sched: added checks for localized RBG assignment in case of DCI format1A

srsenb/hdr/stack/mac/sched_common.h

@@ -88,13 +88,14 @@ using prbmask_t = srslte::bounded_bitset<100, true>;
 struct prb_interval;
 struct rbg_interval : public srslte::interval<uint32_t> {
   using interval::interval;
+  rbg_interval(srslte::interval<uint32_t> i) : interval(i) {}
   static rbg_interval rbgmask_to_rbgs(const rbgmask_t& mask);
 };
 
 //! Struct to express a {min,...,max} range of PRBs
 struct prb_interval : public srslte::interval<uint32_t> {
   using interval::interval;
-
+  prb_interval(srslte::interval<uint32_t> i) : interval(i) {}
   static prb_interval rbgs_to_prbs(const rbg_interval& rbgs, uint32_t cell_nof_prb);
   static prb_interval riv_to_prbs(uint32_t riv, uint32_t nof_prbs, int nof_vrbs = -1);
 };

srsenb/hdr/stack/mac/sched_grid.h

@@ -36,7 +36,10 @@ struct alloc_outcome_t {
     NOF_RB_INVALID,
     PUCCH_COLLISION,
     MEASGAP_COLLISION,
-    ALREADY_ALLOC
+    ALREADY_ALLOC,
+    NO_DATA,
+    INVALID_PRBMASK,
+    INVALID_CARRIER
   };
   result_enum result = ERROR;
   alloc_outcome_t()  = default;

srsenb/hdr/stack/mac/sched_helpers.h

@@ -142,6 +142,12 @@ uint32_t get_aggr_level(uint32_t nof_bits,
                         uint32_t cell_nof_prb,
                         bool     use_tbs_index_alt);
 
+/*******************************************************
+ *              RB mask helper functions
+ *******************************************************/
+
+bool is_contiguous(const rbgmask_t& mask);
+
 /*******************************************************
  *          sched_interface helper functions
  *******************************************************/

srsenb/hdr/stack/mac/schedulers/sched_base.h

@@ -35,12 +35,13 @@ protected:
 /**************** Helper methods ****************/
 
 /**
- * Finds a bitmask of available RBG resources
- * @param L Size of the requested DL RBGs
- * @param current_mask input RBG bitmask where to search for available RBGs
- * @return bitmask of found RBGs
+ * Finds a bitmask of available RBG resources for a given UE in a greedy fashion
+ * @param ue UE being allocated
+ * @param enb_cc_idx carrier index
+ * @param current_mask bitmask of occupied RBGs, where to search for available RBGs
+ * @return bitmask of found RBGs. If a valid mask wasn't found, bitmask::size() == 0
  */
-rbgmask_t find_available_dl_rbgs(uint32_t L, const rbgmask_t& current_mask);
+rbgmask_t compute_user_rbgmask_greedy(sched_ue& ue, uint32_t enb_cc_idx, const rbgmask_t& current_mask);
 
 /**
  * Finds a range of L contiguous PRBs that are empty
@@ -57,6 +58,8 @@ const ul_harq_proc* get_ul_newtx_harq(sched_ue& user, sf_sched* tti_sched);
 
 /// Helper methods to allocate resources in subframe
 alloc_outcome_t try_dl_retx_alloc(sf_sched& tti_sched, sched_ue& ue, const dl_harq_proc& h);
+alloc_outcome_t
+                try_dl_newtx_alloc_greedy(sf_sched& tti_sched, sched_ue& ue, const dl_harq_proc& h, rbgmask_t* result_mask = nullptr);
 alloc_outcome_t try_ul_retx_alloc(sf_sched& tti_sched, sched_ue& ue, const ul_harq_proc& h);
 
