An Overview of 5G: What You Need to Know
5G will significantly improve mobile wireless. Standards aren’t defined yet, but technologies exist that may provide answers to the (overly?) optimistic demands placed on 5G. Who is in charge? What can 5G do? What are the technologies behind it, and when it will be here?
The agency behind 5G is the International Telecommunication Union (ITU), an agency in the United Nations that coordinates telecommunications throughout the world. The ITU Radiocommunications Sector (ITU-R) is in a years-long process of creating a 5G standard called the International Mobile Telecommunication system for the Year 2020 (IMT-2020). The creation of the IMT-2020 has the support of numerous companies, initiatives, workgroups, and industries. Generational mobile wireless technologies have been developed by a standards body, the 3rd Generation Partnership Project (3GPP), which is overseeing the development of 5G with a mind to the vision and planning of the IMT-2020. As the 3GPP states it, “The introduction of 5G will be the result of improvements in LTE, LTE-Advanced and LTE Pro, but this will soon be followed by a major technology step, with the prospect of an entirely new air interface. The first drop of ‘New Radio’ features, in Release 15, will form the first Phase of 5G deployments[i].”
A majority of smartphones in the U.S. are presently serviced by LTE or 4G standards for high-speed mobile wireless communication. 3G enabled the first smartphones to receive web pages, videos, and streaming music. 4G enables streaming high-definition video. 5G is next, and is purported to be so fast, with speeds of up to 10Gbps, such that you can download a feature-length HD movie in a few seconds. London-based research firm IHS Markit indicates that by 2035, the worldwide 5G value chain will be generating $3.5 trillion and 22 million jobs.[ii]
5G is getting a lot of hype, even though it has yet to be defined. The experts do not know what particular technology will be used to arrive at what everyone is wishing for, and calling, 5G. Furthermore, public speculation on the problems that 5G will solve and the new solutions it will bring are a bit dangerous for consumers, since there is no 5G logo for certification, such as what we have for Universal Serial Bus. Marketers could very well add some features to 4G/LTE and market them as 5G. Nevertheless, 5G is exciting for what it will enable. At CES 2017, Qualcomm CEO Steve Mollenkopf said, “5G will have an impact similar to the introduction of electricity or the automobile. In 2035, when 5G’s full economic benefit should be realized across the globe, a broad range of industries from retail to education, transportation to entertainment, and everything in between could produce up to $12 trillion worth of goods and services enabled by 5G.”
Data traffic from both Wi-Fi and cellular connections is forecasted to make up two-thirds of total IP traffic by 2020. Global monthly IP traffic will reach 25 GB per capita by 2020, up from 10 GB per capita in 2015. Smartphone traffic will exceed that of personal computers by 2020[iii]. Many industries will be enabled to do more and create new markets with 5G, which will service safety-critical and high-data-volume markets such as driverless cars that communicate with each other (known as Vehicle-to-Vehicle, or V2V) and with infrastructure (V2I). An example would be for cars to communicate a three-car highway pile-up ahead in heavy snow or fog. V2V-cars in the pileup could communicate their status to approaching V2V-enabled cars, giving drivers or their automatic systems a chance to slow down or give warning. V2I technology would be something like signs and cameras that wirelessly communicate information to smart cars, such as speed limits or detour routes resulting from accidents or construction. Another example of an application that could really use 5G to reach full potential is unmanned aerial vehicles (UAVs). UAVs, or drones, already communicate via satellite within expensive military applications, but for widespread commercial use in delivering packages or streaming live video drones need a means of communicating instantly. With such low latency, it’s possible that real-time, or “life-like” response times could enable remote surgery or immersive experiences in virtual reality. This kind of real-time, data-heavy, ultra-reliable, ubiquitous wireless communication is not possible with 4G, and many are wondering how technology will transform carriers to 5G. If 5G becomes what it is chalked up to be, it will change lives dramatically. However, it will take years before anyone can say, “We have full 5G.”
