diff --git a/openair1/PHY/TOOLS/tools_defs.h b/openair1/PHY/TOOLS/tools_defs.h
index 2d8a032570..55668cd44d 100644
--- a/openair1/PHY/TOOLS/tools_defs.h
+++ b/openair1/PHY/TOOLS/tools_defs.h
@@ -139,6 +139,13 @@ extern "C" {
     };
   }
 
+  __attribute__((always_inline)) inline cd_t cdMul(const cd_t a, const cd_t b)
+  {
+    return (cd_t) {
+        .r = a.r * b.r - a.i * b.i,
+        .i = a.r * b.i + a.i * b.r
+    };
+  }
 
   // On N complex numbers
   //   y.r += (x * alpha.r) >> 14