (lch_handler.is_bearer_ul(i)) {
int bsr = lch_handler.get_bsr(i);
pending_data += bsr;
active_lcgs++;
pending_lcgs += (bsr > 0) ? 1 : 0;
}
}
if (pending_data > 0) {
// The scheduler needs to account for the possibility of BSRs being allocated in the UL grant.
// Otherwise, the UL grants allocated for very small RRC messages (e.g. rrcReconfigurationComplete)
// may be fully occupied by a BSR, and RRC the message transmission needs to be postponed.
pending_data += (pending_lcgs <= 1) ? sbsr_size : lbsr_size;
} else {
if (is_sr_triggered() and active_lcgs > 0 and this_ue_cc_idx >= 0) {
// Check if this_cc_idx is the carrier with highest CQI
uint32_t max_cqi = 0, max_cc_idx = 0;
for (uint32_t cc_idx = 0; cc_idx < carriers.size(); ++cc_idx) {
uint32_t sum_cqi = carriers[cc_idx].dl_cqi + carriers[cc_idx].ul_cqi;
if (carriers[cc_idx].cc_state() == cc_st::active and sum_cqi > max_cqi) {
max_cqi = sum_cqi;
max_cc_idx = cc_idx;
}
}
if ((int)max_cc_idx == this_ue_cc_idx) {
return 512;
}
}
for (uint32_t cc_idx = 0; cc_idx < carriers.size(); ++cc_idx) {
if (needs_cqi_unlocked(tti, cc_idx)) {
return 128;
}
}
}
// Subtract all the UL data already allocated in the UL harqs
uint32_t pending_ul_data = 0;
for (uint32_t cc_idx = 0; cc_idx < carriers.size(); ++cc_idx) {
pending_ul_data += get_pending_ul_old_data_unlocked(cc_idx);
}
pending_data = (pending_data > pending_ul_data) ? pending_data - pending_ul_data : 0;
if (pending_data > 0) {
Debug("SCHED: pending_data=%d, pending_ul_data=%d, bsr=%s\n",
pending_data,
pending_ul_data,
lch_handler.get_bsr_text().c_str());
}
return pending_data;
}
// Private lock-free implementation
uint32_t sched_ue::get_pending_ul_old_data_unlocked(uint32_t cc_idx)
{
uint32_t pending_data = 0;
for (auto& h : carriers[cc_idx].harq_ent.ul_harq_procs()) {
pending_data += h.get_pending_data();
}
return pending_data;
}
uint32_t sched_ue::get_required_prb_ul(uint32_t cc_idx, uint32_t req_bytes)
{
return carriers[cc_idx].get_required_prb_ul(req_bytes);
}
bool sched_ue::is_sr_triggered()
{
return sr;
}
/* Gets HARQ process with oldest pending retx */
dl_harq_proc* sched_ue::get_pending_dl_harq(uint32_t tti_tx_dl, uint32_t ue_cc_idx)
{
if (ue_cc_idx < carriers.size() and carriers[ue_cc_idx].cc_state() == cc_st::active) {
return carriers[ue_cc_idx].harq_ent.get_pending_dl_harq(tti_tx_dl);
}
return nullptr;
}
dl_harq_proc* sched_ue::get_empty_dl_harq(uint32_t tti_tx_dl, uint32_t ue_cc_idx)
{
if (ue_cc_idx < carriers.size() and carriers[ue_cc_idx].cc_state() == cc_st::active) {
return carriers[ue_cc_idx].harq_ent.get_empty_dl_harq(tti_tx_dl);
}
return nullptr;
}
ul_harq_proc* sched_ue::get_ul_harq(uint32_t tti_tx_ul, uint32_t ue_cc_idx)
{
if (ue_cc_idx < carriers.size() and carriers[ue_cc_idx].cc_state() == cc_st::active) {
