oa Energy saving mechanism in multiantenna LTE systems

Long Term Evolution (LTE) supports closed-loop MIMO techniques to improve its performance; however, in order to exploit the multiuser MIMO channel capabilities, the design of an efficient MAC scheme that supports MU-MIMO is essential and is still an open issue in the literature. This work 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 benefits 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 expressions for performance evaluation in terms of throughput and saved energy are also presented.