Performance of IEEE 802.11’s Timing Advertisement Against SyncTSF for Wireless Clock Synchronization

摘要

The lack of provisioning of synchronized timing support from known timing standards in IEEE 802.11 wireless networks has been overcome in IEEE 802.11-2012 through the timing advertisement (TA) mechanism. The scheme, however, presents a synchronization architecture of a cascade of four clocks. It provides no information on how the external time will be synchronized with the built-in clock of the access point (AP) and when the timestamping is performed on the wireless link, which can lead to a loss in synchronization accuracy. To this end, this work analyzes the quantitative performance of the TA mechanism with a non-IEEE802.11 mechanism, SyncTSF, which also uses the same four clocks as in the TA mechanism and compares their performance with the help of simulations. Both schemes offer similar accuracy and precision if the offset corrections involved in both schemes are carried out properly. Nevertheless, SyncTSF is more flexible, as it can be easily implemented using commercial off-the-shelf hardware using only software support. For the implementation of TA mechanism, additional guidelines from the IEEE 802.11 Standard along with dedicated hardware support is required.