HetNets Under Decoupled Uplink and Downlink Access with UE Random Discontinuous Transmission: Local Delay and Energy Efficiency

Due to the limited uplink capability in heterogeneous networks (HetNets), the decoupled uplink and downlink access (DUDA) mode has recently been proposed to improve the uplink performance. In this paper, the random discontinuous transmission (DTX) at user equipment (UE) is adopted to reduce the interference correlation across different time slots. By utilizing stochastic geometry, we analytically derive the mean local delay and energy efficiency (EE) of an uplink HetNet with UE random DTX scheme under the DUDA mode. These expressions are further approximated as closed forms under reasonable assumptions. Our results reveal that under the DUDA mode, there is an optimal EE with respect to mute probability under the finite local delay constraint. In addition, with the same finite mean local delay as under the coupled uplink and downlink access (CUDA) mode, the HetNets under the DUDA mode can achieve a higher EE with a lower mute probability.