diff --git a/libowlps/owlps.h b/libowlps/owlps.h
index b8b6d5b..623f995 100644
--- a/libowlps/owlps.h
+++ b/libowlps/owlps.h
@@ -114,14 +114,17 @@ typedef struct _owl_timestamp owl_timestamp ;
 struct _owl_captured_request
 {
   uint8_t type ; ///< Type of the captured request
+  // 1 byte alignment
   uint16_t nb_packets ; ///< Number of packets for this request
   uint16_t packet_id ; ///< Number of the current packet
   uint8_t cp_mac_addr_bytes[ETHER_ADDR_LEN] ; ///< MAC of the listener
   uint8_t mobile_mac_addr_bytes[ETHER_ADDR_LEN] ; ///< MAC of the mobile
   uint8_t mobile_ip_addr_bytes[4] ; ///< IP of the mobile
+  // 2 bytes alignment
   owl_timestamp request_time ; ///< Timestamp on the mobile
   owl_timestamp capture_time ; ///< Timestamp of arrival on the listener
   int8_t ss_dbm ; ///< Signal strength measured by the listener (dBm)
+  // 3 bytes alignment
   /* Calibration data */
   float x_position ; ///< X coordinate
   float y_position ; ///< Y coordinate