e fraction of unoccupied time slots (for the network) or sleep- ing time (for the device) in a period of time corresponding to the cycle of the control signal- ing (for the network) or the periods of DRX (for the device) when no user data transfer takes place. Furthermore, the sleep duration, that is, the continuous periods of time with no trans- mission (for network and device) and reception (for the device), should be sufficiently long. Network energy efficiency (both quantitative and qualitative aspects) is considered as a basic principle in the NR system design. This is the capability to minimize energy consump- tion for radio access while providing the highest possible area traffic capacity. The target is to design the system with the ability to efficiently deliver data, and the ability to provide sufficiently granular transmission cycles, SO that transmission can be discontinued when there are no data to transmit. It further includes the ability to provide the operator with suf- ficient flexibility to adapt sleep cycles of base stations depending on the load, services, and coverage area. In order to quantitatively express and compare this KPI, the following net- work energy efficiency metric in bits per Joule is defined. This definition would allow quantitative comparison of different solutions or energy-saving mechanisms on the basis of efficiency merits, when their impact is not obvious from qualitative analysis. In order to evaluate the overall improvements achieved in 3GPP NR system, the network energy effi- ciency metric is defined as follows: EEscenario = load level EC In the above equation bk refers to the weights of each deployment scenario where the net- work energy efficiency is evaluated. Furthermore, V1, EC1, a denote the traffic per second served by a base station (in bits/s); the power consumed by a base station to serve V1 in Watt = Joule/s, and the weight for each traffic load level, respectively. In other words per second served by a base station) EEscenariok Bits/Joules consumed by a base 