From 654fadb1168015197ba7d674bc5dc66acb39c47a Mon Sep 17 00:00:00 2001
From: Thomas Schlichter <thomas.schlichter@iis.fraunhofer.de>
Date: Wed, 10 Sep 2025 14:23:50 +0200
Subject: [PATCH] NR UE: calculate the epoch_hfn whenever an ntn_Config_r17 is
 received

---
 .../open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h |  1 +
 openair1/SCHED_NR_UE/fapi_nr_ue_l1.c                   |  1 +
 openair2/LAYER2/NR_MAC_UE/config_ue.c                  | 10 ++++++++--
 openair2/LAYER2/NR_MAC_UE/mac_defs.h                   |  1 +
 openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c            |  1 +
 5 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h b/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h
index faebaffc6f..c6efc62876 100644
--- a/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h
+++ b/nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h
@@ -562,6 +562,7 @@ typedef struct {
 } fapi_nr_ta_command_pdu;
 
 typedef struct {
+  int epoch_hfn;
   int epoch_sfn;
   int epoch_subframe;
 
diff --git a/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c b/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c
index a3e86ce433..793b5c1f42 100644
--- a/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c
+++ b/openair1/SCHED_NR_UE/fapi_nr_ue_l1.c
@@ -95,6 +95,7 @@ static void configure_ntn_params(PHY_VARS_NR_UE *ue, fapi_nr_dl_ntn_config_comma
     ue->ntn_config_message = CALLOC(1, sizeof(*ue->ntn_config_message));
   }
 
+  ue->ntn_config_message->ntn_config_params.epoch_hfn = ntn_params_message->epoch_hfn;
   ue->ntn_config_message->ntn_config_params.epoch_sfn = ntn_params_message->epoch_sfn;
   ue->ntn_config_message->ntn_config_params.epoch_subframe = ntn_params_message->epoch_subframe;
   ue->ntn_config_message->ntn_config_params.cell_specific_k_offset = ntn_params_message->cell_specific_k_offset;
diff --git a/openair2/LAYER2/NR_MAC_UE/config_ue.c b/openair2/LAYER2/NR_MAC_UE/config_ue.c
index de488fe459..ee6a010cfa 100644
--- a/openair2/LAYER2/NR_MAC_UE/config_ue.c
+++ b/openair2/LAYER2/NR_MAC_UE/config_ue.c
@@ -318,6 +318,10 @@ static void configure_ntn_ta(module_id_t module_id,
   // epochTime_r17 must be present (this is assured by function `eval_epoch_time()`)
   const NR_EpochTime_r17_t *epoch_time_r17 = ntn_Config_r17->epochTime_r17;
   AssertFatal(epoch_time_r17, "epoch_time_r17 should not be NULL here\n");
+  if (epoch_time_r17->sfn_r17 >= frame)
+    ntn_ta->epoch_hfn = hfn;
+  else
+    ntn_ta->epoch_hfn = hfn + 1;
   ntn_ta->epoch_sfn = epoch_time_r17->sfn_r17;
   ntn_ta->epoch_subframe = epoch_time_r17->subFrameNR_r17;
 
@@ -368,9 +372,11 @@ static void configure_ntn_ta(module_id_t module_id,
 
   ntn_ta->ntn_params_changed = true;
 
-  LOG_D(NR_MAC,
-        "SIB19 Rxd. Epoch SFN: %d, Epoch Subframe: %d, k_offset: %ldms, N_Common_Ta: %fms, drift: %fµs/s, variant %fµs/s², "
+  LOG_I(NR_MAC,
+        "SIB19 Rxd. Epoch HFN: %d, Epoch SFN: %d, Epoch Subframe: %d, k_offset: %ldms, "
+        "N_Common_Ta: %fms, drift: %fµs/s, variant %fµs/s², "
         "N_UE_TA: %fms, drift: %fµs/s, variant %fµs/s²\n",
+        ntn_ta->epoch_hfn,
         ntn_ta->epoch_sfn,
         ntn_ta->epoch_subframe,
         ntn_ta->cell_specific_k_offset,
diff --git a/openair2/LAYER2/NR_MAC_UE/mac_defs.h b/openair2/LAYER2/NR_MAC_UE/mac_defs.h
index b43937d362..07721e0369 100644
--- a/openair2/LAYER2/NR_MAC_UE/mac_defs.h
+++ b/openair2/LAYER2/NR_MAC_UE/mac_defs.h
@@ -543,6 +543,7 @@ typedef struct {
 } si_schedInfo_t;
 
 typedef struct ntn_timing_advance_components {
+  int epoch_hfn;
   int epoch_sfn;
   int epoch_subframe;
 
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
index bd9ea09041..7397bdb89f 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
@@ -2849,6 +2849,7 @@ static void schedule_ntn_config_command(fapi_nr_dl_config_request_t *dl_config,
 {
   fapi_nr_dl_ntn_config_command_pdu *ntn_config_command_pdu = &dl_config->dl_config_list[dl_config->number_pdus].ntn_config_command_pdu;
 
+  ntn_config_command_pdu->epoch_hfn = mac->ntn_ta.epoch_hfn;
   ntn_config_command_pdu->epoch_sfn = mac->ntn_ta.epoch_sfn;
   ntn_config_command_pdu->epoch_subframe = mac->ntn_ta.epoch_subframe;
   ntn_config_command_pdu->cell_specific_k_offset = mac->ntn_ta.cell_specific_k_offset;