Many Paths to 5G
The frequency spectrum is getting crammed with signals as more products use the air waves. Currently most devices are using the spectrum 700MHz and 3GHz and to a lesser extent up to 6GHz. The FCC has opened up the spectrum to make way for 5G. However, it may be that no single technology will be able to fill the 5G boots alone, and 5G will arrive as incremental improvements, layering different technologies to get around multiple, concurrent obstacles. New frame structures, modulation, massive Multiple-Input Multiple-Output (mMIMO), beamforming, and other technologies are being investigated[iv]. The most prominent technologies under consideration for 5G appear to be: millimeter waves, small cell, massive MIMO, beamforming, and the use of full duplex.
The 24 GHz – 300 GHz Band: Millimeter Waves
Technically, millimeter waves (mmWaves) define the 24 GHz – 300 GHz band. In 2016, the Federal Communications Commission (FCC) moved to open almost 11GHz in the “Frontier Spectrum” located above the 24GHz band, anticipating 5G development[v]. The FCC opened up a vast range of high-band spectrum for 5G: 3.85GHz of licensed spectrum and 7GHz of unlicensed spectrum. A 3GPP working group defines new radio (NR) access that is flexible enough to support from less than 6 GHz up to 100GHz. One of the major challenges with mobile communications’ use of millimetre-wave signals is their short range. IBM Research and Ericsson have teamed up to create a phased array design that supports beam-steering with a resolution of less than 1.4 degrees; a high precision beam is pointed towards users.
“Small cells” have been available for years, especially for use in isolated or rural areas, and are essentially miniature base stations. Yet versions called femto cells can be purchased at big box electronics stores to improve indoor cell phone performance in rural areas or carrier “dead zones.” These FCC-certified devices can work with all carriers and 2G, 3G, and LTE/4G signals. Small cells optimize performance by increasing the network density needed for large amounts of data capacity. They bring the network closer to the user regardless of location and will be mounted indoors and outdoors on common infrastructure like lamp posts.
Massive Multiple-Input Multiple-Output (mMIMO)
Massive MIMO (mMIMO) is a “smart” antenna system already used in LTE/4G as well as WiFi that uses two or more receivers and transmitters to communicate more data at the same time, increasing capacity without using more spectrum. Massive MIMO has many antennas on a single array. The idea with mMIMO is to communicate in a deluge of signals coming from dozens of antennas on a cell tower and multi-path propagation is exploited so that total link capacity is increased. MIMO transmitters send multiple data streams via multiple transmit antennas, achieving more capacity without using more spectrum by effectively transmitting orthogonally polarized waves. Signal processing and system design complexity increases with the increase in number of antennas, as each receiving antenna must be able to distinguish separate data from each antenna. An 8 x 8 MIMO would have 8 transmitting and 8 receiving antennas. mMIMO offers a 10x increase in capacity and a 100x increase in energy efficiency[vi]. Millimeter-wave frequencies up to 64 x 64 MIMO may be required.
Beamforming is still on the table as an option for implementing 5G. Beamforming allows one to steer the transmission of signals. Beamforming is a concept common to ultra-sound technology commonly used in health care to determine the growth of a baby in-utero. Beamforming uses directionally controlled waves and for 5G, advanced antennas. Combining mMIMO with beamforming gives you laser-focused mMIMO; the beams become more narrow. A beamformed signal might serve several users in a given area and change direction thousands of times a second to service each individual user.[vii] Beamforming mitigates some of the issues for millimeter-waves, which get weaker with distance, by concentrating the signal at the user. User location is needed for beamforming to work and might be determined by projecting a trajectory for the moving user based upon received signals.
Full duplex refers to using a single channel to both send and receive at the same time without interference. Toy walkie-talkies are single-duplex. Cellular technology today uses two frequencies to achieve the effect of full duplex, a method called half-duplex: one frequency channel sends while the other frequency receives, so that interrupting one another in a conversation is possible. Actual full duplex can save one channel and free up spectrum. However, interference while using the same frequency band is a known problem. Special circuits with the ability to cancel self-interference will be necessary, possibly by intercepting and separating uplink and downlink signals via use of orthogonal signaling in the frequency or time domains[viii].
