Making 5G Happen

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5G is big. Also known as 5G New Radio (NR), this new wireless technology will ultimately impact everyone in the electronics and telecommunications industries, not to mention the effect that it will have on us individually. 5G NR has been under development now for several years, and while progress is being made to finalize the standard, it is still years away before becoming what we call mainstream. Most estimates say 2020 is when we will ultimately see some real 5G deployments on a scale that will we will notice. In the meantime, companies are firming up their plans for whatever 5G products and services they will offer. Considerable hype still abounds, but real progress is being made. Here is a fresh assessment of 5G status.

What’s the Hurry? LTE is Great

Do we really need 5G right now? Our current 4G cellular standard Long Term Evolution (LTE) is adequately serving most of us right now. Are conditions so bad that we are anxious for the next generation to come along and relieve our suffering? I don’t think so. Virtually all cellular carriers now implement LTE that is delivering megabit speeds over most of the developed world.

In addition, the carriers are regularly updating their systems to add capacity or boost data rates. Many have already implemented LTE Advanced and are on the path to LTE Advanced Pro. These advanced versions offer features like carrier aggregation (CA) that combines up to five 20 MHz channels, increased MIMO configurations to 8×8, and modulation to 256QAM. These provide the potential for gigabit speed, although in reality hundreds of megabits downloads are more likely. Isn’t that enough? For some, probably not. Yet it is fine for the average masses. Video hogs always want more.

LTE is also now serving the need for some Internet of Things (IoT) applications. Yes, cellular is an option. The new LTE M1 and NB-IoT versions are being embedded into products. Most major carriers offer IoT or machine-to-machine (M2M) services that are typically manageable on existing networks. That application is growing.

Never satisfied, the industry is pushing ahead for something better. Isn’t that what we always do? Once a technology standard like LTE is finalized and commercially implemented we typically rush to top it with a new and better standard. It keeps us busy and challenged and pushes us to develop better hardware and software. How do engineers stay interested if they are not brainstorming then designing the next chips, products, and programs? We invent stuff even if we don’t need it, because revenue growth is a perpetual need.

LTE is more than satisfactory for now, and it will continue. 5G will not replace LTE.—it will serve a separate need and will complement LTE. Some call 5G an LTE overlay. You will not be wanting for good cellular service.

The 5G Rationale

Those pushing for 5G cite two major needs. First, everyone wants faster mobile broadband services on our smartphones and tablets. The key driving force is video. Audio is another major application. More cord-cutting and streaming. 4K and even 8K high definition video content is now available. We have become a nation of watchers and listeners, not readers. The smartphone makers are giving us bigger and higher resolution screens and faster processors to deal with our video-intensified life. The cellular operators are continually gearing up to provide the major pipeline for this coming video/audio glut.

Then there is the looming Internet of Things threat. We are already experiencing a significant increase in IoT connectivity, but more is coming. The predictions says billions more devices will ultimately need connections, and the cellular folks want a piece of that IoT and M2M business. LTE is dealing with it now, but 5G will greatly expand the potential uses.

For example, 5G will offer increased capacity and decreased latency for some critical applications such as vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communications for advanced driver assistance systems (ADAS) and self-driving vehicles. A 5G-based cellular V2X communications system could very will replace the long-approved DSRC radios that use the 802.11p Wi-Fi-like standard.

Cellular operators are also looking at the broadband wireless market to deliver high-speed internet service. 5G will allow carriers to offer fast internet service in competition with cable and fiber ISPs. With 5G, wireless speeds will be on par with those hard-wired services, giving them a new revenue stream.

No, we are not desperate for 5G, as LTE is adequate for now. But we will love 5G once it gets here.

Defining 5G

The 5G standard is not complete as this is written, but we do know some generalities. The overall goals are a user capacity of x100 over existing LTE capability, downlink data rates up to 10 Gb/s, and a latency of less than 10 ms. Here are the highlights of the proposed 5G standard to meet these goals.

• A variety of spectrum will be used. Much of it will be below 6 GHz. Each carrier has its own spectrum licenses that vary widely. For example, T-Mobile bought some 600 MHz spectrum for 5G use. T-Mobile can also use some existing 1.7 and 2.1 GHz space. Sprint will use its extensive 2.5 GHz spectrum holdings. The 3.5 GHz Citizens Broadband Radio Service (CBRS) now used by the military may see some 5G usage on a shared basis. But the major trend is to move to the millimeter wave bands to gain more bandwidth to support that gigabit speed target. In the U.S. the 28 GHz and 39 GHz bands will be the new operational space. AT&T, T-Mobile, and Verizon have committed to this spectrum. This new spectrum provides the much wanted bandwidth up to 1 GHz. However, these frequencies offer new challenges of radio wave propagation and wireless circuitry. This industry as a whole is stepping up to make the mmWave bands workable.
• A dense collection of small cells will supplement traditional basestations. These miniature cell sites will attach to light poles, the sides of buildings, and on other structures to get the height needed for reliable connectivity. Getting permissions to install the small cells is turning out to be a major problem and will no doubt slow implementation of full 5G networks. Providing power and backhaul are related issues. While fiber backhaul is preferred for its speed, it is more costly to install, making microwave or mmWave backhaul a better choice for many installations. Otherwise, the dense small cell strategy is sound and will complement the existing LTE cell sites. Combined these sites should provide the coverage needed to make our 5G dreams come true.
• The modulation will surely be some form of OFDMA, different from plain old LTE. The final variant has yet to be revealed. Also look for some other features like different OFDMA subcarrier bandwidths up from LTE’s 15 kHz to 30, 60, 75, 120, or 240 kHz.
• Adaptive modulation to 256QAM will be adopted.
• Time division duplexing (TDD) replaces frequency division duplexing (FDD) that requires twice the spectrum.
• New channel coding includes low density parity check (LDPC) for data and polar coding for control.
• Massive, multiuser MIMO and antenna agile beamforming will be a standard feature.
• Some carriers like Verizon will offer their own technical variant of 5G.

Be Thankful for the T&M Companies

Let’s all show our appreciation for the test-and-measurement companies that literally make it possible to create 5G. Without the ability to simulate and test new hardware and software, the 5G developers would be stalled or limited. We would not be nearly as far along in 5G development without frequency-related arbitrary signal generators, spectrum analyzers, vector signal analyzers, vector network analyzers, and oscilloscopes. The T&M companies are the real pioneers of 5G and their products make it possible for the rest of the developers to create, test, evaluate, and make final standards decisions. Some of the key challenges of 5G testing include the still-unknown version of the OFDM modulation, massive MIMO, channel simulation and estimation, and the clear need for extensive over the air (OTA) testing. Here are just a few of the many products that companies are offering to expedite the way to 5G.

Keysight Technologies’ contribution to the 5G test effort is its 5G RF DVT Toolset, an addition to the company’s network emulation solution (NES) portfolio. The Toolset is based upon Keysight’s UXM 5G wireless test platform. Its purpose is to ensure measurement traceability from prototyping to acceptance and manufacturing. The DVT Toolset software uses Keysight’s Test Automation Platform (TAP) to generate RF and radio resource management test cases. It is applicable to 5G NR, including mmWave frequencies and beamforming. Figure 1 shows some example uses.