by Jon Gabay for Mouser Electronics
Virtually everyone today has wireless service or access to it. Since the introduction of early analog wireless services to digital 3G and 4G, most depend on their wireless service provider and device to keep them connected to our fast-paced, real-time world. Now, 5G is flaunting its promises for next-generation speeds and performance, and engineers are looking at 5G connectivity to evaluate how it will fit into their designs and applications.
5G is not the only protocol and standard, or even the best suited for many specific designs and future products. Many mature and feature-packed wireless protocols, devices, and development modules are readily available off-the-shelf to rapidly get your design up and running as quickly as possible.
Although time-to-market is important, it is not the only constraint and driving force. In our wireless world, an entire ecosystem of devices and functions happily live in their own bands interacting with others in a lesser way. What standards and protocols are best suited for your needs depends on what type of creature you are in the ecosystem. Let’s review.
What do you really need?
Keeping up with the latest technologies lets one know what is possible, but not necessarily what is best. We all want global 1ms latency, and the 10Gbs data rates promised by 5G. But for our needs, is it akin to killing ants with atom bombs?
A mobile robotic surgeon performing lifesaving surgery being controlled and monitored by a doctor on the other side of the world in a fixed location will need low latency with high-speed bidirectional video and audio streaming, as well as haptic feedback and a multitude of sensors and actuators. Yes, 5G is suitable here, but a light switch in an automated apartment does not need the same.
Note that mobile or fixed location fits into the equation. Mobile designs typically have low-power constraints but might also take advantage of widely deployed wireless networks such as 3G, 4G, and 5G. Fixed-location designs might get power locally or even harvest energy from the environment, making long-haul connections wirelessly.
For example, a distributed sensor array deployed over a fixed area cannot bear the cost burden of making each sensor 5G. First, until very high volumes are in production, the design costs, time to certify, and added cost of each sensor’s required monthly service would make it infeasible. Instead, an alternative lower-cost, established wireless protocol can be used to allow each sensor to communicate with a single point aggregator. Faster to design and test because components, development kits, and open-source software already most likely exist. This can be center point star architecture or a mesh network. A lot will depend on the distances you need to traverse and the data rates.
Typically, large networks of distributed sensors such as environmental, geological, radiological, and so on will only transmit short bursts of data every so often. Even though the transmit power might be higher instantaneously, the average data rate and power are lower than a more closely spaced, higher data-driven design. Typically, latency should not be an issue either for our environmental sensor example.
Also, only a single aggregator or gateway is needed to make the entire network globally accessible. This reduces the service provider carrier costs tremendously. In this low-cost, low-data rate, long latency example, the aggregator can be 3G or 4G and perform admirably–especially because 3G and 4G are more widely deployed almost everywhere.
Back to basics
Time to market is paramount for many companies. Using newer technology is always riskier than going with a tried-and-true proven solution. Here, the more mature standards such as 3G and 4G present designers with more options and choices to tailor their designs to the parts and development environments that are readily available.
When implementing multiple wireless communications links inside a single device, other concerns come into play. Band overlap, shared antennas, metering power, beaconing, and listening characteristics need to be considered. This is doable.
We already have handheld wireless multiport communications with 3G/4G, Wi-Fi, and Bluetooth, for example, in our cellphones. And, thankfully, the ultra-high volume of cellphones manufactured paves the way for more robust and lower-cost technology we can all use. But few designers are designing cellphones, and many designers are designing IoT devices.
By its nature, the Internet of Things will add more connected devices to the globally accessible web. These can be ultra-simple things: light switches or ultra-mission-critical devices such as hospital ambulance vital stats links.
We mentioned vast environmental sensor arrays and automated and remote-control technologies such as light switches, temperature, and humidity sensors for living environments. Also, we have medical devices we will wear or might be implanted in us for use in therapy and exercise. Power plants, water-treatment facilities, traffic lights, factories, and self-driving vehicles are just a few examples that indicate such a range of demands on our designs and communications infrastructures.
