diff --git a/srslte/include/srslte/phch/ra.h b/srslte/include/srslte/phch/ra.h
index c8282ed1b..6b002c9ed 100644
--- a/srslte/include/srslte/phch/ra.h
+++ b/srslte/include/srslte/phch/ra.h
@@ -219,6 +219,8 @@ SRSLTE_API int srslte_ul_dci_to_grant_prb_allocation(srslte_ra_ul_dci_t *dci,
                                                      uint32_t n_rb_ho, 
                                                      uint32_t nof_prb); 
 
+SRSLTE_API int srslte_ra_tbs_idx_from_mcs(uint32_t mcs);
+
 SRSLTE_API int srslte_ra_tbs_from_idx(uint32_t tbs_idx, 
                                       uint32_t n_prb); 
 
diff --git a/srslte/lib/phch/src/ra.c b/srslte/lib/phch/src/ra.c
index b5915a946..573f724e3 100644
--- a/srslte/lib/phch/src/ra.c
+++ b/srslte/lib/phch/src/ra.c
@@ -549,6 +549,15 @@ uint32_t srslte_ra_type2_n_vrb_dl(uint32_t nof_prb, bool ngap_is_1) {
   }
 }
 
+/* Modulation and TBS index table for PDSCH from 3GPP TS 36.213 v10.3.0 table 7.1.7.1-1 */
+int srslte_ra_tbs_idx_from_mcs(uint32_t mcs) {
+  if(mcs < 29) {
+    return mcs_tbs_idx_table[mcs];
+  } else {
+    return SRSLTE_ERROR;
+  }
+}
+
 /* Table 7.1.7.2.1-1: Transport block size table on 36.213 */
 int srslte_ra_tbs_from_idx(uint32_t tbs_idx, uint32_t n_prb) {
   if (tbs_idx < 27 && n_prb > 0 && n_prb <= SRSLTE_MAX_PRB) {
diff --git a/srslte/lib/phch/src/tbs_tables.h b/srslte/lib/phch/src/tbs_tables.h
index 1563fb2e0..636bc67f2 100644
--- a/srslte/lib/phch/src/tbs_tables.h
+++ b/srslte/lib/phch/src/tbs_tables.h
@@ -4,6 +4,11 @@ const int tbs_format1c_table[32] = {
     552, 600, 632, 696, 776, 840, 904, 1000, 1064, 1128, 1224, 1288, 1384, 1480, 1608, 1736
 };
 
+/* Modulation and TBS index table for PDSCH from 3GPP TS 36.213 v10.3.0 table 7.1.7.1-1 */
+const int mcs_tbs_idx_table[29] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
+                                    9, 10, 11, 12, 13, 14, 15, 15, 16, 17,
+                                   18, 19, 20, 21, 22, 23, 24, 25, 26};
+
 
 /* Transport Block Size from 3GPP TS 36.213 v10.3.0 table 7.1.7.2.1-1 */
 const int tbs_table[27][110] = {{      16,   32,   56,   88,  120,  152,  176,  208,  224,  256,  288,