  Delay tomography has so far burdened source and receiver measurement nodes in
a network with two requirements such as path establishment and clock
synchronization between them. In this letter, we focus on the clock
synchronization problem in delay tomography and propose a synchronization-free
delay tomography scheme. The proposed scheme selects a path between source and
receiver measurement nodes as a reference path, which results in a loss of
equation in a conventional delay tomography problem. However, by utilizing
compressed sensing, the proposed scheme becomes robust to the loss. Simulation
experiments confirm that the proposed scheme works comparable to a conventional
delay tomography scheme in networks with no clock synchronization between
source and receiver measurement nodes.
