Optimal time allocation for RF-powered DF relay-assisted cooperative communication

What is it about?

In this letter, we consider a decode-and-forward (DF) relay-assisted RF-powered cooperative communication between an RF energy harvesting source and an information sink. DF relay aids the communication between these two distant wireless nodes by (i) RF energy transfer to the source, and (ii) relaying source data to the sink. To enable efficient RF-powered delay-constrained information transfer to the sink under Rayleigh fading, joint global-optimal time allocations for information and energy transfer are derived. Impact of relay position on throughput and optimality of the analytical solutions are numerically investigated.

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Why is it important?

We considered DF relay-powered two-hop WIT between an RFH source S and information sink D. To enable efficient RF-powered delay-constrained WIT, we first derived outage probability at D for achieving a desired rate. After that we proved global-optimality of throughput maximization problem and obtained OTA for RFET and WIT. We also derived closed-form expression for tight approximation of OTA to gain analytical insights on the role of different system parameters. The numerical results offered insights about the optimal relay position. Finally, we showed that the proposed OTA offers significant throughput enhancement over uniform allocation, which can help in realization of perpetual operation of RF-powered communication networks.