diff --git a/openair1/PHY/defs_UE.h b/openair1/PHY/defs_UE.h
index a634a0d585..4f9bc076ff 100644
--- a/openair1/PHY/defs_UE.h
+++ b/openair1/PHY/defs_UE.h
@@ -168,6 +168,19 @@ typedef struct {
   struct sched_param sched_param_ue;
   /// pthread descriptor main UE thread
   pthread_t pthread_ue;
+  /// \brief Instance count for synch thread.
+  /// \internal This variable is protected by \ref mutex_synch.
+  int instance_cnt_synch;
+  /// pthread attributes for synch processing thread
+  pthread_attr_t attr_synch;
+  /// scheduling parameters for synch thread
+  struct sched_param sched_param_synch;
+  /// pthread descriptor synch thread
+  pthread_t pthread_synch;
+  /// condition variable for UE synch thread;
+  pthread_cond_t cond_synch;
+  /// mutex for UE synch thread
+  pthread_mutex_t mutex_synch;
   /// instance count for eNBs
   int instance_cnt_eNBs;
   /// set of scheduling variables RXn-TXnp4 threads