SRSUE: Added TDD DL/UL slot detection

lib/include/srslte/interfaces/rrc_nr_interface_types.h

@@ -24,6 +24,7 @@ namespace srslte {
  **************************/
 
 struct phy_cfg_nr_t {
+  srslte_tdd_config_nr_t         tdd      = {};
   srslte_sch_hl_cfg_nr_t         pdsch    = {};
   srslte_sch_hl_cfg_nr_t         pusch    = {};
   srslte_pucch_nr_hl_cfg_t       pucch    = {};
@@ -34,9 +35,6 @@ struct phy_cfg_nr_t {
 
   phy_cfg_nr_t()
   {
-    // Default PDSCH configuration
-    pdsch.sch_cfg.mcs_table = srslte_mcs_table_256qam;
-
     // Default PRACH configuration
     prach.is_nr            = true;
     prach.config_idx       = 16;
@@ -46,6 +44,21 @@ struct phy_cfg_nr_t {
     prach.num_ra_preambles = 64;
     prach.hs_flag          = false;
 
+    // tdd-UL-DL-ConfigurationCommon
+    //    referenceSubcarrierSpacing: kHz15 (0)
+    //    pattern1
+    //        dl-UL-TransmissionPeriodicity: ms10 (7)
+    //        nrofDownlinkSlots: 7
+    //        nrofDownlinkSymbols: 6
+    //        nrofUplinkSlots: 2
+    //        nrofUplinkSymbols: 4
+    tdd.pattern1.period_ms      = 10;
+    tdd.pattern1.nof_dl_slots   = 7;
+    tdd.pattern1.nof_dl_symbols = 6;
+    tdd.pattern1.nof_ul_slots   = 2;
+    tdd.pattern1.nof_ul_symbols = 4;
+    tdd.pattern2.period_ms      = 0;
+
     // physicalCellGroupConfig
     //    pdsch-HARQ-ACK-Codebook: dynamic (1)
     harq_ack.pdsch_harq_ack_codebook = srslte_pdsch_harq_ack_codebook_dynamic;

lib/include/srslte/phy/common/phy_common_nr.h

@@ -301,6 +301,25 @@ typedef struct SRSLTE_API {
   uint32_t                   nof_candidates[SRSLTE_SEARCH_SPACE_NOF_AGGREGATION_LEVELS_NR];
 } srslte_search_space_t;
 
+/**
+ * @brief TDD pattern configuration
+ */
+typedef struct SRSLTE_API {
+  uint32_t period_ms;      ///< Period in milliseconds, set to 0 if not present
+  uint32_t nof_dl_slots;   ///< Number of consecutive full DL slots at the beginning of each DL-UL pattern
+  uint32_t nof_dl_symbols; ///< Number of consecutive DL symbols in the beginning of the slot following the last DL slot
+  uint32_t nof_ul_slots;   ///< Number of consecutive full UL slots at the end of each DL-UL pattern
+  uint32_t nof_ul_symbols; ///< Number of consecutive UL symbols in the end of the slot preceding the first full UL slot
+} srslte_tdd_pattern_t;
+
+/**
+ * @brief TDD configuration as described in TS 38.331 v15.10.0 TDD-UL-DL-ConfigCommon
+ */
+typedef struct SRSLTE_API {
+  srslte_tdd_pattern_t pattern1;
+  srslte_tdd_pattern_t pattern2;
+} srslte_tdd_config_nr_t;
+
 /**
  * @brief Get the RNTI type name for NR
  * @param rnti_type RNTI type name
@@ -372,6 +391,24 @@ SRSLTE_API uint32_t srslte_min_symbol_sz_rb(uint32_t nof_prb);
  */
 SRSLTE_API float srslte_symbol_distance_s(uint32_t l0, uint32_t l1, uint32_t numerology);
 
