Impact of hard-and software timestamping on clock synchronization performance over IEEE 802.11

The possibility of equipping devices on the factory floor with wireless communication has brought up new applications and challenges. Among one of these challenges is clock synchronization which is required for easy network management and monitoring. The IEEE 802.11v amendment to IEEE 802.11 has opened the doors for establishing clock synchronization in industrial applications by providing mechanisms and guidelines for synchronization. This work addresses the synchronization means provided by the IEEE 802.11 standard, including the ones mentioned by IEEE 802.11v, and analyses the impact of both software and hardware timestamps on the synchronization performance through test-bed implementations. The results indicate that there are several elements which can affect the quality of both software and hardware time-stamps, which in turn affect the synchronization performance. Moreover, it is also shown that the timestamping accuracy itself is only one factor, and other factors such as control loop settings and synchronization interval also affect the final synchronization performance over WLAN.