 } // namespace srsenb

srsenb/src/stack/mac/sched_grid.cc

@@ -38,6 +38,14 @@ const char* alloc_outcome_t::to_string() const
       return "measgap_collision";
     case ALREADY_ALLOC:
       return "already allocated";
+    case NO_DATA:
+      return "no pending data to allocate";
+    case INVALID_PRBMASK:
+      return "invalid rbg mask";
+    case INVALID_CARRIER:
+      return "invalid eNB carrier";
+    default:
+      break;
   }
   return "unknown error";
 }
@@ -770,7 +778,7 @@ alloc_outcome_t sf_sched::alloc_dl_user(sched_ue* user, const rbgmask_t& user_ma
 
   auto* cc = user->find_ue_carrier(cc_cfg->enb_cc_idx);
   if (cc == nullptr or cc->cc_state() != cc_st::active) {
-    return alloc_outcome_t::ERROR;
+    return alloc_outcome_t::INVALID_CARRIER;
   }
   if (not user->pdsch_enabled(srslte::tti_point{get_tti_rx()}, cc_cfg->enb_cc_idx)) {
     return alloc_outcome_t::MEASGAP_COLLISION;
@@ -782,11 +790,17 @@ alloc_outcome_t sf_sched::alloc_dl_user(sched_ue* user, const rbgmask_t& user_ma
     // It is newTx
     rbg_interval r = user->get_required_dl_rbgs(cc_cfg->enb_cc_idx);
     if (r.start() > user_mask.count()) {
-      logger.warning("The number of RBGs allocated to rnti=0x%x will force segmentation", user->get_rnti());
+      logger.warning("SCHED: The number of RBGs allocated to rnti=0x%x will force segmentation", user->get_rnti());
       return alloc_outcome_t::NOF_RB_INVALID;
     }
   }
 
+  srslte_dci_format_t dci_format = user->get_dci_format();
+  if (dci_format == SRSLTE_DCI_FORMAT1A and not is_contiguous(user_mask)) {
+    logger.warning("SCHED: Can't use distributed RBGs for DCI format 1A");
+    return alloc_outcome_t::INVALID_PRBMASK;
+  }
+
   // Check if there is space in the PUCCH for HARQ ACKs
   const sched_interface::ue_cfg_t& ue_cfg    = user->get_ue_cfg();
   std::bitset<SRSLTE_MAX_CARRIERS> scells    = user->scell_activation_mask();

srsenb/src/stack/mac/sched_helpers.cc

@@ -182,6 +182,11 @@ prb_interval prb_interval::riv_to_prbs(uint32_t riv, uint32_t nof_prbs, int nof_
   return {rb_start, rb_start + l_crb};
 }
 
+bool is_contiguous(const rbgmask_t& mask)
+{
+  return rbg_interval::rbgmask_to_rbgs(mask).length() == mask.count();
+}
+
 /*******************************************************
  *                 Sched Params
  *******************************************************/

srsenb/src/stack/mac/schedulers/sched_base.cc

@@ -14,16 +14,42 @@
 
 namespace srsenb {
 
-rbgmask_t find_available_dl_rbgs(uint32_t max_rbgs, const rbgmask_t& current_mask)
+/*********************************
+ * Common UL/DL Helper methods
+ ********************************/
+
+template <size_t N>
+srslte::interval<uint32_t> find_contiguous_interval(const srslte::bounded_bitset<N, true>& in_mask, uint32_t max_size)
 {
-  if (max_rbgs == 0 or current_mask.all()) {
-    return rbgmask_t{};
+  srslte::interval<uint32_t> interv, max_interv;
+
+  for (uint32_t n = 0; n < in_mask.size() and interv.length() < max_size; n++) {
+    if (not in_mask.test(n) and interv.empty()) {
+      // new interval
+      interv.set(n, n + 1);
+    } else if (not in_mask.test(n)) {
+      // extend current interval
+      interv.resize_by(1);
+    } else if (not interv.empty()) {
+      // reset interval
+      max_interv = interv.length() > max_interv.length() ? interv : max_interv;
+      interv     = {};
+    }
   }
-  // 1's for free rbgs
-  rbgmask_t localmask = ~(current_mask);
+  return interv.length() > max_interv.length() ? interv : max_interv;
+}
+
+/****************************
+ *    DL Helper methods
+ ***************************/
+
+rbgmask_t find_available_rb_mask(const rbgmask_t& in_mask, uint32_t max_size)
+{
+  // 1's for free RBs
+  rbgmask_t localmask = ~(in_mask);
 
   uint32_t i = 0, nof_alloc = 0;
-  for (; i < localmask.size() and nof_alloc < max_rbgs; ++i) {
+  for (; i < localmask.size() and nof_alloc < max_size; ++i) {
     if (localmask.test(i)) {
       nof_alloc++;
     }
@@ -32,42 +58,17 @@ rbgmask_t find_available_dl_rbgs(uint32_t max_rbgs, const rbgmask_t& current_mas
   return localmask;
 }
 
