Power splitting based SWIPT in network-coded two-way networks with data rate fairness: an information-theoretic perspective

This paper investigates the simultaneous wireless information and power transfer (SWIPT) for network-coded two-way relay network from an information-theoretic perspective, where two sources exchange information via an SWIPT-aware energy harvesting (EH)relay. We present a power splitting (PS)-based two-way relaying (PS-TWR) protocol by employing the PS receiver architecture. To explore the system sum rate limit with data rate fairness, an optimization problem under total power constraint is formulated. Then, some explicit solutions are derived for the problem. Numerical results show that due to the path loss effect on energy transfer, with the same total available power, PS-TWR losses some system performance compared with traditional non-EH two-way relaying, where at relatively low and relatively high signal-to-noise ratio (SNR), the performance loss is relatively small. Another observations is that, in relatively high SNR regime, PS-TWR out-performs time switching-based two-way re-laying (TS-TWR) while in relatively low SNR regime TS-TWR outperforms PS-TWR. It is also shown that with individual available power at the two sources, PS-TWR outperforms TS-TWR in both relatively low and high SNR regimes.