Extending the lifetime of the wireless sensor networks has always been a crucial challenge for the researchers. Most of the energy is consumed in data transmission to the sink. In the recent past some researchers have suggested mobile sink method to minimize energy consumption in wireless sensor networks. The movement of sink is governed by fuzzy logic based mechanism. In this work base station is allowed to move only on a predefined circular path making it practically more feasible. Simulation results are compared with the method having stationary base station. Simulation results show that our scheme reduces energy consumption and thereby enhances lifetime of wireless sensor network by a significant amount as compared to stationary base station case.