Spectral and energy efficiency of ultra-dense networks under different deployment strategies

TLDR

The 5G push aims to meet a 1000× mobile data demand, with network densification—especially ultra‑dense deployments—identified as a key enabler for higher area capacities. This study evaluates DenseNets across macro, indoor femto, and outdoor DAS deployments, including a novel indoor‑to‑outdoor service paradigm. The authors analyze each deployment’s spectral and energy efficiency under extreme densification, comparing indoor and outdoor scenarios. Results show that densely deployed indoor femtocells outperform outdoor macro densification in spectrum and energy efficiency, while dynamic outdoor DAS provides a capacity‑adaptive, efficient solution for urban areas.

Abstract

To tackle the 1000× mobile data challenge, the research towards the 5th generation of mobile cellular networks is currently ongoing. One clear enabler toward substantially improved network area capacities is the increasing level of network densification at different layers of the overall heterogeneous radio access system. Ultra-dense deployments, or DenseNets, seek to take network densification to a whole new level, where extreme spatial reuse is deployed. This article looks into DenseNets from the perspectives of different deployment strategies, covering the densification of the classical macro layer, extremely dense indoor femto layer, as well as outdoor distributed antenna system (DAS), which can be dynamically configured as a single microcell or multiple independent microcells. Also, the potential of a new indoor-to-outdoor service provisioning paradigm is examined. The different deployment solutions are analyzed from the network area spectral and network energy efficiency perspectives, with extreme densification levels, including both indoor and outdoor use scenarios. The obtained results indicate that dedicated indoor solutions with densely deployed femtocells are much more spectrumand energy-efficient approaches to address the enormous indoor capacity demands compared to densifying the outdoor macro layer, when the systems are pushed to their capacity limits. Furthermore, the dynamic outdoor DAS concept offers an efficient and capacity-adaptive solution to provide outdoor capacity, on demand, in urban areas.