A novel energy saving MIMO mechanism in LTE systems

Long Term Evolution (LTE) supports closed-loop MIMO techniques to improve its performance, but in order to exploit multiuser MIMO channel capabilities, the design of an efficient MAC scheme that supports Multiuser MIMO is still an open issue in the literature. This paper proposes a novel energy efficient MAC scheme for LTE, which aims to achieve simultaneous downlink transmissions to multiple users, through the deployment of a low complexity beamforming technique at the physical layer. Our proposed scheme takes advantage from the multiuser gain of the MIMO channel and the multiplexing gain of the Multibeam Opportunistic Beamforming (MOB) technique, not only to improve the system throughput but also to provide an energy efficient wireless network. We show that our proposed scheme can provide good energy saving performance at the eNB, where the mathematical expression for performance evaluation in terms of the saved energy is also presented.