Cooperative multi PTP slaves for timing improvement in an fGn environment

Papers dealing with the Ethernet network have shown that the packet delay variation (PDV) is a long range dependency process which may be modeled as a fractional Gaussian noise. In this letter, a closed-form approximated expression is derived for the offset variance valid for multiple precision time protocol (PTP) slaves (IEEE1588 v2) cooperating together in the network. Using this expression, we obtain, when there is long range dependence in the PDV, the total number of PTP slaves needed to receive the same offset variance as that obtained for the case of white noise PDV.