A Review on Discontinuous Reception Mechanism as a Power Saving Approach for 5G User Equipments at Millimetre-Wave Frequencies

Improving energy efficiency and extending the lifetime of User Equipment (UE) batteries are among the key performance requirements for the Fifth-Generation (5G) network goals. To realize these goals, ongoing studies are developing schemes to improve both performance requirements. One of the mechanisms at the forefront of these studies is Discontinuous Reception (DRX). This mechanism, which was inherited from the Fourth-Generation (4G) wireless network is crucial, as its performance with regard to the performance requirements for 5G goals has a great impact on the user's satisfaction. Although the DRX mechanism is adapted to meet the power-saving need of a 5G wireless network, the energy expenses for operations at millimetre-wave frequencies are still of concern. In this paper, recent research solutions that consider the application of the DRX mechanism in association with key enabling features and factors such as paging, RRC_INACTIVE, mmWave, and UE mobility are discussed for 5G use cases. In addition, the effect of these features and factors is considered, as well as recent solutions to address the challenges identified. Simulation results of this approach showed an average of 399mW of power consumed in a 24-hour period, which represents a 6% mean percentage reduction in UE power consumption when compared to the existing scheme.