Fundamental limits of energy-efficient resource sharing, power control and discontinuous transmission

The achievable gains via power-optimal scheduling are investigated. Under the QoS constraint of a guaranteed link rate, the overall power consumed by a cellular Base Station (BS) is minimized. Available alternatives for the minimization of transmit power consumption are presented. The transmit power is derived for the two-user downlink situation. The analysis is extended to incorporate a BS power model (which maps transmit power to supply power consumption) and the use of Discontinuous Transmission (DTX) in a BS. Overall potential gains are evaluated by comparison of a conventional State-Of-The-Art (SOTA) BS with one that employs DTX exclusively, a power control scheme and an optimal combined DTX and power control scheme. Fundamental limits of the achievable savings are found to be at 5.5 dB under low load and 2dB under high load when comparing the SOTA consumption with optimal allocation under the chosen power model.