Joint Transmit and Receive Energy Minimization Over Multi-Carrier Two-Way Relay Networks

In this work, a three-node, two-way relaying network (TWRN) over a multi-carrier system is considered. The aim is to minimize total energy usage of such a multi-carrier TWRN with the constraint of rate requirements on both sides, with both the transmit energy usage as well as the receive energy usage into account. For comparison, two strategies including digital network coding (DNC) and physical-layer network coding (PNC) are considered. The associated total-energy-minimization problems for both strategies are formulated to be nonconvex optimizations. To achieve global optimality, they are then reformulated to be convex optimization problems and efficiently solved. It is observed in numerical results that, PNC generally outperforms DNC but performs worse in the very low SNR regime, in terms of energy usage. Index Terms Two-way, multi-carrier, multi-access, superposition, energy usage