return carriers[ue_cc_idx].harq_ent.get_ul_harq(tti_tx_ul);
}
return nullptr;
}
const dl_harq_proc& sched_ue::get_dl_harq(uint32_t idx, uint32_t ue_cc_idx) const
{
return carriers[ue_cc_idx].harq_ent.dl_harq_procs()[idx];
}
std::pair<bool, uint32_t> sched_ue::get_active_cell_index(uint32_t enb_cc_idx) const
{
auto it = std::find_if(
cfg.supported_cc_list.begin(),
cfg.supported_cc_list.end(),
[enb_cc_idx](const sched_interface::ue_cfg_t::cc_cfg_t& u) { return u.enb_cc_idx == enb_cc_idx and u.active; });
if (it != cfg.supported_cc_list.end()) {
uint32_t ue_cc_idx = std::distance(cfg.supported_cc_list.begin(), it);
return {carriers[ue_cc_idx].cc_state() == cc_st::active, ue_cc_idx};
}
return {false, std::numeric_limits<uint32_t>::max()};
}
uint32_t sched_ue::get_aggr_level(uint32_t ue_cc_idx, uint32_t nof_bits)
{
return carriers[ue_cc_idx].get_aggr_level(nof_bits);
}
void sched_ue::finish_tti(const tti_params_t& tti_params, uint32_t enb_cc_idx)
{
cc_sched_ue* c = find_ue_carrier(enb_cc_idx);
if (c != nullptr) {
// Check that scell state needs to change
c->finish_tti(current_tti);
}
}
srslte_dci_format_t sched_ue::get_dci_format()
{
srslte_dci_format_t ret = SRSLTE_DCI_FORMAT1;
if (phy_config_dedicated_enabled) {
/* TODO: Assumes UE-Specific Search Space (Not common) */
switch (cfg.dl_ant_info.tx_mode) {
case sched_interface::ant_info_ded_t::tx_mode_t::tm1:
case sched_interface::ant_info_ded_t::tx_mode_t::tm2:
ret = SRSLTE_DCI_FORMAT1;
break;
case sched_interface::ant_info_ded_t::tx_mode_t::tm3:
ret = SRSLTE_DCI_FORMAT2A;
break;
case sched_interface::ant_info_ded_t::tx_mode_t::tm4:
ret = SRSLTE_DCI_FORMAT2;
break;
case sched_interface::ant_info_ded_t::tx_mode_t::tm5:
case sched_interface::ant_info_ded_t::tx_mode_t::tm6:
case sched_interface::ant_info_ded_t::tx_mode_t::tm7:
case sched_interface::ant_info_ded_t::tx_mode_t::tm8_v920:
default:
Warning("Incorrect transmission mode (rnti=%04x; tm=%d)\n", rnti, static_cast<int>(cfg.dl_ant_info.tx_mode));
}
}
return ret;
}
sched_dci_cce_t* sched_ue::get_locations(uint32_t enb_cc_idx, uint32_t cfi, uint32_t sf_idx)
{
if (cfi > 0 && cfi <= 3) {
return &carriers[get_active_cell_index(enb_cc_idx).second].dci_locations[cfi - 1][sf_idx];
} else {
Error("SCHED: Invalid CFI=%d\n", cfi);
return &carriers[get_active_cell_index(enb_cc_idx).second].dci_locations[0][sf_idx];
}
}
cc_sched_ue* sched_ue::find_ue_carrier(uint32_t enb_cc_idx)
{
auto it = std::find_if(carriers.begin(), carriers.end(), [enb_cc_idx](const cc_sched_ue& c) {
return c.get_cell_cfg()->enb_cc_idx == enb_cc_idx;
});
return it != carriers.end() ? &(*it) : nullptr;
}
int cc_sched_ue::cqi_to_tbs(uint32_t nof_prb, uint32_t nof_re, bool use_tbs_index_alt, bool is_ul, uint32_t* mcs)
{
uint32_t cqi = is_ul ? ul_cqi : dl_cqi;
uint32_t max_mcs = is_ul ? max_mcs_ul : (cfg->use_tbs_index_alt) ? max_mcs_dl_alt : max_mcs_dl;
