This paper proposes a scheme to select an appropriate gateway based on multiple metrics such as remaining energy, mobility or speed, and number of hops in Mobile Ad Hoc Network (MANET) and the infrastructure network integration. The Multiple Criteria Decision Making (MCDM) method called Simple Additive Weighting (SAW) is used to rank and to select the gateway node. SAW method calculates the weights of gateway node candidates by considering these three metrics. The node with the highest weight will be selected as the gateway. Simulation results show that our scheme can reduce the average energy consumption of MANET nodes, and improve throughput performance, gateway lifetime, Packet Delivery Ratio (PDR) of the MANET and the infrastructure network.

Recently several weighted clustering algorithms have been proposed, however, to the best of our knowledge; there is none that propagates weights to other nodes without weight message for leader election, normalizes node parameters and considers neighboring node parameters to calculate node weights. In this paper, we propose an Energy Efficient and Stable Weight Based Clustering (EE-SWBC) algorithm that elects cluster heads without sending any additional weight message. It propagates node parameters to its neighbors through neighbor discovery message (HELLO Message) and stores these parameters in neighborhood list. Each node normalizes parameters and efficiently calculates its own weight and the weights of neighboring nodes from that neighborhood table using Grey Decision Method (GDM). GDM finds the ideal solution (best node parameters in neighborhood list) and calculates node weights in comparison to the ideal solution. The node(s) with maximum weight (parameters closer to the ideal solution) are elected as cluster heads. In result, EE-SWBC fairly selects potential nodes with parameters closer to ideal solution with less overhead. Different performance metrics of EE-SWBC and Distributed Weighted Clustering Algorithm (DWCA) are compared through simulations. The simulation results show that EE-SWBC maintains fewer average numbers of stable clusters with minimum overhead, less energy consumption and fewer changes in cluster structure within network compared to DWCA.