-prb_interval find_contiguous_ul_prbs(uint32_t L, const prbmask_t& current_mask)
+rbgmask_t compute_user_rbgmask_greedy(uint32_t max_nof_rbgs, bool is_contiguous, const rbgmask_t& current_mask)
 {
-  prb_interval prb_interv, prb_interv2;
-  for (uint32_t n = 0; n < current_mask.size() and prb_interv.length() < L; n++) {
-    if (not current_mask.test(n) and prb_interv.length() == 0) {
-      // new interval
-      prb_interv.set(n, n + 1);
-    } else if (not current_mask.test(n)) {
-      // extend current interval
-      prb_interv.resize_by(1);
-    } else if (prb_interv.length() > 0) {
-      // reset interval
-      prb_interv2 = prb_interv.length() > prb_interv2.length() ? prb_interv : prb_interv2;
-      prb_interv  = {};
-    }
+  // Allocate enough RBs that accommodate pending data
+  rbgmask_t newtx_mask(current_mask.size());
+  if (is_contiguous) {
+    rbg_interval interv = find_contiguous_interval(current_mask, max_nof_rbgs);
+    newtx_mask.fill(interv.start(), interv.stop());
+  } else {
+    newtx_mask = find_available_rb_mask(current_mask, max_nof_rbgs);
   }
-  prb_interv = prb_interv2.length() > prb_interv.length() ? prb_interv2 : prb_interv;
-  if (prb_interv.empty()) {
-    return prb_interv;
-  }
-
-  // Make sure L is allowed by SC-FDMA modulation
-  prb_interv2 = prb_interv;
-  while (not srslte_dft_precoding_valid_prb(prb_interv.length()) and prb_interv.stop() < current_mask.size() and
-         not current_mask.test(prb_interv.stop())) {
-    prb_interv.resize_by(1);
-  }
-  if (not srslte_dft_precoding_valid_prb(prb_interv.length())) {
-    // if length increase failed, try to decrease
-    prb_interv = prb_interv2;
-    prb_interv.resize_by(-1);
-    while (not srslte_dft_precoding_valid_prb(prb_interv.length()) and not prb_interv.empty()) {
-      prb_interv.resize_by(-1);
-    }
-  }
-  return prb_interv;
+  return newtx_mask;
 }
 
 int get_ue_cc_idx_if_pdsch_enabled(const sched_ue& user, sf_sched* tti_sched)
@@ -104,6 +105,87 @@ const dl_harq_proc* get_dl_newtx_harq(sched_ue& user, sf_sched* tti_sched)
   return user.get_empty_dl_harq(tti_sched->get_tti_tx_dl(), tti_sched->get_enb_cc_idx());
 }
 