uint32_t max_Qm = is_ul and not ul_64qam_enabled ? 4 : 6; //< TODO: Allow PUSCH 64QAM
// Take the upper bound code-rate
float max_coderate = srslte_cqi_to_coderate(cqi < 15 ? cqi + 1 : 15);
int sel_mcs = max_mcs + 1;
float coderate = 99;
int tbs = 0;
uint32_t Qm = 0;
do {
sel_mcs--;
uint32_t tbs_idx = srslte_ra_tbs_idx_from_mcs(sel_mcs, use_tbs_index_alt, is_ul);
tbs = srslte_ra_tbs_from_idx(tbs_idx, nof_prb);
coderate = srslte_coderate(tbs, nof_re);
srslte_mod_t mod =
(is_ul) ? srslte_ra_ul_mod_from_mcs(sel_mcs) : srslte_ra_dl_mod_from_mcs(sel_mcs, use_tbs_index_alt);
Qm = SRSLTE_MIN(max_Qm, srslte_mod_bits_x_symbol(mod));
} while (sel_mcs > 0 && coderate > SRSLTE_MIN(max_coderate, 0.930 * Qm));
if (mcs != nullptr) {
*mcs = (uint32_t)sel_mcs;
}
// If coderate > SRSLTE_MIN(max_coderate, 0.930 * Qm) we should set TBS=0. We don't because it's not correctly
// handled by the scheduler, but we might be scheduling undecodable codewords at very low SNR
return tbs;
}
/************************************************************************************************
* sched_ue::sched_ue_carrier
***********************************************************************************************/
cc_sched_ue::cc_sched_ue(const sched_interface::ue_cfg_t& cfg_,
const sched_cell_params_t& cell_cfg_,
uint16_t rnti_,
uint32_t ue_cc_idx_,
tti_point current_tti) :
cell_params(&cell_cfg_),
rnti(rnti_),
log_h(srslte::logmap::get("MAC ")),
ue_cc_idx(ue_cc_idx_),
last_tti(current_tti),
harq_ent(SCHED_MAX_HARQ_PROC, SCHED_MAX_HARQ_PROC)
{
dl_cqi_rx = false;
dl_cqi = (ue_cc_idx == 0) ? cell_params->cfg.initial_dl_cqi : 0;
set_cfg(cfg_);
// set max mcs
max_mcs_ul = cell_params->sched_cfg->pusch_max_mcs >= 0 ? cell_params->sched_cfg->pusch_max_mcs : 28;
max_mcs_dl = cell_params->sched_cfg->pdsch_max_mcs >= 0 ? cell_params->sched_cfg->pdsch_max_mcs : 28;
max_mcs_dl_alt =
cell_params->sched_cfg->pdsch_max_mcs >= 0 ? SRSLTE_MIN(cell_params->sched_cfg->pdsch_max_mcs, 27) : 27;
max_aggr_level = cell_params->sched_cfg->max_aggr_level >= 0 ? cell_params->sched_cfg->max_aggr_level : 3;
// set fixed mcs
fixed_mcs_dl = cell_params->sched_cfg->pdsch_mcs;
fixed_mcs_ul = cell_params->sched_cfg->pusch_mcs;
// Generate allowed CCE locations
for (int cfi = 0; cfi < 3; cfi++) {
for (int sf_idx = 0; sf_idx < 10; sf_idx++) {
sched_utils::generate_cce_location(cell_params->regs.get(), &dci_locations[cfi][sf_idx], cfi + 1, sf_idx, rnti);
}
}
}
void cc_sched_ue::reset()
{
dl_ri = 0;
dl_ri_tti = 0;
dl_pmi = 0;
dl_pmi_tti = 0;
dl_cqi = 1;
dl_cqi_tti = 0;
ul_cqi = 1;
ul_cqi_tti = 0;
harq_ent.reset();
}
void cc_sched_ue::set_cfg(const sched_interface::ue_cfg_t& cfg_)
{
cfg = &cfg_;
cfg_tti = last_tti;
// Config HARQ processes
harq_ent.set_cfg(cfg->maxharq_tx);
