diff --git a/src/UpperPHY/LDPC/arm_ldpc_rate_matching.cpp b/src/UpperPHY/LDPC/arm_ldpc_rate_matching.cpp
index 8efac64..c9cb8c4 100644
--- a/src/UpperPHY/LDPC/arm_ldpc_rate_matching.cpp
+++ b/src/UpperPHY/LDPC/arm_ldpc_rate_matching.cpp
@@ -59,6 +59,17 @@ void bit_selection(uint32_t z, uint32_t n, uint32_t e, uint32_t len_filler_bits,
     }
 
     in_bits = scratch_buf1;
+
+    // k0 is an index within the encoder output with filler bits
+    // but in_bits is now without filler bits
+    // so there is an offset to take into account depending on
+    // whether k0 falls before, within or after the filler bits
+    if(k0 > len_s_f_bits) {
+      k0 = k0 - len_filler_bits;
+    } else if(k0 > len_s_bits && k0 <= len_s_f_bits) {
+      k0 = len_s_bits;
+    }
+
   }
 
   // k0 depends on the redundancy version id.