Spectrum is an operators’ money pit, and its cash cow, and 5G is unlikely to change that any time soon. But in the era of 5G, the focus will change from “how much” spectrum to “what kind”. The path to 5G commercial rollouts is a long and winding one, which will see different phases of 5G come to light, and so different spectrum bands being used.

5G will require both lower and higher spectrum frequencies if it is to deliver on the use cases the industry has projected and proposed. But as operators gear up for 5G, eyes are being cast on the potential of millimeter wave (mmW). While never previously used for telecommunications, its ability to transmit large amounts of data is touted as they key to the 5G treasure chest.

So with 5G just around the corner, could mmW be the next big thing?

Riding the millimeter wave

Just as 5G will differ from 4G, so too will the spectrum frequencies that will be used in the deployment of 5G. It’s therefore crucial that operators acquire the right kind of spectrum if they are to see the birth of the 5G use cases that have long been promised, such as smart transportation, enhanced mobile broadband (eMBB) and the proliferation of the IoT.

The increase in data that will come with 5G will require bands of much higher frequency to transport our content, videos, images and interactions from one place to another. Indeed, as operators ready themselves for 5G, the spectrum battle is beginning. mmW has been poised as the spectrum band for 5G. The band, which lies between 30 gigahertz (GHz) and 300Ghz or often referred to as bands over 24GHz, will allow ultra-high frequency waves and thus, ultra-high speed data to pass through it. By deploying mmW, operators stand to benefit in several ways.

First, the use of mmW will allow operators to increase network capacity and thus the amount of data shared across the network. For a technology whose premise is built on increased bandwidth, the ability to use mmW will significantly enhance operators’ 5G prowess.

Second, this increased network capacity will prove crucial for enhancing and maintaining network QoS and QoE. It’s no use having an ultra-high speed network that suffers from regular downtime as a result of network congestion, and mmW is one way to avoid this, thanks to its ability to transfer bigger volumes of data than other frequency bands (greater throughput means less stalling, and an improved quality of experience).

Third, it is not just smartphone users that will benefit from mmW spectrum; use cases such as autonomous cars and remote health applications will also stand to gain from the reduced latency brought by the additional bandwidth available in mmW spectrum.

No plain sailing

But the use of the mmW spectrum is no easy feat for operators. While mmW brings about several benefits, its capabilities to transmit data over long distances is a significant hindrance. It is anticipated that, despite its ability to transport large amounts of data, mmW can only do so over distances of about 200m or 656 feet. This poses serious challenges if operators are to use this spectrum band to deploy 5G on a wide scale. What’s more, signals over 24GHz are prone to significant path loss and shadowing, whereby transmission waves are easily absorbed by objects in their path, such as trees or buildings, and even humans.

To overcome these challenges and ensure 5G can deliver on its promise, operators will have to deploy additional small cell sites and base stations to cover dense areas where signal propagation is poor, and where coverage is patchy. 3D beamforming will also be required to overcome propagation challenges, whereby smaller base stations will use hundreds of antenna elements to form directional beams for transmission and to receive similar 3D beams from adjacent base stations. But while the addition of antennas to reduce path loss may seem like a good idea, this will not only require a drastic change in current network infrastructure, but operators will also have to contend with device power consumption as 5G devices are forced to support a large number of antennas with very high bandwidth.

Drowning out the challenges

As operators press full steam ahead with the development of 5G, the battle for mmW spectrum is only going to intensify. But despite this band’s promise of higher frequency and greater data transmission, operators will have to overcome several challenges to see 5G become a reality. Operators will struggle to deliver on 5G’s promises if they cannot guarantee that mmW spectrum’s current limitations will come to hinder the end-user experience.

But in this race to 5G, it’s not just about mmW. Operators will also have to think carefully about alternative spectrum usage. Lower frequency cells in the 700MHz band will also prove crucial to enable 5G coverage to wide areas, for example during large events, while higher frequency cells, below mmW bands, will be required to support connecting things and the IoT.

With 5G around the corner, it’s important operators think carefully about what spectrum they have, and what they need. 5G won’t happen without the right spectrum; now it’s up to the telecoms industry to overcome the challenges ahead.

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