Wireless sensor networks are emerging technologies that are diverse on energy consumption from different aspects. In the task mode, energy consumption of sensor nodes is categorized in, data packet transmitting, data processing and idle mode. Fundamentally, higher power is required and utilized at the time of data receive as comparing to idle mode. However, power consumption of sensor in idle mode is necessarily important. To conserve energy, the network must provide quality of service sleep schedule and use a mechanism to turn off the radio receiver periodically in coordinating method. Moreover, through dynamically round task management of sensors, significant energy saving can be achieved.