Test and measurement in a mmWave 5G world

The advancements in 5G represents the next major evolution of mobile communication technology and is enabling a wider diversity of tasks such as the deployment of the ‘Internet of Things’. It does, however, bring with it a number of significant hurdles that must be overcome. For example, frequency spectrum availability is limited and, as a result, 5G must operate at even higher frequencies to deliver the faster data speeds.

This brings into play the mmWave band, which has its own unique challenges such as reliability and ruggedness of cabling. Junkosha is developing a new generation of cables and interconnects that will stand up to these rigours of higher frequencies and will operate efficiently in environments with high flexure and temperature change. Indeed, the key differentiator for Junkosha is phase/amplitude stability over temperature changes, especially in a room temperature of +19˚C (the PTFE Knee).

This article will discuss the current status of 5G, the requirements of mmWave frequencies, and what the future of this industry might look like.

Where is 5G now?

The 5G spectrum encompasses four primary bands: low-band between 600–900MHz, mid-band between 2.5–4.2GHz, mmWave frequencies above 24GHz, and what is known as ‘Unlicensed’ spectrum, which can be accessed for a variety of uses including 5G.

Back in late 2017, the 3rd Generation Partnership Project (3GPP) – the standards body that develops protocols and regulations for mobile telecommunication – released the first specifications for 5G. Since then, the development of 5G technology has evolved at considerable speed.

5G networks have launched around the world and, though many roll-out schedules have been delayed due to the COVID-19 outbreak, these networks continue to expand. Many operate alongside existing 3G and 4G technologies to provide optimum coverage and connection speeds.

In the US, each of the main four carriers (Verizon, T-Mobile, Sprint and AT&T) offer 5G connectivity. Verizon launched its 5G mobile network at the start of April 2019, making it the first carrier in the world to offer the next-generation network.

By the end of 2019, Verizon 5G covered 31 cities across the US. In the UK, EE was the first network to launch 5G in May 2019, closely followed by Vodafone and O2. With the launch of 5G networks has come the regular release of 5G-enabled devices with Samsung, Huawei and Apple all offering a wide portfolio of such devices.

The strategies behind 5G deployment vary significantly, each with its own respective advantages and disadvantages. Some operators utilise ultra-high speed but low-area mmWave technology, whilst others opt for sub-600Mhz frequencies that have greater reach but deliver lower speeds.

There are also those that sit in the mid-band area of 2.5Ghz. Regardless of the underlying strategy, users of any 5G network can expect faster speeds than any previous generation of cellular technology.

What is mmWave technology?

Thanks to the development of 5G, the demand for mmWave frequencies is no longer the preserve of military and space-age applications; instead, it is now being demanded in mainstream technologies. Since the relevant section of the spectrum (24GHz to 100GHz) is relatively unused, mmWave technology aims to greatly increase the amount of bandwidth available over small, densely populated areas where data congestion is high. This short wavelength also enables faster data transfer, though its transfer distance is relatively short. Path loss also presents a key issue for mmWave frequencies; obstacles such as vegetation, walls and glass, as well as the general interference encountered in urban environments, all have a significant impact.

To enable systems to deliver the required outputs at the higher mmWave frequency, ‘phase performance that endures’ is a statement that the cabling and interconnects used must live up to, especially in the test and measurement environment. At these frequencies, interconnects are very small, which means connector design is a complicated task. In addition, the amount of bending and stress the cabling is placed under is significant, resulting in an environment that requires phase stable cables to be installed.

The broad deployment of 5G networks necessitate sophisticated instrument testing and cabling of the highest quality to ensure the faster connections, higher throughput, and greater capacity inherent in the promise of 5G. Interconnects are often considered the weakest link of a system and remain the most critical element in terms of reliability, hence it is crucial that engineers use cabling and interconnects that have been built for the 5G world.

The role of innovative cabling

Over the last 18 months, Junkosha has launched a number of high-end mmWave cabling solutions – including the MWX004, MWX051, MWX061 and MWX071 that reach 130GHz at their highest specification. These new interconnect solutions have all been designed to withstand the most rigorous of testing environments and all feature high performing dielectric material and high flex life thanks to Junkosha’s expanded-PTFE tape wrapping technology.

The most recent innovation, MWX161, is able to reach the 67GHz range and boasts phase stability against bending and temperature fluctuation, alongside mechanical characteristics by using SUS flexible tubing for protection. The small diameter of its connectors make it well suited to enable easy connection to a multi-port Vector Network Analyser (VNA) and for the simple testing of Printed Circuit Board (PCB) signal integrity. It can also be used in narrow pitch RF matrix switchers and multiple connector device under test (DUT) boards which serve as an interface circuit between the automatic test equipment and the DUT.

In a 5G future where both humans and devices will require constant wireless connectivity, the world demands increased network capacity. This calls for both an amplification of, and more efficient use of, the available frequency spectrum through the application of innovative technologies.

Junkosha’s latest interconnects provide VNA manufacturers with the capability to test high frequency networks that are at the heart of tomorrow’s highly sophisticated systems.

What are the applications?

We are looking at a future that includes increased connected devices that demand reduced latency to enable real-time applications. Qualcomm commissioned ABI Research anticipates that 5G represents approximately a 10x decrease in latency compared to previous cellular generations, alongside a much improved data rate.

Indeed, one of the biggest differentiators between 5G and previous cellular connectivity is that it is designed to bring interconnect devices, machines and people closer than ever before, also referred to as the Internet of Things. This opens the door to a future of advanced technology including autonomous vehicles, smart cities, and advanced augmented/virtual reality (AR/VR).

Though we remain some way off autonomous vehicles becoming mainstream, they are growing in popularity as people realise their potential safety benefits. A critical challenge for autonomous vehicles is being able to visualise and interpret everything occurring in their surroundings in real-time, which demands extremely low latency.

Smart cities are another key area that 5G connectivity could make a more widespread reality. Pressures from congestion and pollution prior to COVID-19 have meant that city officials urgently need to take action to reduce climate change, which is where smart technology could come in to improve efficiency and reduce overall costs.

Reduced latency is also critical for AR and VR – anything over 20ms and users will experience nausea, but with 5G’s sub-5 or sub-2ms latency the user experience will be smooth, natural and realistic. Furthermore, both AR and VR applications can be very sensitive to network performance, with any interruption having a negative impact on user experience. 5G can handle thousands of devices and connections simultaneously and thus will bring us a major step closer to realising the vast potential that AR and VR offer industries including healthcare, entertainment and more.

What does the future hold?

The future is connected! Not only will 5G boost efficiency and transfer speeds, it will also enable us to explore exciting developing technologies well into the 2030s. 5G is part of all our futures, in both the short-term and long-term. Indeed, we are frequently asked for cabling solutions that surpass current speeds and frequencies, moving us to a world we can hardly imagine.

However, with significant change comes significant challenges that will affect us all. The cabling and interconnects are the focus of future innovation. Operating at mmWave frequencies since the mid-1980s, Junkosha foresaw the need for these high-end frequencies beyond that of military applications. With long sighted vision comes major breakthroughs; innovating the future through technologies for 5G will bring about a wireless network that will change the mobile telecoms space forever.