Adaptive Buffer-Aided Wireless Powered Relay Communication With Energy Storage

In this paper, we consider wireless powered relay network, where the energy-constrained decode-and-forward relay is provisioned with both data buffer and energy storage. First, the optimal parameter in time-switching-based relaying scheme is derived to realize the maximal achievable throughput. Second, an adaptive relaying scheme is proposed to dynamically allocate time slots in order to maximize the throughput under the stability constraint of data buffer and the feasibility constraint of energy storage. Third, the relaying scheme is reformulated as a stochastic optimization problem. By employing the Lyapunov optimization framework, an online buffer-energy-aware adaptive transmission scheme is proposed to adjust the transmission according to the dynamic channel state information, the data buffer state information, and the energy state information. Moreover, the tradeoff between the achievable throughput and the transmission delay is presented to show the great potential of the proposed adaptive transmission design to improve the achievable throughput. Finally, simulations are conducted to validate the efficiency of the proposed relaying protocols and confirm the great potentials of buffer-aided relaying in wireless powered relay networks with energy storage.