  Energy Harvesting (EH) is a novel technique to prolong the lifetime of the
wireless networks such as wireless sensor networks or Ad-Hoc networks, by
providing an unlimited source of energy for their nodes. In this sense, it has
emerged as a promising technique for Green Communications, recently. On the
other hand, cooperative communication with the help of relay nodes improves the
performance of wireless communication networks by increasing the system
throughput or the reliability as well as the range and efficient energy
utilization. In order to investigate the cooperation in EH nodes, in this
paper, we consider the problem of optimal power and rate allocation in the
degraded full-duplex Gaussian relay channel in which source and relay can
harvest energy from their environments. We consider the general stochastic
energy arrivals at the source and the relay with known EH times and amounts at
the transmitters before the start of transmission. This problem has a min-max
optimization form that along with the constraints is not easy to solve. We
propose a method based on a mathematical theorem proposed by Terkelsen [1] to
transform it to a solvable convex optimization form. Also, we consider some
special cases for the harvesting profile of the source and the relay nodes and
find their solutions efficiently.