if (ue_cc_idx == 0) {
// PCell is always active
cc_state_ = cc_st::active;
} else {
switch (cc_state()) {
case cc_st::activating:
case cc_st::active:
if (not cfg->supported_cc_list[ue_cc_idx].active) {
cc_state_ = cc_st::deactivating;
log_h->info("SCHED: Deactivating rnti=0x%x, SCellIndex=%d...\n", rnti, ue_cc_idx);
}
break;
case cc_st::deactivating:
case cc_st::idle:
if (cfg->supported_cc_list[ue_cc_idx].active) {
cc_state_ = cc_st::activating;
dl_cqi_rx = false;
dl_cqi = 0;
log_h->info("SCHED: Activating rnti=0x%x, SCellIndex=%d...\n", rnti, ue_cc_idx);
}
break;
default:
break;
}
}
}
void cc_sched_ue::finish_tti(srslte::tti_point tti_rx)
{
last_tti = tti_point{tti_rx};
// reset PIDs with pending data or blocked
harq_ent.reset_pending_data(last_tti);
// Check if cell state needs to be updated
if (ue_cc_idx > 0 and cc_state_ == cc_st::deactivating) {
// wait for all ACKs to be received before completely deactivating SCell
if (last_tti > srslte::to_tx_dl_ack(cfg_tti)) {
cc_state_ = cc_st::idle;
reset();
}
}
}
/* Find lowest DCI aggregation level supported by the UE spectral efficiency */
uint32_t cc_sched_ue::get_aggr_level(uint32_t nof_bits)
{
uint32_t l = 0;
float max_coderate = srslte_cqi_to_coderate(dl_cqi);
float coderate = 99;
float factor = 1.5;
uint32_t l_max = 3;
if (cell_params->nof_prb() == 6) {
factor = 1.0;
l_max = 2;
}
l_max = SRSLTE_MIN(max_aggr_level, l_max);
do {
coderate = srslte_pdcch_coderate(nof_bits, l);
l++;
} while (l < l_max && factor * coderate > max_coderate);
Debug("SCHED: CQI=%d, l=%d, nof_bits=%d, coderate=%.2f, max_coderate=%.2f\n",
dl_cqi,
l,
nof_bits,
coderate,
max_coderate);
return l;
}
/* In this scheduler we tend to use all the available bandwidth and select the MCS
* that approximates the minimum between the capacity and the requested rate
*/
int cc_sched_ue::alloc_tbs(uint32_t nof_prb, uint32_t nof_re, uint32_t req_bytes, bool is_ul, int* mcs)
{
uint32_t sel_mcs = 0;
// TODO: Compute real spectral efficiency based on PUSCH-UCI configuration
int tbs_bytes = cqi_to_tbs(nof_prb, nof_re, cfg->use_tbs_index_alt, is_ul, &sel_mcs) / 8;
/* If less bytes are requested, lower the MCS */
if (tbs_bytes > (int)req_bytes && req_bytes > 0) {
int req_tbs_idx = srslte_ra_tbs_to_table_idx(req_bytes * 8, nof_prb);
int req_mcs = srslte_ra_mcs_from_tbs_idx(req_tbs_idx, cfg->use_tbs_index_alt, is_ul);
if (req_mcs < (int)sel_mcs) {
sel_mcs = req_mcs;
tbs_bytes = srslte_ra_tbs_from_idx(req_tbs_idx, nof_prb) / 8;
}
}
// Avoid the unusual case n_prb=1, mcs=6 tbs=328 (used in voip)
if (nof_prb == 1 && sel_mcs == 6) {
sel_mcs--;
uint32_t tbs_idx = srslte_ra_tbs_idx_from_mcs(sel_mcs, cfg->use_tbs_index_alt, is_ul);
tbs_bytes = srslte_ra_tbs_from_idx(tbs_idx, nof_prb) / 8;
}
if (mcs != nullptr && tbs_bytes >= 0) {
*mcs = (int)sel_mcs;
}