The most common choices that are well established are Wi-Fi and Bluetooth. Wi-Fi is massively deployed, and most facilities, commercial, industrial, and consumer locations, have and offer Wi-Fi connectivity. It is a good choice for internal facilities to have multiple routers, bridges, gateways, and even mesh topologies, but the stadium issue persists.
When thousands of users converge in limited areas with limited bandwidth, channels, and sockets, degradation of services will occur. This is called the stadium effect. Think of everyone in a sports stadium (pre-COVID-19) streaming the game on their phones to a friend. At some point, the available bandwidth is exceeded, and service will be interrupted. The same is true for 3G and 4G services in proximity to cell towers that are already oversubscribed.
For IoT designs that must compete for time slices of bandwidth, perhaps an alternative protocol is more suitable. For example, ZigBee has been around for years, is supported by many device manufacturers, and has open-source code available. It is a mesh network topology that can span large distances using storage and forwarding of packets. It can coexist with 3G/4G/Wi-Fi and Bluetooth, creating an independent network with fewer devices and less required space. Security networks, for example, could benefit from such an undersubscribed network.
Long-distance subnetworks such as Long Range LoRa use a 915MHz band totally outside the 3G/4G/5G, ZigBee, Bluetooth, and Wi-Fi bands. This might be an ideal choice for vastly distributed topologies such as oceanic and seismic sensors (Figure 1).
The changing clouds
Although initially used for storage and backups, the cloud has evolved to become a server of applications to clients. This means that the applications and the data are stored remotely, and our cellular devices are mere terminals into the cloud window. Applications running in the cloud need only refresh our remote devices.
This has some benefits and some drawbacks. The benefit is that large data sets can be stored and retrieved when needed, meaning our devices free up local memory. Data transfers from cloud-based storage to cloud-based processing are entirely in the background, faster, and not wasting our time moving files around inside our devices.
This approach depends on connectivity. If you don’t have a local copy of your applications and data, you will be dead in the water if connectivity fails. However, this also opens the door for more sophisticated applications such as self-driving cars, drones, farm equipment, and maybe one day, jets.
Our handheld devices might not contain all the info on traffic, accidents, and detours, but the cloud can. This means high-end processing can take place transparently in the shadows, while tokenized commands and responses are all that is sent between the cloud and the end terminal device.
This can lower overall data needs, especially with the low latencies that 5G promises. It can also provide more data bandwidth to other critical infrastructure services such as high-resolution surveillance cameras widely distributed in cityscapes to find criminals or terrorists.
Overall, bandwidth and memory in remote handheld devices have a trade-off. At some point, even handheld devices will need large streams of fast data. Higher resolution displays, faster refresh rates, and applications such as immersive virtual reality multiply the amount of data and the required speed. For instance, a flat-screen in two dimensions might use 4K x 4K pixels. But a three-dimensional virtual-reality headset needs to store 360 degrees by 360 degrees of data to respond fast enough to head movements.
So, what does 5G give us?
Compared to 4G, 5G servers provide 1000 times more bandwidth. That alone is impressive, especially in light of the data-intensive applications we have been discussing. A primary benefit is the potential amount of traffic 5G can handle, and as the IoT heats up, more connected devices will be fighting for channel space.
5G claims the ability to handle 10,000 times more traffic, which, for the short term, will eliminate the delays associated with oversubscription and provide a structure for many more connected devices as the IoT gains steam. That’s 100 times more connected devices than 4G at its best.
The 10Gb/s max transfer speed of 5G is 10 times faster than the 1Gb/s data rates of 4G, but the latency differences are a real eye-opener. The 4G technology has 30ms to 70ms latency. This might not seem like much, but if you are a musician trying to practice with other musicians remotely through the network, it just doesn’t work. The variable delay times between all players will make the composite result out of sync.
The promise of 1ms latency for 5G makes it possible for the first time for musicians to play in sync distributed around the world. And, hopefully, the digital delay in voice conversations will stop driving us crazy.
These performance increases make it more feasible for self-driving vehicles to possibly adapt safely in real-time. I would feel more comfortable in a self-driving car going 112.63km/h if it monitored and adjusted its course every millisecond compared to 70ms. The same is true for drones, robots, and automated factories. Things will go wrong from time to time, and the reaction and response times can be the difference between safety and fatality.
