How Does Spectrum Affect Mobile Network Deployments? Empirical Analysis Using Crowdsourced Big Data

Zoraida Frias,Edward J Oughton,Luis Mendo

doi:10.1109/access.2020.3031963

Zoraida Frias, Edward J Oughton + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.3031963

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Abstract

Despite the growing trend towards the use of big data methodologies, there is still limited application of such techniques to understand how spectrum is used in mobile networks. In this paper we analyse how low (<; 1 GHz) and high (>1 GHz) frequency spectrum is used in 4G networks in urban areas, in relation to eNodeB density, available bandwidth, Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ). We present a method to analyse the strategies used by Mobile Network Operators (MNOs) to deal with traffic congestion, and the degree to which they must densify their networks depending on their spectrum portfolio. Using crowdsourced data from 2017 from a popular mobile app, we apply this method to Greater London. We find that the fraction of sites that fully use all available bands to the MNO range from 2% to 20%. Additionally, MNOs with large bandwidth use 42% fewer sites on average in dense urban environments. This difference decreases in suburban areas to 23% fewer sites. The lowest frequencies in each eNodeB tend to exhibit lower RSRP values, as they are often used to serve cell-edge users. These frequencies also show lower RSRQ values because of higher interference caused by neighbouring cells. Similarly, large (high frequency) bandwidth improves RSRQ as it allows for fewer users per MHz, which reduces interference and enables larger cell sizes. We conclude that in dense urban environments, the available bandwidth, rather than propagation properties, determines the preferred band for network deployment by MNOs.

Highlights

Over the last decade, mobile networks have experienced unprecedented growth rates in traffic demand
The results are structured in two blocks: (i) those obtained from the site density estimation and (ii) those derived from the reported Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ) values
A. eNodeB DENSITY BY FREQUENCY BAND COMBINATION Tables 2 – 5 show the eNB density per geotype by the spectrum frequency combinations used for the four Mobile Network Operators (MNOs)

Summary

Introduction

Mobile networks have experienced unprecedented growth rates in traffic demand. Expanding network capacity has historically been addressed via three network expansion techniques, namely (i) densifying the network by building more cell sites, (ii) increasing the available spectrum for mobile services and/or (iii) using more advanced technologies with higher spectral efficiencies Each of these options can result in large differences in terms of the capacity, coverage and cost of a mobile network, meaning there is a large space of possibilities for different infrastructure deployment strategies. For some of their sites, MNO1 and MNO2, and MNO3 and MNO4 share two networks of passive infrastructure under respective joint ventures These asymmetries in the configuration of spectrum resources provide an interesting case to study how different MNOs have developed deployment strategies to expand network capacity

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