The complicated terminology above is a tiny foreshadowing of the immense complexity in using all techniques in tandem to create the symphony that is 5G.
Pieces of 5G Are Already Here: Verizon’s 5GTF
Adam Koeppe, Vice President of Network Planning at Verizon, said, “Network density is increasing to meet the demands of customers, and following the FCC’s aggressive action on 5G spectrum, the time is right to deliver the next generation of broadband services with 5G.” Mobile wireless technology has seen incremental improvement for decades. The “G” may stand for generation, but unlike the baby boomer generation, cellular technology is never rolled out all at once. Major advances are already taking place within 4G, including LTE-Advanced and LTE-Advanced Pro. In mid-2016, Verizon was the first carrier to deploy LTE Advanced in the U.S., providing peak speeds up to 50% faster than prior to improvements. LTE Advanced utilizes carrier aggregation, remote electrical tilt antennas, and 4 x 4 MIMO.
Verizon has 5G trials underway, begun in 2016, with fixed wireless access (point-to-point wireless). If the trials are successful, then cable and fiber could be replaced with wireless 5G in between buildings as a starting point. Intel has announced a 5G modem baseband chip that pairs with a new 5G transceiver enabling both sub-6 GHz and millimetre-wave capabilities. Together, the chipset uses 3GPP-defined, 5G NR (new radio) technology with low latency frame structures, advanced channel coding and massive MIMO[ix]. Products like Intel’s 5G Modem support the 3GPP NR specification and Verizon’s 5G trials can help drive global adoption of the 3GPP 5G standard. By mid-2017, Verizon plans to deliver fixed wireless 5G service to select pilot customers in the U.S[x].
5G looks like the wild west at present: Several companies, organizations, and alliances are working in many different technologies that may eventually be patched together as a system of overlapping technologies. Someday our dream of 5G will happen, but it is a massive undertaking and will require several industries to cooperate where the seams meet for several complex technologies. The final 5G may be the greatest thing since electricity and could be the basis for a critical digital infrastructure that underpins the national economy. It can take a decade or more to get the promised 5G into a seamless, coverage-consistent, mobile wireless communications infrastructure that we can count on. One has to applaud the 5G technology innovators who aren’t waiting for the paint to dry on 4G before tackling 5G.
Lynnette Reese is Editor-in-Chief, Embedded Intel Solutions and Embedded Systems Engineering, and has been working in various roles as an electrical engineer for over two decades. She is interested in open source software and hardware, the maker movement, and in increasing the number of women working in STEM so she has a greater chance of talking about something other than football at the water cooler.
[i] “About 3GPP,” http://www.3gpp.org/about-3gpp Accessed Mar 7, 2017.
[ii] The 5G Economy – How 5G technology will contribute to the global economy,” IHS Markit. Web access. March, 2017.
[iii] “Wireless Technology Evolution Towards 5G: 3G Release 13 to Release 15 and Beyond.” White Paper. 5gmericas, Feb. 2017. Web. 6 Mar. 2017.
[iv] “Wireless Technology Evolution Towards 5G: 3GPP Release 13 to Release 15 and Beyond.” White Paper. 5gmericas, Feb. 2017. Web. 6 Mar. 2017.
[vi] E. G. Larsson, F. Tufvesson, O. Edfors, and T. L. Marzetta, “Massive MIMO for Next Generation Wireless Systems,” IEEE Communications Magazine, vol. 52, no. 2, pp. 186-195, February 2014.
[vii] Claes Tidestav, “How can you get all users in high rise buildings >200 Mbps throughput wherever they are, and reduce network energy consumption at the same time? Through advanced antennas, flexible, user-specific beamforming and a new mobility algorithm,“ March 19, 2015. Web. 6 Mar 2017.
[viii] Zhang, Chai, Long, Vasilakos, Hanzo, “Full duplex techniques for 5G networks: self-interference cancellation, protocol design, and relay selection,” 14 May 2015. Web. 6 Mar 2017.