return tbs_bytes;
}
int cc_sched_ue::alloc_tbs_dl(uint32_t nof_prb, uint32_t nof_re, uint32_t req_bytes, int* mcs)
{
return alloc_tbs(nof_prb, nof_re, req_bytes, false, mcs);
}
int cc_sched_ue::alloc_tbs_ul(uint32_t nof_prb, uint32_t nof_re, uint32_t req_bytes, int* mcs)
{
return alloc_tbs(nof_prb, nof_re, req_bytes, true, mcs);
}
int cc_sched_ue::get_required_prb_dl(uint32_t req_bytes, uint32_t nof_ctrl_symbols)
{
int mcs = 0;
uint32_t nof_re = 0;
int tbs = 0;
uint32_t nbytes = 0;
uint32_t n;
for (n = 0; n < cell_params->nof_prb() and nbytes < req_bytes; ++n) {
nof_re = srslte_ra_dl_approx_nof_re(&cell_params->cfg.cell, n + 1, nof_ctrl_symbols);
if (fixed_mcs_dl < 0 or not dl_cqi_rx) {
tbs = alloc_tbs_dl(n + 1, nof_re, 0, &mcs);
} else {
tbs = srslte_ra_tbs_from_idx(srslte_ra_tbs_idx_from_mcs(fixed_mcs_dl, cfg->use_tbs_index_alt, false), n + 1) / 8;
}
if (tbs > 0) {
nbytes = tbs;
} else if (tbs < 0) {
return 0;
}
}
return (nbytes >= req_bytes) ? n : -1;
}
uint32_t cc_sched_ue::get_required_prb_ul(uint32_t req_bytes)
{
int mcs = 0;
uint32_t nbytes = 0;
uint32_t N_srs = 0;
uint32_t n = 0;
if (req_bytes == 0) {
return 0;
}
uint32_t last_valid_n = 0;
for (n = 1; n < cell_params->nof_prb() && nbytes < req_bytes + 4; n++) {
uint32_t nof_re = (2 * (SRSLTE_CP_NSYMB(cell_params->cfg.cell.cp) - 1) - N_srs) * n * SRSLTE_NRE;
int tbs = 0;
if (fixed_mcs_ul < 0) {
tbs = alloc_tbs_ul(n, nof_re, 0, &mcs);
} else {
tbs = srslte_ra_tbs_from_idx(srslte_ra_tbs_idx_from_mcs(fixed_mcs_ul, false, true), n) / 8;
}
if (tbs > 0) {
nbytes = tbs;
last_valid_n = n;
}
}
if (last_valid_n > 0) {
if (n != last_valid_n) {
n = last_valid_n;
}
while (!srslte_dft_precoding_valid_prb(n) && n <= cell_params->nof_prb()) {
n++;
}
return n;
} else {
// This should never happen. Just in case, return 0 PRB and handle it later
log_h->error("SCHED: Could not obtain any valid number of PRB for an uplink allocation\n");
return 0;
}
}
void cc_sched_ue::set_dl_cqi(uint32_t tti_tx_dl, uint32_t dl_cqi_)
{
dl_cqi = dl_cqi_;
dl_cqi_tti = tti_tx_dl;
dl_cqi_rx = dl_cqi_rx or dl_cqi > 0;
if (ue_cc_idx > 0 and cc_state_ == cc_st::activating and dl_cqi_rx) {
// Wait for SCell to receive a positive CQI before activating it
cc_state_ = cc_st::active;
log_h->info("SCHED: SCell index=%d is now active\n", ue_cc_idx);
}
}
/*******************************************************
*
* Logical Channel Management
*
*******************************************************/
const char* to_string(sched_interface::ue_bearer_cfg_t::direction_t dir)
{
switch (dir) {
case sched_interface::ue_bearer_cfg_t::IDLE:
return "idle";
case sched_interface::ue_bearer_cfg_t::BOTH:
return "bi-dir";
case sched_interface::ue_bearer_cfg_t::DL:
return "DL";
case sched_interface::ue_bearer_cfg_t::UL:
return "UL";
default:
return "unrecognized direction";
}
}
void lch_manager::set_cfg(const sched_interface::ue_cfg_t& cfg)
{
for (uint32_t lcid = 0; lcid < sched_interface::MAX_LC; lcid++) {
config_lcid(lcid, cfg.ue_bearers[lcid]);
}
}
void lch_manager::new_tti()
{
prio_idx++;
for (uint32_t lcid = 0; lcid < sched_interface::MAX_LC; ++lcid) {
if (is_bearer_active(lcid)) {
if (lch[lcid].cfg.pbr != pbr_infinity) {
lch[lcid].Bj = std::min(lch[lcid].Bj + (int)(lch[lcid].cfg.pbr * tti_duration_ms), lch[lcid].bucket_size);
}
}
}
}
void lch_manager::config_lcid(uint32_t lc_id, const sched_interface::ue_bearer_cfg_t& bearer_cfg)
{
if (lc_id >= sched_interface::MAX_LC) {
Warning("Adding bearer with invalid logical channel id=%d\n", lc_id);
return;
}
if (bearer_cfg.group >= sched_interface::MAX_LC_GROUP) {
Warning("Adding bearer with invalid logical channel group id=%d\n", bearer_cfg.group);
return;
}
// update bearer config
bool is_equal = memcmp(&bearer_cfg, &lch[lc_id].cfg, sizeof(bearer_cfg)) == 0;
if (not is_equal) {
lch[lc_id].cfg = bearer_cfg;
if (lch[lc_id].cfg.pbr == pbr_infinity) {
lch[lc_id].bucket_size = std::numeric_limits<int>::max();
lch[lc_id].Bj = std::numeric_limits<int>::max();
} else {
lch[lc_id].bucket_size = lch[lc_id].cfg.bsd * lch[lc_id].cfg.pbr;
lch[lc_id].Bj = 0;
}
Info("SCHED: bearer configured: lc_id=%d, mode=%s, prio=%d\n",
lc_id,
to_string(lch[lc_id].cfg.direction),
lch[lc_id].cfg.priority);
}
}
void lch_manager::ul_bsr(uint8_t lcg_id, uint32_t bsr)
{
if (lcg_id >= sched_interface::MAX_LC_GROUP) {
Warning("The provided logical channel group id=%d is not valid\n", lcg_id);
return;
}
lcg_bsr[lcg_id] = bsr;
Debug("SCHED: bsr=%d, lcg_id=%d, bsr=%s\n", bsr, lcg_id, get_bsr_text().c_str());
}
void lch_manager::ul_buffer_add(uint8_t lcid, uint32_t bytes)
{
if (lcid >= sched_interface::MAX_LC) {
Warning("The provided lcid=%d is not valid\n", lcid);
return;
}
lcg_bsr[lch[lcid].cfg.group] += bytes;
Debug("SCHED: UL buffer update=%d, lcg_id=%d, bsr=%s\n", bytes, lch[lcid].cfg.group, get_bsr_text().c_str());
}
void lch_manager::dl_buffer_state(uint8_t lcid, uint32_t tx_queue, uint32_t retx_queue)
{
if (lcid >= sched_interface::MAX_LC) {
Warning("The provided lcid=%d is not valid\n", lcid);
return;
}
lch[lcid].buf_retx = retx_queue;
lch[lcid].buf_tx = tx_queue;
Debug("SCHED: DL lcid=%d buffer_state=%d,%d\n", lcid, tx_queue, retx_queue);
}
int lch_manager::get_max_prio_lcid() const
{
int min_prio_val = std::numeric_limits<int>::max(), prio_lcid = -1;
// Prioritize retxs
for (uint32_t lcid = 0; lcid < MAX_LC; ++lcid) {
if (get_dl_retx(lcid) > 0 and lch[lcid].cfg.priority < min_prio_val) {
min_prio_val = lch[lcid].cfg.priority;
prio_lcid = lcid;
}
}
if (prio_lcid >= 0) {
return prio_lcid;
}
// Select lcid with new txs using Bj
for (uint32_t lcid = 0; lcid < MAX_LC; ++lcid) {
