Wireless/RF Technology for the Next Telecom Evolution

Advances in RF, connectivity, and software are critical to improving the functionality and scalability of real-time embedded systems for the internet of things (IoT) and industrial IoT. The growing demand by businesses for greater operating efficiency to support higher decision-making capabilities and lower costs is extending the wireless technology connectivity model into all vertical markets, such as smart grids and smart cities. New developments in radio architecture, circuit implementation, and semiconductor technology are enhancing integration to enable new products that serve the consumer and industrial sectors.

In a written exchange with EE Times Europe, Keysight Technologies’ Roger Nichols, 5G program manager, and Frederic Weiller, automotive and energy solutions lead, weighed in on the prospects and challenges for the relevant technologies in the wireless/RF market.

EE Times Europe: Power RF semiconductor technology is already present in many devices, such as RF power amplifiers. How do you see future market-share opportunities shaping up for the technology?

Roger Nichols: Power semiconductors have been growing in share for several years, with early work in laterally diffused metal oxide semiconductor (LDMOS) technology now evolving to significant growth in the use of gallium nitride (GaN). LDMOS has significant use in earlier technologies for plenty of relatively low-cost applications below 1 GHz. However, gallium arsenide (GaAs) is an “RF power semiconductor,” and virtually every phone made today for Generation 3 and beyond has a GaAs RF front end. Hence, the share of GaAs is significant and has been relatively steady for the past four years.

The growth in the use of GaN for mobile infrastructure (cell site) power amplifiers, especially in the large LTE [Long-Term Evolution] buildouts in 2012–2015, firmly established GaN in mainstream use, and the associated volume helped drive the costs down for broader commercial communications use. There are ongoing arguments about whether 5G technologies — especially those requiring “mid-band,” 3- to 7-GHz functionality and, of course, those requiring operation in the FR2 [frequency] bands of 24 to 52 GHz — can afford the use of more expensive RF power compound semiconductors (III–V). So the question is, which parts of the volume are driven by silicon and/or silicon germanium (SiGe), or by GaAs or maybe even GaN? The answer will be a mix.

Silicon is the least expensive and the most mature in terms of process and packaging technology. The technology associated with building arrays of amplifiers, each associated with a subset of antennas in an antenna array, allows for gain not possible with single elements associated with single amplifiers. Silicon-based phased-array antenna technologies are showing promise in some 5G applications, even in the FR2 bands. But 5G will drive investment in frequency bands from as low as 600 MHz up to and including at least 47 GHz. The link budget (the RF power budget allowed between transmitter and receiver to ensure adequate signal-to-noise ratio at the receiver) for new commercial radio bands between 3 and 7 GHz is proving to be challenging, driving even more need for efficient power amplifiers and low-noise receiving amplifiers. And electrical power consumption is both a major cost issue for mobile operators and a battery capacity issue for those designing mobile user equipment.

Millimeter-wave (mmWave) network analyzers allow you to fully characterize interconnects and active devices such as amplifiers, mixers, and frequency converters at sub-6-GHz and mmWave frequencies. (Image: Keysight Technologies)

III–V technologies, such as GaAs and GaN, yield amplifiers with much higher efficiency, so despite their cost, yield, and technical challenges, there will be a growing demand for these. Keysight has been involved with helping our customers design and test devices from these and other processes for decades. We have our own III–V fabrication and packaging technology for RF power semiconductors for use in our own test equipment. We expect this [activity] to continue as a growing opportunity both as we advance our own processes and as we help our customers do the same.

EETE: The telecommunications sector is approaching adoption of the 5G wireless standard. This will surely increase the efficiency of the devices, thanks to a data transmission speed far superior to that of 4G. How do you gauge the potential of this emerging technology? What will it take to establish 5G on a large scale?

Nichols: The vision for 5G is much more than advances in data transmission speed. “Amazingly fast” is only one of the five vision phrases that have been part of the 5G lexicon for over five years. The others are “great service in a crowd,” “super real-time and reliable communications,” “best service follows you everywhere,” and “ubiquitous things communicating.” The potential is much more than a super-fast movie download or a better video game experience. Other areas of focus for 5G include a massive increase in the system’s capacity, not just to increase the number of users and devices but to handle a large variety of applications — ranging from those with a very large number of low-data-demand connections to those with fewer connections but significant demands on data speed. And the additional focus on low latency and very high reliability opens the use of commercial wireless networks to businesses that would otherwise not consider them.

Even more important is the design of 5G networks to be far more flexible with a much larger portion of network functionality implemented in software. This will allow a physical network to be virtually “sliced,” with different slices applied to different application sets. For example, one slice of the network would be for traditional mobile broadband use, and another may be used for a high-reliability or low-latency application related to facilitating automated transportation. The potential is for a much wider array of businesses and applications to utilize the network and to open up new business models for network operators and their respective supply chains.

So what will it take? There are three typical areas of focus to establish a new generation of wireless networks. All of these are based on a foundation of policies and standards that collectively enable the technology to be established and rolled out. First, the network itself needs to be built, and this has to happen while keeping the legacy network running smoothly. Second, the users, whether they are people or machines, need user equipment and devices to connect to the network. Third, the software and business models for new applications must be developed and enhanced. Altogether, these take years to establish.

