  We report preliminary results of a simulation study on the multi-hop
extension of the recently-proposed energy-efficient wireless sensor network
time synchronization scheme based on time-translating gateways. Unlike the
single-hop case, in multi-hop time synchronization a sensor node sends
measurement data to a head node through gateways which translate the timestamp
values of the received measurement data. Through simulations for two-hop time
synchronization, we analyze the impact of the addition of a gateway and its
translation of timestamp values on the clock frequency and measurement time
estimation and thereby demonstrate the feasibility of the multi-hop extension
of the energy-efficient WSN time synchronization based on time-translating
gateways.
