The use cases of mmWave technology in multi-gigabit connectivity, high-throughput satellite, automotive radar, and extended reality.
Forecasts show more than 29 billion networked devices by 2023 with M2M (machine-to-machine) connections representing half of the total. This type of communication needs to rely on very high transmission speeds and low latency to enable mission-critical applications such as self-driving cars and advanced driver-assistance systems.
Move up to mmWave
The mmWave radio spectrum is the part of the electromagnetic spectrum with frequencies from 30 to 300GHz. Until recently, frequencies used for communications were limited to the microwave band, typically 3–30GHz. Most commercial wireless networks use the lower part of this band—between 800MHz and 6GHz. The 3G/4G/5G cellular connection on your smartphone, your home Wi-Fi, the Bluetooth connection on your wireless headset, and almost anything you can think of, uses those frequencies to transmit information.
But while the number of users and devices consuming data increases exponentially, the radio spectrum frequency band available to telecom carriers has not changed. Each user is allocated a limited amount of bandwidth, leading to slower speeds and frequent disconnections.
One way to solve this problem is to transmit signals on bands where spectrum is readily available. The millimeter-wave (mmWave) band offers a huge amount of under-utilized bandwidth, frequency reuse and channel bandwidth—making it particularly suited for multi-gigabit mobile communication systems and high-throughput satellites. Components working in the mmWave bands are more compact and smaller in size, making them particularly useful in scenarios with a high density of devices operating simultaneously and in close proximity.
Those advantages make mmWave technology the way to boost performance of data transmission—the turbo of the information age engine. Here are four use cases where mmWave technology is the key enabler.
Multi-gigabit connectivity for capacity and speed
Satisfying demand for high-quality services for greatly increasing subscribers accessing mobile cellular networks, is essential for network operators.
More users and more connections mean stress on the network. But while we assume the air is used as a wireless transmission medium and does not have bandwidth limitation—it does.
If the number of connections increase and the network does not adapt to this new need, it’s like being at a big football game and not being able to call or message our friends due to the overwhelming number of users that want to do the same thing at the same time.
New technologies like 5G or Wi-Fi (802.11ay) are designed to overcome those challenges and guarantee what is defined as “great service in a crowd”. To meet anticipated data throughput demands, high frequency bands in the mmWave range need to be adopted to accommodate more users in a spectrum section still free of interference, and not yet allocated. The mmWave bands give information bandwidth allowing data transfer rates up to 10Gbps. This is comparable to optical fiber, and is a hundred time faster than current 4G technology.
Due to the properties of high frequencies in relation to atmospheric absorption, as you move to higher frequencies, transmission range gets shorter. Millimeter waves allow close-range communication up to 100m, rather than kilometers. In this scenario, frequency can be reused allowing simultaneously operating networks that do not interfere with each other. Technologies such as beamforming also increase cellular network capacity, improving the transmission efficiency by targeting the users.
Enabling more flexible satellite communications
Satellite Communications play a vital role in the global telecommunications system. More than 3,000 operational satellites are currently in orbit and more than 1,800 of them are communications satellites.
In the past two years, multiple commercial satellite operators have begun launching high-throughput satellite constellations. These next-generation satellites will be able to provide far more throughput—up to 400% more, compared to conventional fixed, broadcast, and mobile satellite services.
This significant increase in capacity is achieved by using a ‘spot beam’ architecture to cover a desired service area, as in a cellular network, in contrast to the wide beam used in traditional satellite technology.
This architecture benefits from a higher transmit/receive gain, permitting the use of higher order modulation, so to achieve higher data rate. Also, with a service area being covered by multiple spot beams, operators can configure several beams to reuse the same frequency band and polarization, boosting capacity where needed and requested.
Most of the high-throughput satellites in operation today work in Ku (12–18GHz) and Ka-band (26.5–40GHz), but frequencies are getting higher, with deployment on the way in Q and V-band (40 to 75GHz).
Taking advantage of mmWave resolution for automotive radar
Automotive radar is the most reliable technology for range-detecting an object’s distance and motion, including velocity and angle in almost all conditions. It uses reflected radio waves to detect obstacles behind other obstacles and has low signal processing requirements.
Automotive radar sensing technology, mainstreamed by the 24GHz narrow band sensors, is now rapidly evolving toward the high frequency 76–81GHz band and wide 5GHz bandwidth, offering superior range resolution and immunity to obscurants such as fog and smoke. The magnitude of improvement delivered by the higher frequency and wider bandwidth is significant, because the errors in distance measurement and minimum resolvable distance are inversely proportional to the bandwidth.
Transitioning from 24GHz to 79GHz delivers 20x better performance. With the smaller wavelength, resolution and accuracy of velocity measurement increases proportionally. Therefore, by transitioning from 24GHz to 79GHz, velocity measurements can be improved by a factor of 3x.
Another advantage of the transition from legacy 24GHz to 79GHz systems is gain in size and weight. With the wavelength of 79GHz signals being a third of a 24GHz system, the total area of a 79GHz antenna is one-ninth of a similar 24GHz antenna. Developers can use smaller and lighter sensors and hide them more easily for better fuel economy and car designs.
Beginning a new age of extended reality
Extended reality (XR) is an emerging term that encompass all the immersive technologies, including all the ones we already have – augmented reality (AR), virtual reality (VR), mixed reality (MR) and the area interpolated among them. XR will have exciting applications in diverse fields such as entertainment, medicine, science, education and manufacturing, changing the way we see and interact with the world around us, real or computer-generated.
While VR and AR applications already exist, adoption is slow, with the main reasons being bandwidth and latency, because today’s wireless networks place serious limitations on those applications, which can negate the user experience entirely.
Millimeter-wave technology as implemented in 5G with increased transmission bandwidth and low latency, will strengthen existing experiences and enable new ones, paving the way for mass adoption.
But, to provide a truly immersive AR, at least a tenfold increase in data rate is needed, and this still poses major challenges for 5G technology. With continued technology innovation, the mmWave radio spectrum will be pivotal in tackling those challenges for 6G.
6G will be the sixth generation of wide-area wireless technology, expanding the availability of frequency bands to terahertz (THz) bands, above the mmWave frequency range where 5G operates. 6G will also increase the data rate from 5G’s 20Gbps to 1Tbps. In addition, 6G will reduce the latency to less than 1ms. As a result, 6G’s traffic capacity will increase from 5G’s 10Mbps/m to a theoretical maximum of 10Gbps/m.
Holographic communication, tactile internet and fully immersive virtual/augmented reality are among other applications that this future technology will make possible, and once again, mmWave will be the engine of change, and probably the trigger of the beginning of a new age where creativity and imagination will play a central role in our existence.
Giovanni D’Amore leads the radio frequency and microwave products business at Keysight Technologies. He has held numerous positions across product lines with Hewlett-Packard, Agilent Technologies, and now Keysight Technologies. Giovanni is an engineer with a M.Sc. in electronic and telecommunication from the University of Palermo, Italy and authored several articles around microwave measurement techniques. He is a regular speaker at microwave conferences such as IMS and EuMW.