The wireless sensor node can only be equipped with a limited power source. In some application scenarios, replenishment of power resources might be impossible. Sensor node lifetime, therefore, shows a strong dependence on battery lifetime. Hence, power conservation and power management take on additional importance. The main task of a sensor node in a sensor field is to detect events, perform quick local data processing, and then transmit the data. Power consumption can hence be divided into three domains: sensing, communication, and data processing. One of the most commonly used Power management techniques is to allow a node to follow sleep-wake up-sample-compute-communicate cycle. Based on the amount of the battery availability, by adopting the proper information dissemenitation schemes, the network life time can be extended. This process relies on hardware support for implementing sleep states, permits the power consumption of a node to be reduced by many orders of magnitude.