Nowadays the energy consumption has become a critical challenge in Wireless Sensor Network (WSN). Wireless connection suffer from some weaknesse chiefly fault detection and energy efficiency which stay again the main problems in (WSN). Both was under the scope of research communities and industry engineers. We are interested to the IEEE 802.15.4 standard with beacon enabled mode. IEEE802.15.4 is a protocol designed to Physical (PHY) layer and Medium Access Control (MAC) for WSN. We intervene in the Superfame Duration (SD) which present the main private characteristic of the MAC frame in IEEE 802.15.4 in order to minimise the energy consumption when the energy level in a battery reach a critical level. IN-ETMANET/OMNeT++ simulator is used to present our method.