Introduced configuration of RU IF offset from configuration file

- the RU now supports IF equipment with custom FR1 TX/RX frequencies
- this configuration parameter together with the if_freq parameter allows
  to set a custom IF RX frequency for the gNB
- if the IF offset is not specified, legacy code applies

executables/nr-ru.c

@@ -1149,8 +1149,11 @@ void fill_rf_config(RU_t *ru, char *rf_config_file) {
     if (ru->if_frequency == 0) {
       cfg->tx_freq[i] = (double)fp->dl_CarrierFreq;
       cfg->rx_freq[i] = (double)fp->ul_CarrierFreq;
-    }
-    else {
+    } else if (ru->if_freq_offset){
+      cfg->tx_freq[i] = (double)(ru->if_frequency);
+      cfg->rx_freq[i] = (double)(ru->if_frequency + ru->if_freq_offset);
+      LOG_I(PHY, "Setting IF TX frequency to %lu Hz with IF RX frequency offset %d Hz\n", ru->if_frequency, ru->if_freq_offset);
+    } else {
       cfg->tx_freq[i] = (double)ru->if_frequency;
       cfg->rx_freq[i] = (double)(ru->if_frequency+fp->ul_CarrierFreq-fp->dl_CarrierFreq);
     }
@@ -2494,6 +2497,7 @@ void RCconfig_RU(void)
       RC.ru[j]->att_tx                            = *(RUParamList.paramarray[j][RU_ATT_TX_IDX].uptr);
       RC.ru[j]->att_rx                            = *(RUParamList.paramarray[j][RU_ATT_RX_IDX].uptr);
       RC.ru[j]->if_frequency                      = *(RUParamList.paramarray[j][RU_IF_FREQUENCY].u64ptr);
+      RC.ru[j]->if_freq_offset                    = *(RUParamList.paramarray[j][RU_IF_FREQ_OFFSET].iptr);
 
       if (config_isparamset(RUParamList.paramarray[j], RU_BF_WEIGHTS_LIST_IDX)) {
         RC.ru[j]->nb_bfw = RUParamList.paramarray[j][RU_BF_WEIGHTS_LIST_IDX].numelt;

openair1/PHY/defs_RU.h

@@ -624,6 +624,8 @@ typedef struct RU_t_s {
   int wakeup_L1_sleep_cnt_max;
   /// DL IF frequency in Hz
   uint64_t if_frequency;
+  /// UL IF frequency offset to DL IF frequency in Hz
+  int if_freq_offset;
 } RU_t;
 
 

openair2/ENB_APP/enb_paramdef.h

@@ -96,6 +96,7 @@ typedef enum {
 #define CONFIG_STRING_RU_OTA_SYNC_ENABLE          "ota_sync_enabled"
 #define CONFIG_STRING_RU_BF_WEIGHTS_LIST          "bf_weights"
 #define CONFIG_STRING_RU_IF_FREQUENCY             "if_freq"
+#define CONFIG_STRING_RU_IF_FREQ_OFFSET           "if_offset"
 
 #define RU_LOCAL_IF_NAME_IDX          0
 #define RU_LOCAL_ADDRESS_IDX          1
@@ -124,6 +125,7 @@ typedef enum {
 #define RU_OTA_SYNC_ENABLE_IDX        24
 #define RU_BF_WEIGHTS_LIST_IDX        25
 #define RU_IF_FREQUENCY               26
+#define RU_IF_FREQ_OFFSET             27
 
 /*-----------------------------------------------------------------------------------------------------------------------------------------*/
 /*                                            RU configuration parameters                                                                  */
@@ -157,6 +159,7 @@ typedef enum {
     {CONFIG_STRING_RU_OTA_SYNC_ENABLE,             NULL,       0,       strptr:NULL,     defstrval:"no",          TYPE_STRING,      0}, \
     {CONFIG_STRING_RU_BF_WEIGHTS_LIST,             NULL,       0,       iptr:NULL,       defintarrayval:DEFBFW,   TYPE_INTARRAY,    0}, \
     {CONFIG_STRING_RU_IF_FREQUENCY,                NULL,       0,       u64ptr:NULL,     defuintval:0,            TYPE_UINT64,      0}, \
+    {CONFIG_STRING_RU_IF_FREQ_OFFSET,              NULL,       0,       iptr:NULL,     defintval:0,             TYPE_INT,         0}, \
   }
 
 /*---------------------------------------------------------------------------------------------------------------------------------------*/