Simultaneous Wireless Information and Power Transfer in Two-hop OFDM Decode-and-Forward Relay Networks

Abstract

This paper investigates the simultaneous wireless information and power transfer (SWIPT) for two-hop orthogonal frequency division multiplexing (OFDM) decode-and-forward (DF) relay network, where a relay harvests energy from radio frequency signals transmitted by a source and then uses the harvested energy to assist information transmission from the source to its destination. The power splitting receiver is considered at the relay. To explore the performance limit of such a SWIPT-enabled system, a resource allocation (RA) optimization problem is formulated to maximize the achievable information rate of the system, where the power allocation, the subcarrier pairing and the power splitting factor are jointly optimized. As the problem is non-convex and there is no known solution method, we first decompose it into two separate subproblems and then design an efficient RA algorithm. Simulation results demonstrate that our proposed algorithm can achieve the maximum achievable rate of the system and also show that to achieve a better system performance, the relay node should be deployed near the source in the SWIPT-enabled two-hop OFDM DF relay system, which is very different from that in conventional non-SWIPT system where the relay should be deployed at the midpoint of the line between the source and the destination.

Wireless Energy Harvesting with Cooperative Relaying under the Best Relay Selection Scheme

“…Previous works in this field focused on the degradation of SE due to WEH. For example, in [48], researchers proposed SWIPT for orthogonal frequency division multiplexing (OFDM), and degradation in SE reached approximately 40%. Figure 8 represents the effect of the power-splitting ratio on the EE for PS protocol, The EE decreases as ρ increases from 0.1 to 0.9, for example, when ρ = 0.1 means that 0.9 of the transmitted power from the relay will reach to the destination, which improve the EE, while in case of ρ = 0.9 means that 0.1 of the transmitted power from the relay will reach to the destination, so the EE decreases.…”