+alloc_outcome_t try_dl_retx_alloc(sf_sched& tti_sched, sched_ue& ue, const dl_harq_proc& h)
+{
+  // Try to reuse the same mask
+  rbgmask_t       retx_mask = h.get_rbgmask();
+  alloc_outcome_t code      = tti_sched.alloc_dl_user(&ue, retx_mask, h.get_id());
+  if (code == alloc_outcome_t::SUCCESS or code == alloc_outcome_t::DCI_COLLISION) {
+    return code;
+  }
+
+  // If previous mask does not fit, find another with exact same number of rbgs
+  size_t nof_rbg             = retx_mask.count();
+  bool   is_contiguous_alloc = ue.get_dci_format() == SRSLTE_DCI_FORMAT1A;
+  retx_mask                  = compute_user_rbgmask_greedy(nof_rbg, is_contiguous_alloc, tti_sched.get_dl_mask());
+  if (retx_mask.count() == nof_rbg) {
+    return tti_sched.alloc_dl_user(&ue, retx_mask, h.get_id());
+  }
+  return alloc_outcome_t::RB_COLLISION;
+}
+
+alloc_outcome_t
+try_dl_newtx_alloc_greedy(sf_sched& tti_sched, sched_ue& ue, const dl_harq_proc& h, rbgmask_t* result_mask)
+{
+  if (result_mask != nullptr) {
+    *result_mask = {};
+  }
+
+  // If all RBGs are occupied, the next steps can be shortcut
+  const rbgmask_t& current_mask = tti_sched.get_dl_mask();
+  if (current_mask.all()) {
+    return alloc_outcome_t::RB_COLLISION;
+  }
+
+  // If there is no data to transmit, no need to allocate
+  rbg_interval req_rbgs = ue.get_required_dl_rbgs(tti_sched.get_enb_cc_idx());
+  if (req_rbgs.stop() == 0) {
+    return alloc_outcome_t::NO_DATA;
+  }
+
+  // Find RBG mask that accommodates pending data
+  bool      is_contiguous_alloc = ue.get_dci_format() == SRSLTE_DCI_FORMAT1A;
+  rbgmask_t newtxmask           = compute_user_rbgmask_greedy(req_rbgs.stop(), is_contiguous_alloc, current_mask);
+  if (newtxmask.none() or newtxmask.count() < req_rbgs.start()) {
+    return alloc_outcome_t::RB_COLLISION;
+  }
+
+  // empty RBGs were found. Attempt allocation
+  alloc_outcome_t ret = tti_sched.alloc_dl_user(&ue, newtxmask, h.get_id());
+  if (ret == alloc_outcome_t::SUCCESS and result_mask != nullptr) {
+    *result_mask = newtxmask;
+  }
+  return ret;
+}
+
+/*****************
+ *  UL Helpers
+ ****************/
+
+prb_interval find_contiguous_ul_prbs(uint32_t L, const prbmask_t& current_mask)
+{
+  prb_interval prb_interv = find_contiguous_interval(current_mask, L);
+  if (prb_interv.empty()) {
+    return prb_interv;
+  }
+
+  // Make sure L is allowed by SC-FDMA modulation
+  prb_interval prb_interv2 = prb_interv;
+  while (not srslte_dft_precoding_valid_prb(prb_interv.length()) and prb_interv.stop() < current_mask.size() and
+         not current_mask.test(prb_interv.stop())) {
+    prb_interv.resize_by(1);
+  }
+  if (not srslte_dft_precoding_valid_prb(prb_interv.length())) {
+    // if length increase failed, try to decrease
+    prb_interv = prb_interv2;
+    prb_interv.resize_by(-1);
+    while (not srslte_dft_precoding_valid_prb(prb_interv.length()) and not prb_interv.empty()) {
+      prb_interv.resize_by(-1);
+    }
+  }
+  return prb_interv;
+}
+
 int get_ue_cc_idx_if_pusch_enabled(const sched_ue& user, sf_sched* tti_sched, bool needs_pdcch)
 {
   // Do not allocate a user multiple times in the same tti
@@ -139,24 +221,6 @@ const ul_harq_proc* get_ul_newtx_harq(sched_ue& user, sf_sched* tti_sched)
   return h->is_empty() ? h : nullptr;
 }
 
-alloc_outcome_t try_dl_retx_alloc(sf_sched& tti_sched, sched_ue& ue, const dl_harq_proc& h)
-{
-  // Try to reuse the same mask
-  rbgmask_t       retx_mask = h.get_rbgmask();
-  alloc_outcome_t code      = tti_sched.alloc_dl_user(&ue, retx_mask, h.get_id());
-  if (code == alloc_outcome_t::SUCCESS or code == alloc_outcome_t::DCI_COLLISION) {
-    return code;
-  }
-
-  // If previous mask does not fit, find another with exact same number of rbgs
-  size_t nof_rbg = retx_mask.count();
-  retx_mask      = find_available_dl_rbgs(nof_rbg, tti_sched.get_dl_mask());
-  if (retx_mask.count() == nof_rbg) {
-    return tti_sched.alloc_dl_user(&ue, retx_mask, h.get_id());
-  }
-  return alloc_outcome_t::RB_COLLISION;
-}
-
 alloc_outcome_t try_ul_retx_alloc(sf_sched& tti_sched, sched_ue& ue, const ul_harq_proc& h)
 {
   // If can schedule the same mask, do it

