New macrocell downlink energy consumption minimization with cell DTx and power control

Power control (PC) and discontinuous transmission (DTx) can reduce the power consumption of a base station (BS). When both are used, there is, for each user, a trade-off between service time and transmit power in order to minimize the energy consumption of the base station. In this paper, we analyse this trade-off and we propose a new efficient algorithm for the computation of the optimal service time and transmit power of all users. We show that in most cases, closed-form expressions can be used. For others, we prove that the search for the optimum can be changed into a root-finding problem which can be solved efficiently with the Newton's method. Numerical results show that, compared to the use of DTx only, the proposed strategy allows to save up to 4% (7W) of the total energy consumption.