Energy-efficient MIMO underlay spectrum sharing with rate splitting

This work studies energy efficiency (EE) of multiple-input and multiple-output (MIMO) underlay spectrum sharing, where rate splitting at the secondary transmitter and successive decoding at the secondary receiver is deployed when feasible. EE of the secondary transmission is optimized while satisfying the primary rate requirement and the secondary power constraint. EE is defined as the ratio of the achievable secondary rate and the secondary power consumption, including both the transmit power and the circuit power. Numerical results show that higher EE can be achieved at the cost of achievable rate compared with that of MIMO underlay spectrum sharing with rate optimization, and that rate splitting is beneficial in terms of EE.