Scaling Laws for Infrastructure Single and Multihop Wireless Networks in Wideband Regimes

TL;DR

This paper derives scaling laws for the achievable data rates in large broadband millimeter wave cellular networks, revealing critical bandwidth thresholds where the network shifts from being limited by degrees of freedom to power constraints, and highlighting the advantages of multi-hop architectures.

Contribution

It provides the first analysis of how bandwidth and network size impact feasible rates in wideband millimeter wave networks, identifying critical thresholds and the benefits of multi-hop over single-hop architectures.

Findings

Critical bandwidth thresholds exist where rate scaling saturates.

Multi-hop architectures outperform single-hop when user density grows.

Networks become power-limited beyond certain bandwidths.

Abstract

With millimeter wave bands emerging as a strong candidate for 5G cellular networks, next-generation systems may be in a unique position where spectrum is plentiful. To assess the potential value of this spectrum, this paper derives scaling laws on the per mobile downlink feasible rate with large bandwidth and number of nodes, for both Infrastructure Single Hop (ISH) and Infrastructure Multi-Hop (IMH) architectures. It is shown that, for both cases, there exist \emph{critical bandwidth scalings} above which increasing the bandwidth no longer increases the feasible rate per node. These critical thresholds coincide exactly with the bandwidths where, for each architecture, the network transitions from being degrees-of-freedom-limited to power-limited. For ISH, this critical bandwidth threshold is lower than IMH when the number of users per base station grows with network size. This result suggests that multi-hop transmissions may be necessary to fully exploit large bandwidth degrees of freedom in deployments with growing number of users per cell.