The first commercial “production” 5G networks were switched on in late 2018, and more are coming in the next few months. As in all prior generations, these [deployments] start in just a few and limited geographic areas and grow from there. Keysight has been working with the industry to enable the research, development, trials, and launch of 5G since 2013. We are very excited to see these first systems up and running and will continue to be part of the evolution of this generation.

EETE: The success of self-driving vehicles is closely linked to sensors — for example, radio detection and ranging (radar) and light detection and ranging (LiDAR) — and connection technologies. How can the 5G wireless protocol enable enhanced, more efficient connections between autonomous vehicles?

Frederic Weiller: As autonomous driving, the connected car, and the evolution of 5G continue to gain momentum, wireless communication technologies are playing a critical role in keeping the entire ecosystem of vehicles, infrastructure, and pedestrians in sync. To enhance road safety and reduce the number of accidents, which may become even more challenging with the onset of autonomous driving, there’s a pressing need for vehicles to observe what’s happening around them, predict what’s about to transpire, communicate with each other, and take proactive safety measures.

The automotive ecosystem integrates a wide variety of wireless technologies that make roads safer by allowing vehicles to share and receive signals seamlessly. The technologies include:
• Advanced driver-assistance systems (ADAS), which are referred to as the “brain” of the car. These systems help automate the driving process by using immense compute resources, sensor fusion, machine learning, and path planning;
• Sensor fusion with radar, LiDAR, and optical sensors (cameras);
• High-speed information systems integrating automotive Ethernet networking, powerful signal processing, high-definition mapping with high-precision navigation, and artificial intelligence.

Vehicle-to-everything, or V2X, is a wireless communication system that enables vehicles, roadside infrastructure, and vulnerable road users to be interconnected and to communicate with each other. While dedicated short-range communications (DSRC) has benefited from an early start, the table shows how cellular V2X is not only catching up but positioning itself well for the future.

Cellular vehicle-to-everything (C-V2X) is currently based on 3GPP Release 14 LTE-A Pro cellular modem technology. Today, LTE-V2X, which is the initial version of C-V2X, is on the verge of commercial launch and will allow vehicles to communicate with each other and their surroundings.

C-V2X technology currently relies on 4G LTE, but its transition to 5G is already in development. With 5G-based V2X, information from sensors and other sources will travel through 5G’s high-bandwidth, low-latency, high-reliability links, paving the way to fully autonomous driving.

EETE: To what extent are the reliability and safety of a self-driving system influenced by the integrity of vehicle interconnection signals?

Weiller: V2X wireless builds on other communications technologies to take autonomous driving to the next level, augmenting the object-detection capabilities of advanced technologies such as radar, LiDAR, and camera sensors. V2X improves overall situational awareness by offering an increased electronic horizon to support soft safety alerts or graduated warnings, such as “reduced speed ahead.”

Comparison of DSRC and cellular V2X technologies *V2V = vehicle-to-vehicle, V2I = vehicle-to-infrastructure, V2N = vehicle-to-network, V2P = vehicle-to-pedestrian

V2X provides see-through, 360° non-line-of-sight awareness and extended range to enhance the functionality and safety of autonomous driving. Non-line-of-sight awareness is particularly valuable at night and in bad weather conditions. V2X also conveys intent by sharing sensor data and path planning for a higher level of predictability in situations like road hazards or sudden lane changes.

The following applications are possible thanks to wireless communications:
• Vehicle-to-vehicle (V2V), in which vehicles communicate directly to share pre- and post-collision warnings, near-real-time road conditions, blind spot warning, and visibility enhancement;
• Vehicle-to-network (V2N), in which vehicles communicate with a wireless network infrastructure made up of base stations and remote radio heads to share real-time traffic data;
• Vehicle-to-infrastructure (V2I), which lets vehicles communicate with infrastructure elements such as traffic displays, emergency terminals, and street lights to share traffic information;
• Vehicle-to-pedestrian (V2P), which provides safety alerts to pedestrians and cyclists.
C-V2X currently runs on 3GPP R14, providing basic safety measures such as forward-collision warnings and basic platooning, which is when autonomous vehicles communicate with each other to travel very closely together, safely, at high speed.

In the next release of C-V2X R14, targeting enhanced safety, the technology will evolve to extend its electronic horizon. Targeting enhanced safety, it will provide more reliability and non-line-of-sight performance, such as blind curve hazard warnings.

Keysight’s E8707A radar target simulator helps automotive electronics manufacturers confidently simulate radar targets in various realistic scenarios. (Image: Keysight Technologies)

In the future, the C-V2X R15+ release will provide advanced safety for autonomous driving in real-world conditions. This will include high-throughput communications for sensor sharing, partially to support highly automated driving and cooperative driving. Advanced LTE and 5G-based wireless technologies are the key technological building blocks for making autonomous driving a reality. As C-V2X developers race toward the future of autonomous driving, they must overcome design and performance verification challenges.

It’s no small feat, but the path remains clear: All innovation must begin and end with stringent, comprehensive, state-of-the-art testing during design and manufacturing to ensure the highest level of safety-critical performance, interoperability, and security in order to enhance road safety and reduce the number of accidents. ■