srsenb/src/stack/mac/schedulers/sched_time_pf.cc

@@ -78,20 +78,13 @@ uint32_t sched_time_pf::try_dl_alloc(ue_ctxt& ue_ctxt, sched_ue& ue, sf_sched* t
       return ue_ctxt.dl_retx_h->get_tbs(0) + ue_ctxt.dl_retx_h->get_tbs(1);
     }
   }
+
+  // There is space in PDCCH and an available DL HARQ
   if (code != alloc_outcome_t::DCI_COLLISION and ue_ctxt.dl_newtx_h != nullptr) {
-    rbg_interval req_rbgs = ue.get_required_dl_rbgs(cc_cfg->enb_cc_idx);
-    // Check if there is an empty harq for the newtx
-    if (req_rbgs.stop() == 0) {
-      return 0;
-    }
-    // Allocate resources based on pending data
-    rbgmask_t newtx_mask = find_available_dl_rbgs(req_rbgs.stop(), tti_sched->get_dl_mask());
-    if (newtx_mask.count() >= req_rbgs.start()) {
-      // empty RBGs were found
-      code = tti_sched->alloc_dl_user(&ue, newtx_mask, ue_ctxt.dl_newtx_h->get_id());
-      if (code == alloc_outcome_t::SUCCESS) {
-        return ue.get_expected_dl_bitrate(cc_cfg->enb_cc_idx, newtx_mask.count()) * tti_duration_ms / 8;
-      }
+    rbgmask_t alloc_mask;
+    code = try_dl_newtx_alloc_greedy(*tti_sched, ue, *ue_ctxt.dl_newtx_h, &alloc_mask);
+    if (code == alloc_outcome_t::SUCCESS) {
+      return ue.get_expected_dl_bitrate(cc_cfg->enb_cc_idx, alloc_mask.count()) * tti_duration_ms / 8;
     }
   }
   if (code == alloc_outcome_t::DCI_COLLISION) {

srsenb/src/stack/mac/schedulers/sched_time_rr.cc

@@ -69,20 +69,13 @@ void sched_time_rr::sched_dl_newtxs(std::map<uint16_t, sched_ue>& ue_db, sf_sche
     if (user.enb_to_ue_cc_idx(cc_cfg->enb_cc_idx) < 0) {
       continue;
     }
-    const dl_harq_proc* h        = get_dl_newtx_harq(user, tti_sched);
-    rbg_interval        req_rbgs = user.get_required_dl_rbgs(cc_cfg->enb_cc_idx);
+    const dl_harq_proc* h = get_dl_newtx_harq(user, tti_sched);
     // Check if there is an empty harq for the newtx
-    if (h == nullptr or req_rbgs.stop() == 0) {
+    if (h == nullptr) {
       continue;
     }
-    // Allocate resources based on pending data
-    rbgmask_t newtx_mask = find_available_dl_rbgs(req_rbgs.stop(), tti_sched->get_dl_mask());
-    if (newtx_mask.count() >= req_rbgs.start()) {
-      // empty RBGs were found
-      alloc_outcome_t code = tti_sched->alloc_dl_user(&user, newtx_mask, h->get_id());
-      if (code == alloc_outcome_t::DCI_COLLISION) {
-        logger.info("SCHED: Couldn't find space in PDCCH for DL tx for rnti=0x%x", user.get_rnti());
-      }
+    if (try_dl_newtx_alloc_greedy(*tti_sched, user, *h) == alloc_outcome_t::DCI_COLLISION) {
+      logger.info("SCHED: Couldn't find space in PDCCH for DL tx for rnti=0x%x", user.get_rnti());
     }
   }
 }