Optimal Offline Packet Scheduling in Energy Harvesting 2-user Multiple Access Channel with Common Data

Energy harvesting with the optimum power consumption and packet scheduling increase the lifetime and sustainability of the wireless sensor networks (WSNs) leading to green communications. Optimal packet scheduling solutions available for 2-user multiple-access channel (MAC) systems with energy harvesting transmitters do not consider the common data observed when collected sensor data is spatially or temporally correlated. Furthermore, the total received energy depends on the amount spent on the common data. In this paper, optimal packet scheduling for energy harvesting Gaussian MAC with common data is achieved by assuming the deterministic knowledge of the data and energy packets, i.e., offline solution, while also modelling the effect of the total received energy constraint. Optimum solution is achieved practically with a complex 3-level water filling algorithm. The algorithm is compared with the gradient descent search algorithm giving the global optimum solution. Furthermore, the capacity boundary region is numerically simulated by using water filling algorithm and the optimization results are compared for various points on the capacity boundary surface.