An Adaptive Discontinuous Reception Mechanism for 5G Unlicensed Band

Discontinuous reception (DRX) mechanism has been successfully adopted in cellular communication systems to improve the energy efficiency of user equipments (UE). UEs periodically wake up to listen to the network for new packets for a short interval. Existing DRX scheme may not achieve satisfactory performance in the 5th generation (5G) new radio unlicensed band mobile system (NR-U), because the listen before talk (LBT) protocol is mandatory for fair spectrum sharing. In this paper, we propose a novel adaptive DRX scheme for 5G NR-U system. If the unlicensed band is occupied by other UEs or other devices, the listening period will be extended accordingly. A semi-Markov chain model is applied to analyze the new scheme mathematically. The theoretical analysis and simulation results demonstrate that the proposed adaptive DRX scheme outperforms the existing algorithms in terms of packets transmission delay and UE power consumption.