Wireless communication presents the most attractive sign of development in this decades. It contributes to the appearance of Wireless Sensor Network (WSN) which is invented in order to increase the supervision capacity for such phenomenon. It gets more regard from both the customers and the research society. (WSNs) is composed from numerous wireless sensor nodes which suffer from a very serious energy constraint. For this raison we are interested to the standard of IEEE 802.15.4 with beacon enabled mode. This work suggests a multi mode approach to the technology of IEEE 802.15.4 as a new technique to extend the lifetime of the network. The paper interests to network largely extended with cluster tree topology. In such a way that the network becomes divided to many subgroups. In each subgroup, a PAN coordinator is placed as a coordinator to its children. Besides, every subgroup has its specific parameters of Beacon Order (BO) and Superframe Order (SO) which depend only from the remaining energy in the battery of the nodes. When a node suffers from lack of energy, its PAN coordinator parent intervene by changing its main parameters (BO, SO) in order to postpone its death.