diff --git a/executables/nr-gnb.c b/executables/nr-gnb.c
index 8752e9b8c7..84aa00210d 100644
--- a/executables/nr-gnb.c
+++ b/executables/nr-gnb.c
@@ -147,6 +147,7 @@ extern void add_subframe(uint16_t *frameP, uint16_t *subframeP, int offset);
 
 static inline int rxtx(PHY_VARS_gNB *gNB, int frame_rx, int slot_rx, int frame_tx, int slot_tx, char *thread_name) {
 
+  sl_ahead = sf_ahead*gNB->frame_parms.slots_per_subframe;
   nfapi_nr_config_request_scf_t *cfg = &gNB->gNB_config;
 
   start_meas(&softmodem_stats_rxtx_sf);
diff --git a/openair1/SIMULATION/NR_PHY/dlsim.c b/openair1/SIMULATION/NR_PHY/dlsim.c
index ba84abb3c2..54b8d6afee 100644
--- a/openair1/SIMULATION/NR_PHY/dlsim.c
+++ b/openair1/SIMULATION/NR_PHY/dlsim.c
@@ -77,6 +77,7 @@ int32_t uplink_frequency_offset[MAX_NUM_CCs][4];
 double cpuf;
 
 int sf_ahead=4, phy_test = 0;
+int sl_ahead=0;
 uint8_t nfapi_mode = 0;
 uint16_t NB_UE_INST = 1;