diff --git a/openair1/PHY/NR_TRANSPORT/nr_dlsch.c b/openair1/PHY/NR_TRANSPORT/nr_dlsch.c
index aa75bd6555..efbf345042 100644
--- a/openair1/PHY/NR_TRANSPORT/nr_dlsch.c
+++ b/openair1/PHY/NR_TRANSPORT/nr_dlsch.c
@@ -175,7 +175,7 @@ for (int l=0; l<rel15->nb_layers; l++)
     //to be moved to init phase potentially, for now tx_layers 1-8 are mapped on antenna ports 1000-1007
 
   /// DMRS QPSK modulation
-  uint16_t n_dmrs = (rel15->n_prb*rel15->nb_re_dmrs)<<1;
+  uint16_t n_dmrs = ((rel15->n_prb+rel15->start_prb)*rel15->nb_re_dmrs)<<1;
   int16_t mod_dmrs[n_dmrs<<1];
   uint8_t dmrs_type = config->pdsch_config.dmrs_type.value;
   uint8_t mapping_type = config->pdsch_config.mapping_type.value;