Study on cross-layer optimization in wireless sensor networks under energy constrains

Cross-layer design has been proposed to reduce the energy consumption in wireless sensor networks (WSN). The problem can be modeled as a hybrid non-linear optimization problem for integer constrains involving, which is a challenging task. As the number of nodes increases, the computational complexity grows exponentially. Constrained by computational complexity, previous work by other researchers mainly focused on no more than 4 nodes along a line (1- dimensional), so the advantages of cross-layer optimization cannot be fully explored and demonstrated. By solving the problem with mathematical models and numerical methods, we propose a detailed study on cross-layer optimization with up to 9 nodes in planar case (2-dimensional), which is more realistic. Numerical results show that optimal combination of multihop routing, link adaptation and variable-length TDMA schemes lead to significant energy savings in WSNs.