Explaining 5G

By Milan Milanović Oct 24, 2018 | Original Speedtest article here.

5G stands for "Fifth Generation" Wireless Technology and is the next evolution for mobile technology after 4G LTE. 5G promises to bring faster download speeds and lower latency. 5G enables operators to address increasing growth in wireless data transmissions for mobile and internet of things (IoT) devices.

A brief history of cellular technologies

Every decade or so, a new generation of mobile technology has brought performance improvements and has introduced new applications and use cases.

  • 1G, in the 1980s, (analog cellular) enabled mobile phone calls.
  • 2G, in the 1990s brought digital voice and texting. In the 2000s, 3G
  • 3G, in the 2000s brought the mobile internet at basic speeds
  • 4G/LTE in the 2010s brought faster internet and streaming HD video

Now in the 2020s, 5G is the next marketing term to describe the next step in Wireless networks. Defined by the 3rd Generation Partnership Project (3GPP) standards body, 5G is listed as wireless standard "Release 15" and "Release 16." 5G is also sometimes referred to as 5G NR, which stands for 5G New Radio.

What are the promises of 5G?

5G promises increase in speeds and capacity. A significant increase in download and upload speeds could enhance many existing use cases including cloud-based storage, augmented reality and artificial intelligence.

5G will also enable cell sites to communicate with a greater number of devices. Reduced latency could enable edge computing, making possible remote graphic rendering for enhanced gaming. Primarily a mobile technology, 5G will also allow mobile operators to deliver fixed wireless broadband service, which also stands to increase speeds.

Is 5G really that much faster than 4G?

Yes. The initial wave of 5G smartphones expected in 2019 will be able to reach peak speeds of 5 Gbps or so. As networks and chipsets mature, peak speeds of tens (or even hundreds) of gigabits per second will theoretically be achievable and devices capable of 10-20 Gbps are expected in the next 5 years. In comparison, the fastest 4G LTE networks in the world are breaking the 1 Gbps mark and the latest 4G LTE devices are capable of reaching 1.4 Gbps.

Two years ago, T-Mobile and Ericsson demonstrated over 12 Gbps on a 5G connection. The first global 5G end-to-end handset solution has recently been announced by Qualcomm, and will deliver mobile speeds of up to 5 Gbps to end users in 2019. Whether carriers choose to provide service at these speeds remains to be seen.


5G also introduces a host of new technologies that will make networks faster, more energy efficient, more responsive and more reliable including network slicing and beamforming/beamtracking.

Can Speedtest measure 5G?

Ookla, the company behind Speedtest, is ready for 5G. We’ve been optimizing the Speedtest app and preparing our infrastructure to accurately measure and display 5G-level speeds. In fact, we’re already seeing 5G tests as mobile operators use Speedtest to test their infrastructure.

When and where will 5G be available?

5G trials and pre-standard (5GTF) deployments are already underway. Both Verizon and AT&T offer fixed-wireless 5G in several major markets, including Sacramento, Houston, Indianapolis and Los Angeles. But the 5G NR (New Radio) networks based on 3GPP Release 15 standard are expected at the tail end of this year. AT&T promised to have the first mobile 5G "wireless hotspot" device shipping this year. And the first wave of 5G NR smartphones are expected during the first half of 2019.

The initial 5G NR deployments in late 2018 and early 2019 will be "non-standalone" (NSA). This timing means that for the time being:

  1. Operators will continue using their existing 4G LTE network core for voice, handoffs and signaling, and
  2. Operators will bond the existing 4G signal with the 5G air interface using a technique called carrier aggregation

While the continued use of 4G LTE won’t achieve the true capability of 5G, it will ensure seamless transition to standalone (SA) 5G and allow operators to gracefully repurpose legacy spectrum over the next decade. Many operators continue heavily investing into LTE networks, expecting 4G/LTE to serve as the main workhorse coverage layer well into the 2020’s.

Can my phone get 5G?

Once a 5G network is deployed in your area, you will still need a capable smartphone to access it. The 5G-capable chipsets are currently being tested by smartphone manufacturers and network operators. The first commercial 5G smartphones are expected to be available in the first half of 2019. By that time all four operators are expected to launch mobile 5G networks in several markets throughout the U.S.

Network slicing helps 5G prioritize traffic

5G introduces a new technology called "network slicing", which creates multiple logical partitions within resource allocations that are designed to address specific use cases ranging from mission-critical (e.g. self-driving cars) to IoT devices. This is preferable to the 4G scenario where all use cases have to share a single physical layer partition.

