Analysis of Downlink and Uplink Decoupling in Dense Cellular Networks

TL;DR

This paper derives tight bounds for the uplink capacity in dense cellular networks with decoupled uplink and downlink, offering practical insights for network densification and performance optimization.

Contribution

It provides the first closed-form bounds for ergodic uplink capacity in decoupled networks with macro and small cells, enabling performance comparison and network planning.

Findings

Decoupling improves uplink capacity compared to coupled scenarios.

Derived bounds are tight and in closed form, facilitating practical network design.

Guidelines for densification levels to meet QoS objectives.

Abstract

Decoupling uplink (UL) and downlink (DL) is a new architectural paradigm where DL and UL are not constrained to be associated to the same base station (BS). Building upon this paradigm, the goal of the present paper is to provide lower, albeit tight bounds for the ergodic UL capacity of a decoupled cellular network. The analysis is performed for a scenario consisting of a macro BS and a set of small cells (SCs) whose positions are selected randomly according to a Poisson point process of a given spatial density. Based on this analysis simple bounds in closed form expressions are defined. The devised bounds are employed to compare the performance of the decoupled case versus a set of benchmark cases, namely the coupled case, and the situations of having either a single macro BS or only SCs. This comparison provides valuable insights regarding the behavior and performance of such networks, providing simpler expressions for the ergodic UL capacity as a function of the distances to the macro BS and the density of SCs. These expressions constitute a simple guide to the minimum degree of densification that guarantees the Quality of Service (QoS) objectives of the network, thus, providing a valuable tool to the network operator of significant practical and commercial value.