if (get_dl_tx(lcid) > 0 and lch[lcid].Bj > 0 and lch[lcid].cfg.priority < min_prio_val) {
min_prio_val = lch[lcid].cfg.priority;
prio_lcid = lcid;
}
}
if (prio_lcid >= 0) {
return prio_lcid;
}
// Disregard Bj
size_t nof_lcids = 0;
std::array<uint32_t, MAX_LC> chosen_lcids = {};
for (uint32_t lcid = 0; lcid < MAX_LC; ++lcid) {
if (get_dl_tx_total(lcid) > 0) {
if (lch[lcid].cfg.priority < min_prio_val) {
min_prio_val = lch[lcid].cfg.priority;
chosen_lcids[0] = lcid;
nof_lcids = 1;
} else if (lch[lcid].cfg.priority == min_prio_val) {
chosen_lcids[nof_lcids++] = lcid;
}
}
}
// logical chanels with equal priority should be served equally
if (nof_lcids > 0) {
prio_lcid = chosen_lcids[prio_idx % nof_lcids];
}
return prio_lcid;
}
/// Allocates first available RLC PDU
int lch_manager::alloc_rlc_pdu(sched_interface::dl_sched_pdu_t* rlc_pdu, int rem_bytes)
{
int alloc_bytes = 0;
int lcid = get_max_prio_lcid();
if (lcid < 0) {
return alloc_bytes;
}
// try first to allocate retxs
alloc_bytes = alloc_retx_bytes(lcid, rem_bytes);
// if no retx alloc, try newtx
if (alloc_bytes == 0) {
alloc_bytes = alloc_tx_bytes(lcid, rem_bytes);
}
if (alloc_bytes > 0) {
rlc_pdu->nbytes = alloc_bytes;
rlc_pdu->lcid = lcid;
Debug("SCHED: Allocated lcid=%d, nbytes=%d, tbs_bytes=%d\n", rlc_pdu->lcid, rlc_pdu->nbytes, rem_bytes);
}
return alloc_bytes;
}
int lch_manager::alloc_retx_bytes(uint8_t lcid, uint32_t rem_bytes)
{
int alloc = std::min((int)rem_bytes, get_dl_retx(lcid));
lch[lcid].buf_retx -= alloc;
return alloc;
}
int lch_manager::alloc_tx_bytes(uint8_t lcid, uint32_t rem_bytes)
{
int alloc = std::min((int)rem_bytes, get_dl_tx(lcid));
lch[lcid].buf_tx -= alloc;
if (alloc > 0 and lch[lcid].cfg.pbr != pbr_infinity) {
// Update Bj
lch[lcid].Bj -= alloc;
}
return alloc;
}
bool lch_manager::is_bearer_active(uint32_t lcid) const
{
return lch[lcid].cfg.direction != sched_interface::ue_bearer_cfg_t::IDLE;
}
bool lch_manager::is_bearer_ul(uint32_t lcid) const
{
return is_bearer_active(lcid) and lch[lcid].cfg.direction != sched_interface::ue_bearer_cfg_t::DL;
}
bool lch_manager::is_bearer_dl(uint32_t lcid) const
{
return is_bearer_active(lcid) and lch[lcid].cfg.direction != sched_interface::ue_bearer_cfg_t::UL;
}
int lch_manager::get_dl_tx(uint32_t lcid) const
{
return is_bearer_dl(lcid) ? lch[lcid].buf_tx : 0;
}
int lch_manager::get_dl_retx(uint32_t lcid) const
{
return is_bearer_dl(lcid) ? lch[lcid].buf_retx : 0;
}
int lch_manager::get_bsr(uint32_t lcid) const
{
return is_bearer_ul(lcid) ? lcg_bsr[lch[lcid].cfg.group] : 0;
}
std::string lch_manager::get_bsr_text() const
{
std::stringstream ss;
ss << "{" << lcg_bsr[0] << ", " << lcg_bsr[1] << ", " << lcg_bsr[2] << ", " << lcg_bsr[3] << "}";
return ss.str();
}
} // namespace srsenb
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