Cell DTX Research Articles

Cross-layer framework for capacity analysis in multiuser ultra-dense networks with cell DTx

Cell discontinuous transmission (Cell DTx) is a key technology to mitigate inter-cell interference (ICI) in ultra-dense networks (UDNs). The aim of this work is to understand the impact of Cell DTx on physical-layer sum rates of SBSs and link-layer quality-of-service (QoS) performance in multiuser UDNs. In this work, we develop a cross-layer framework for capacity analysis in multiuser UDNs with Cell DTx. In particular, we first extend the traditional one-dimensional effective capacity model to a new multidimensional effective capacity model to derive the sum rate and the effective capacity. Moreover, we propose a new iterative bisection search algorithm that is capable of approximating QoS performance. The convergence of this new algorithm to a unique QoS exponent vector is later proved. Finally, we apply this framework to the round-robin and the max-C/I scheduling policies. Simulation results show that our framework is accurate in approximating 1) queue length distribution, 2) delay distribution and 3) sum rates under the above two scheduling policies, and further show that with the Cell DTx, systems have approximately 30% higher sum rate and 35% smaller average delay than those in full-buffer scenarios.

Interference Coordination for 5G New Radio

The arrival of the 5G NR provides a unique opportunity for introducing new inter-cell interference coordination (ICIC) mechanisms. The objective is twofold: to better exploit the benefits of ICIC in coherence with the rest of radio resource management (RRM) principles in 5G, and to support new services and deployment scenarios. We propose several enhanced techniques. In the uplink, inter-cell coordination of the pilot sequence configuration mitigates the inter-cell interference problem of such pilots, which is especially severe for cell-edge users. In the downlink, coordinated small cell DTX aims at network interference control and energy consumption reduction, whereas intercell rank coordination can unleash the potential of advanced receivers with minimal control overhead. Besides, on-demand power boosting and coordinated muting can be tailored to meet URLLC requirements. The simulation results quantify the performance benefits of the different techniques under heterogeneous key performance indicators (KPIs). We also discuss the standardization effort required for having each of these techniques included in the 5G NR specifications.

Energy Efficient Network Deployment With Cell DTX

Cell discontinuous transmission (DTX) is a new feature that enables sleep mode operations at base station (BS) side during the transmission time intervals when there is no traffic. In this letter, we analyze the maximum achievable energy saving of the cell DTX. We incorporate the cell DTX with a clean-slate network deployment and obtain optimal BS density for lowest energy consumption satisfying a certain quality of service requirement considering daily traffic variation. The numerical result indicates that the fast traffic adaptation capability of cell DTX favors dense network deployment with lightly loaded cells, which brings about considerable improvement in energy saving.