diff --git a/arch/sim/src/sim/up_hcisocket.c b/arch/sim/src/sim/up_hcisocket.c
index ff9da37343a..42125bd2b4a 100644
--- a/arch/sim/src/sim/up_hcisocket.c
+++ b/arch/sim/src/sim/up_hcisocket.c
@@ -179,7 +179,7 @@ int bthcisock_register(int dev_id)
  *
  ****************************************************************************/
 
-int bthcisock_loop()
+int bthcisock_loop(void)
 {
   uint8_t type;
   int len;
diff --git a/arch/sim/src/sim/up_hcisocket_host.c b/arch/sim/src/sim/up_hcisocket_host.c
index d785c4240a3..33fc1140ada 100644
--- a/arch/sim/src/sim/up_hcisocket_host.c
+++ b/arch/sim/src/sim/up_hcisocket_host.c
@@ -62,6 +62,43 @@ struct sockaddr_hci
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: bthcisock_host_avail
+ *
+ * Description:
+ *   Monitor the host user channel to see if I/O is possible on socket.
+ *
+ * Input Parameters:
+ *   fd: Host Bluetooth socket fd
+ *
+ * Returned Value:
+ *   TRUE is returned on I/O available
+ *
+ ****************************************************************************/
+
+int bthcisock_host_avail(int fd)
+{
+  struct timeval tv;
+  fd_set fdset;
+
+  /* We can't do anything if we failed to open the user channel */
+
+  if (fd < 0)
+    {
+      return 0;
+    }
+
+  /* Wait for data on the user channel (or a timeout) */
+
+  tv.tv_sec  = 0;
+  tv.tv_usec = 0;
+
+  FD_ZERO(&fdset);
+  FD_SET(fd, &fdset);
+
+  return select(fd + 1, &fdset, NULL, NULL, &tv) > 0;
+}
+
 /****************************************************************************
  * Name: bthcisock_host_send
  *
@@ -190,3 +227,23 @@ int bthcisock_host_open(int dev_idx)
 
   return fd;
 }
+
+/****************************************************************************
+ * Name: bthcisock_host_close
+ *
+ * Description:
+ *   Close a User Channel HCI socket on the Host for the given device idx.
+ *
+ * Input Parameters:
+ *   fd: The resources associated with the open user channel are freed.
+ *
+ * Returned Value:
+ *   Zero is returned on success; a negated errno value is returned on any
+ *   failure.
+ *
+ ****************************************************************************/
+
+int bthcisock_host_close(int fd)
+{
+  return close(fd);
+}
diff --git a/arch/sim/src/sim/up_hcisocket_host.h b/arch/sim/src/sim/up_hcisocket_host.h
index 5ba3a13a9e2..411902a8c0e 100644
--- a/arch/sim/src/sim/up_hcisocket_host.h
+++ b/arch/sim/src/sim/up_hcisocket_host.h
@@ -32,8 +32,10 @@
  * Public Function Prototypes
  ****************************************************************************/
 
+int bthcisock_host_open(int dev_idx);
 int bthcisock_host_send(int fd, uint8_t pkt_type, uint8_t *data, size_t len);
 int bthcisock_host_read(int fd, uint8_t *type, void *buf, size_t len);
-int bthcisock_host_open(int dev_idx);
+int bthcisock_host_avail(int fd);
+int bthcisock_host_close(int fd);
 
 #endif /* _ARCH_SIM_SRC_SIM_HCISOCKET_HOST_H_ */