Joint Optimization of Base Station Deep-Sleep and DTX Micro-Sleep

When both base station (BS) deep-sleep and discontinuous transmission (DTX) are applied to improve network energy efficiency (EE), switching BS into deep-sleep mode would increase the load of remaining active BSs and thereby reduce their energy savings via DTX. This paper studies the optimal BS operation strategy when both deep-sleep and DTX are employed. Queuing theory and stochastic geometry are jointly applied to model network performance with consideration of both traffic dynamics and channel quality variations. Analytical expressions of average BS load and network EE are derived. Both analytical and simulation results show that there is a trade-off between deep-sleep energy saving and DTX energy saving when the energy saving capacity of DTX is considerable. Analytical expression of the optimal percentage of deep-sleep BSs is provided.