Resource configuration for minimizing source energy consumption in multi-carrier networks with energy harvesting relay and data-rate guarantee

Simultaneous wireless information and power transfer (SWIPT) is a promising technique for wireless energy harvesting, which enables a relay node to overcome its unwillingness due to the energy awareness, with essentially protecting it from excessively depleting energy reserves. To further improve the energy efficiency, the energy consumption minimization problem aims at minimizing the energy consumption of an active source node, which drives the passive relay node with energy harvesting capability to forward data to the destination. This is studied by jointly considering transmission power limits, time switching factors, and data-rate demand, etc., in a decode-and-forward relay network with SWIPT. The energy consumption minimization problem is formulated as a non-convex optimization problem. The facilitation of the derivation of the optimal solution is through transforming it into an equivalent convex optimization problem by variable substitution. Since the problem is not always feasible, a feasibility assessment problem is then developed by introducing an assessing factor. Simultaneously solving the above inter-related problems, i.e., energy consumption minimization and feasibility assessment, they are unified in a convex-optimization framework, in which both the result about the feasibility assessment and the optimal solution (if it exists) can be obtained. Even if the problem is not feasible, the achievable maximum data rate that network resources can support can be obtained as well. Simulation results further validate that energy consumption minimization-feasibility assessment algorithm is effective in minimizing source energy consumption and in realizing optimal resource configuration.