+/**
+ * @brief Decides whether a given slot is configured as Downlink
+ * @param cfg Provides TDD configuration
+ * @param numerology Provides BWP numerology
+ * @param slot_idx Slot index in the frame for the given numerology
+ * @return true if the provided slot index is configured for Downlink
+ */
+SRSLTE_API bool srslte_tdd_nr_is_dl(const srslte_tdd_config_nr_t* cfg, uint32_t numerology, uint32_t slot_idx);
+
+/**
+ * @brief Decides whether a given slot is configured as Uplink
+ * @param cfg Provides TDD configuration
+ * @param numerology Provides BWP numerology
+ * @param slot_idx Slot index in the frame for the given numerology
+ * @return true if the provided slot index is configured for Uplink
+ */
+SRSLTE_API bool srslte_tdd_nr_is_ul(const srslte_tdd_config_nr_t* cfg, uint32_t numerology, uint32_t slot_idx);
+
 #ifdef __cplusplus
 }
 #endif

lib/src/phy/common/phy_common_nr.c

@@ -146,3 +146,49 @@ float srslte_symbol_distance_s(uint32_t l0, uint32_t l1, uint32_t numerology)
   // Return symbol distance in microseconds
   return (N << numerology) * SRSLTE_LTE_TS;
 }
+
+bool srslte_tdd_nr_is_dl(const srslte_tdd_config_nr_t* cfg, uint32_t numerology, uint32_t slot_idx)
+{
+  if (cfg == NULL) {
+    return false;
+  }
+
+  // Calculate slot index within the TDD overall period
+  uint32_t slot_x_ms       = 1U << numerology; // Number of slots per millisecond
+  uint32_t period_sum      = (cfg->pattern1.period_ms + cfg->pattern2.period_ms) * slot_x_ms; // Total perdiod sum
+  uint32_t slot_idx_period = slot_idx % period_sum; // Slot index within the period
+
+  // Select pattern
+  const srslte_tdd_pattern_t* pattern = &cfg->pattern1;
+  if ((slot_idx_period >= cfg->pattern1.period_ms * slot_x_ms)) {
+    pattern = &cfg->pattern2;
+    slot_idx_period -= cfg->pattern1.period_ms * slot_x_ms; // Remove pattern 1 offset
+  }
+
+  return (slot_idx_period < pattern->nof_dl_slots ||
+          (slot_idx_period == pattern->nof_dl_slots && pattern->nof_dl_symbols != 0));
+}
+
+bool srslte_tdd_nr_is_ul(const srslte_tdd_config_nr_t* cfg, uint32_t numerology, uint32_t slot_idx)
+{
+  if (cfg == NULL) {
+    return false;
+  }
+
+  // Calculate slot index within the TDD overall period
+  uint32_t slot_x_ms       = 1U << numerology; // Number of slots per millisecond
+  uint32_t period_sum      = (cfg->pattern1.period_ms + cfg->pattern2.period_ms) * slot_x_ms; // Total perdiod sum
+  uint32_t slot_idx_period = slot_idx % period_sum; // Slot index within the period
+
+  // Select pattern
+  const srslte_tdd_pattern_t* pattern = &cfg->pattern1;
+  if ((slot_idx_period >= cfg->pattern1.period_ms * slot_x_ms)) {
+    pattern = &cfg->pattern2;
+    slot_idx_period -= cfg->pattern1.period_ms * slot_x_ms; // Remove pattern 1 offset
+  }
+
+  // Calculate slot in which UL starts
+  uint32_t start_ul = (pattern->period_ms * slot_x_ms - pattern->nof_ul_slots) - 1;
+
+  return (slot_idx_period > start_ul || (slot_idx_period == start_ul && pattern->nof_ul_symbols != 0));
+}

srsue/src/phy/nr/cc_worker.cc

@@ -181,6 +181,11 @@ void cc_worker::decode_pdcch_ul()
 
 bool cc_worker::work_dl()
 {
+  // Check if it is a DL slot, if not skip
+  if (!srslte_tdd_nr_is_dl(&phy->cfg.tdd, 0, dl_slot_cfg.idx)) {
+    return true;
+  }
+
   // Run FFT
   srslte_ue_dl_nr_estimate_fft(&ue_dl, &dl_slot_cfg);
 
@@ -249,6 +254,11 @@ bool cc_worker::work_dl()
 
 bool cc_worker::work_ul()
 {
+  // Check if it is a DL slot, if not skip
+  if (!srslte_tdd_nr_is_ul(&phy->cfg.tdd, 0, ul_slot_cfg.idx)) {
+    return true;
+  }
+
   srslte_uci_data_nr_t uci_data = {};
   uint32_t             pid      = 0;