SRSUE: avoid negative SR transmission in NR

lib/include/srsran/phy/phch/uci_cfg_nr.h

@@ -35,12 +35,11 @@
  * @brief Uplink Control Information bits configuration for PUCCH transmission
  */
 typedef struct {
-  uint16_t rnti;                ///< RNTI
+  uint16_t rnti;           ///< RNTI
-  uint32_t resource_id;         ///< PUCCH resource indicator field in the DCI format 1_0 or DCI format 1_1
+  uint32_t resource_id;    ///< PUCCH resource indicator field in the DCI format 1_0 or DCI format 1_1
-  uint32_t n_cce_0;             ///< index of a first CCE for the PDCCH reception
+  uint32_t n_cce_0;        ///< index of a first CCE for the PDCCH reception
-  uint32_t N_cce;               ///< number of CCEs in a CORESET of a PDCCH reception with DCI format 1_0 or 1_1
+  uint32_t N_cce;          ///< number of CCEs in a CORESET of a PDCCH reception with DCI format 1_0 or 1_1
-  uint32_t sr_resource_id;      ///< Scheduling request resource identifier, only valid if positive SR
+  uint32_t sr_resource_id; ///< Scheduling request resource identifier, only valid if positive SR
-  bool     sr_positive_present; ///< Set to true if there is at least one positive SR
 } srsran_uci_nr_pucch_cfg_t;
 
 /**
@@ -70,6 +69,7 @@ typedef struct SRSRAN_API {
   /// Common Parameters
   srsran_harq_ack_cfg_t   ack;                            ///< HARQ-ACK configuration
   uint32_t                o_sr;                           ///< Number of SR bits
+  bool                    sr_positive_present;            ///< Set to true if there is at least one positive SR
   srsran_csi_report_cfg_t csi[SRSRAN_CSI_MAX_NOF_REPORT]; ///< CSI report configuration
   uint32_t                nof_csi;                        ///< Number of CSI reports
   union {

lib/src/phy/phch/ra_ul_nr.c

@@ -530,7 +530,7 @@ int srsran_ra_ul_nr_pucch_resource(const srsran_pucch_nr_hl_cfg_t* pucch_cfg,
   // - At least one positive SR
   // - up to 2 HARQ-ACK
   // - No CSI report
-  if (uci_cfg->pucch.sr_positive_present > 0 && uci_cfg->ack.count <= SRSRAN_PUCCH_NR_FORMAT1_MAX_NOF_BITS &&
+  if (uci_cfg->sr_positive_present > 0 && uci_cfg->ack.count <= SRSRAN_PUCCH_NR_FORMAT1_MAX_NOF_BITS &&
       uci_cfg->nof_csi == 0) {
     uint32_t sr_resource_id = uci_cfg->pucch.sr_resource_id;
     if (sr_resource_id >= SRSRAN_PUCCH_MAX_NOF_SR_RESOURCES) {

lib/src/phy/phch/uci_nr.c

@@ -980,7 +980,16 @@ uint32_t srsran_uci_nr_total_bits(const srsran_uci_cfg_nr_t* uci_cfg)
     return 0;
   }
 
-  return uci_cfg->ack.count + uci_cfg->o_sr + srsran_csi_part1_nof_bits(uci_cfg->csi, uci_cfg->nof_csi);
+  uint32_t o_csi = srsran_csi_part1_nof_bits(uci_cfg->csi, uci_cfg->nof_csi);
+
+  // According to 38.213 9.2.4 UE procedure for reporting SR
+  // The UE transmits a PUCCH in the PUCCH resource for the corresponding SR configuration only when the UE transmits a
+  // positive SR
+  if (uci_cfg->ack.count == 0 && o_csi == 0 && !uci_cfg->sr_positive_present) {
+    return 0;
+  }
+
+  return uci_cfg->ack.count + uci_cfg->o_sr + o_csi;
 }
 
 uint32_t srsran_uci_nr_info(const srsran_uci_data_nr_t* uci_data, char* str, uint32_t str_len)

srsue/hdr/phy/nr/state.h

@@ -316,7 +316,7 @@ public:
     }
 
     // Initialise counters
-    uint32_t sr_count_all      = (uint32_t)n;
+    uint32_t sr_count_all      = (uint32_t)n; // Number of opportunities in this TTI
     uint32_t sr_count_positive = 0;
 
     // Iterate all opportunities and check if there is a pending SR
@@ -333,10 +333,10 @@ public:
     }
 
     // Configure SR fields in UCI data
-    uci_data.cfg.pucch.sr_resource_id      = sr_resource_id[0];
+    uci_data.cfg.pucch.sr_resource_id = sr_resource_id[0];
-    uci_data.cfg.o_sr                      = srsran_ra_ul_nr_nof_sr_bits(sr_count_all);
+    uci_data.cfg.o_sr                 = srsran_ra_ul_nr_nof_sr_bits(sr_count_all);
-    uci_data.cfg.pucch.sr_positive_present = sr_count_positive > 0;
+    uci_data.cfg.sr_positive_present  = sr_count_positive > 0;
-    uci_data.value.sr                      = sr_count_positive;
+    uci_data.value.sr                 = sr_count_positive;
   }
 
   void get_periodic_csi(const uint32_t& tti, srsran_uci_data_nr_t& uci_data)

srsue/src/phy/nr/cc_worker.cc

@@ -538,7 +538,7 @@ bool cc_worker::work_ul()
   }
 
   // Add SR to UCI data only if there is no UL grant!
-  if (!has_ul_ack) {
+  if (not has_pusch_grant) {
     phy.get_pending_sr(ul_slot_cfg.idx, uci_data);
   }