Wireless sensor networks (WSN) are an ad hoc network consisting of miniaturized autonomous sensors that communicate with each other over a radio link. In this paper, the authors' contribution is a cross-layer approach. To achieve this approach, the authors proposed in the first part an improvement of LEACH algorithm named WEIGHTED_LEACH. This algorithm is an enhancement of LEACH by inserting novel factors in the threshold equation in order to choose the best node to be CH by competitiveness strategy. In the second part, the authors propose a new adaptable cross-layer design realized by proposed algorithm and AODV protocol with cross layer interaction algorithm. This is an improvement by the control of data fusion in the network using multi-hop routing based on weight metric deducts from relative parameters of node such RSSI, SINR, residual energy, and distance. A comparative analysis between WEIGHTED_LEACH and LEACH, shown for different configurations the efficiency of the proposition in terms of energy saving and life time of WSN cluster, are evaluate under the NS2 simulator.