For example, IoT devices like smart meters and home appliances (which do not require fast speeds, low latency, or a high level of prioritization) talk to the network once a day or week. This means they can be supported with a small sliver of network resources. On the other hand, mobile operators can chose to prioritize the partition allocated for specific services like autonomous vehicles, remote surgery or remote manufacturing that require very low latency and high quality of service.

Best of all, the user experience on "best effort" consumer devices like smartphones and tablets will not be affected on 5G because these special services will be delivered within their own relatively small slivers of spectrum. This type of resource management has never been possible before, and it leads to much improved spectral utilization and monetization of deployed resources.

How 5G uses spectrum

5G uses Orthogonal Frequency Division Multiplexing (OFDM)-based waveform, a modulation format used for popular wireless technologies like 4G/LTE and Wi-Fi.

For decades, operators have been investing billions of dollars to acquire 10 MHz, 15 MHz or 20 MHz slivers of spectrum to address exponential growth in capacity demand from subscribers. In order to deliver much faster speeds and massive network capacity, mobile operators in the United States are mainly investing in the millimeter Wave (mmWave) spectrum for 5G, specifically in the 28 GHz and 39 GHz bands. The main attractiveness of this high-band spectrum is its immediate availability and quantity as the mmWave frequency range includes hundreds of megahertz of unused spectrum that’s available for immediate 5G deployment.

While the high band frequencies will offer very large amounts of bandwidth, the mmWave frequencies will be limited by their short range. They are also not well-suited for deployments on large cell towers due to necessary quality measures. This short range will force operators to densify their networks using 5G small cells positioned closer to users.


Advanced techniques for quality signal on high-frequency bands

High-spectrum airwaves are finicky and bring challenges, including significantly reduced propagation characteristics, increased path loss and scattering. To tackle these issues, the use of advanced techniques like beamforming and beamtracking are necessary.

Beamforming is the network signaling system implemented on network basestations that identifies the most efficient signal delivery to a user. Instead of flooding the area with a signal in all directions, beamforming focuses energy into a beam to minimize interference. Beamtracking, a technique implemented on mobile devices, helps with beam selection and signal retention. Beamforming and beamtracking require very powerful algorithms working together to focus the cleanest possible beam of electromagnetic energy to each user and reduce inter-site interference.

While we’re accustomed to seeing huge cell towers using giant antennas required for low and mid frequency bands, 5G mmWave will rely on dense, antenna deployments. Instead of two or four antenna elements, each mmWave small cell will have hundreds of antennas required for beamforming and beamtracking to properly work. This is commonly referred to as massive MIMO (mMIMO). Massive MIMO in 5G will offer better interference measurements and link adaptation via the improved channel state information (CSI) feedback mechanism. This will result in improved data rates and reduced retransmissions.


The upside is that the mmWave antennas are many times smaller than typical cell antennas and can be deployed on light posts, rooftops, city street furniture and other areas typically found in inhabited environments. For this reason, cities will get mmWave 5G first where operators add capacity in high traffic areas.

5G at other frequencies

5G has also been proposed in the sub-6 GHz spectrum range. This frequency won’t offer as much capacity relative to mmWave, but it will deliver better coverage. Sub-6 GHz spectrum will also offer improved spectral efficiency by the way of Higher Order MIMO (4×4 MIMO) when paired with the mid-band spectrum (2.5 GHz, 3.5 GHz initially). In the U.S., Sprint has announced plans for 5G leveraging 2.5GHz spectrum.

T-Mobile’s sub-6GHz 5G deployments, expected in 2019, will include 600 MHz low-band. This should provide a strong coverage layer and serve as a foundation for future mid- and high-frequency band deployments, because the low-band frequency has better propagation characteristics than the mid- and high-band frequencies.

Outside the U.S., most operators are using 3.5 GHz for 5G.

What else can 5G do?

5G isn’t only about attaining the fastest speeds or ultra-low latency. 5G will enable the use of automation in a broad range of industries from autonomous manufacturing, autonomous vehicles, medicine, retail, education, to smart homes and smart cities. It will promote the use of low-cost sensors, which will talk to the network intermittently, use low amounts of data, and draw very little power. This will extend IoT device battery life from several hours to several years.

These sensors can be deployed anywhere, in autonomous vehicles for collision avoidance, autonomous drones providing temporary cell coverage in targeted areas, in the urban core (parking, traffic lights, bridge tolls, air quality, etc.) and in rural environments (help detect predators, alert farmers to changes in chemical composition of the soil, etc.).

From the technological standpoint, the 5G NR is designed to be future-proof and flexible enough to address known and unknown use cases as the way we use it evolves. The new air interface and 5G core network are also still being perfected, and over the next 2-5 years.