Wireless Sensor Network (WSN) is a wireless network consisting of spatially distributed sensor nodes using to monitor physical or environmental conditions. In many application scenarios, the data collecting element (mobile sink) cannot move freely in the deployed area. In such approaches the mobile sink moves to predetermined sojourn points and query each sensor node individually. A sensor node can conveniently identify its hop count distances to these landmarks. This approach is much more flexible in terms of sinks' movement, but incurs significant control message overheads.