One claim that has yet to manifest is that 5G devices will require 90 percent less power than comparable 4G devices. This will only be when 5G mini-cell towers are placed everywhere so that a device does not need to use so much transmission power to hit the tower. Even so, this means remote applications (such as seismic sensors) that use energy harvesting can function forever, barring damage.
When and where
It is interesting to note that 4G isn’t even deployed everywhere yet. In developing countries, landline wiring doesn’t exist, and the entire infrastructure for communications will be wireless. Designs using 4G technology are expanding, and many applications can do just fine with 4G connectivity.
Mature parts such as the SARA-R510M8S-00B from u-blox provide secure cloud connectivity through LTE-M wireless connectivity for present-day 4G. At 3.8V, it only draws 395ma while transmitting and is easily placed on a standard circuit board design (Figure 2).
While 4G towers are still going up, 5G retrofits to existing towers and 5G server towers will increase as equipment, devices, and demands increase.
Right now, 5G is simply serving as a fairly short-hop backbone link between high line-of-sight towers. But, as 5G chipsets and components emerge, you won’t have to be a cellphone manufacturer to get access to parts, development systems, and source codes.
For example, Analog Devices is making several key pieces of an integrated 5G system, such as the ADMV4801 RF transceiver and beamformer. Beamforming is a big part of 5G where the 5G server and the device can target and pinpoint emissions into a more powerful directional communications beam. This part operates in the 24GHz to 29.5GHz range and supports 16 transmitter and 16 receiver channels monolithically. The matched 50Ω input and output impedance makes it easy to interface with standard antennas and RF components. It retains memory for beam positioning that is useful for reestablishing communications with fixed point-to-point locations.
Coupled with the ADMV1017 5G up/down converter, it starts fitting the puzzle pieces together to form a viable and low-risk 5G embedded solution. Upconverter modes include direct (from differential baseband) or single-ended IF to RF sideband upconversion. It features down converters for direct, image reject, or single-ended complex modes as well.
A third part, the ADMV4821BCCZ (coming soon), will perform bolt-on 16-channel dual- or single-polarization beamforming using high-resolution vector modulation for phase control and features high-resolution amplitude control.
Keep an eye out for the eval unit, the ADMV4821-EVALZ, when ready to be the first kid on your block to create a 5G design. Understand that the learning curve for 5G might be a little longer than it was for 4G, and not as many resources or experts are available. Literature is still lagging, but expect to see good quality app notes coming out from major suppliers.
The 5G spectrum will be filling up with traffic as device manufacturers and service provides deploy more towers and infrastructure. With beam steering and power in the new frequency bands, it will need to be determined how safe this technology will be for organic creatures. This is a lot of focused power at wavelengths that could be mutagenic, though few nonbusiness-oriented studies have taken place.
Keep an eye on LPWAN technology as a subnet wireless companion since it coexists well with 5G. Unlicensed standards such as 3GPP’s Release 16 supports 5G New Radio (NR)-Unlicensed bands and other options exist, too.
Narrowband RF subsystems are always an option and have demonstrated the ability to handle 50,000 devices in arranged clusters. Narrowband can use less power and penetrate walls and floors more readily for those hard-to-reach places.
Stadiums, concert halls, and large gathering places can expect to see Wi-Fi-like private networks that live within the 5G space. New partitioning of the 5G space will most certainly be taking place to provide higher reliability and less interference for mission-critical applications such as self-driving vehicles, drones, power plants, and medical implants, to name a few.
Cluster networks based on Wi-Fi, 6LoPAN, Bluetooth, ZigBee, and so on will also be living in this ecosystem and will most likely aggregate to the 5G realm at some point. Clever partitioning and the using protocols and bands can determine the effectiveness of next-generation designs specially targeted for the IoT.
About the author
Jon Gabay is a contributing writer for Mouser Electronics. After completing his studies in electrical engineering, Jon Gabay has worked with defense, commercial, industrial, consumer, energy, and medical companies as a design engineer, firmware coder, system designer, research scientist, and product developer. As an alternative energy researcher and inventor, he has been involved with automation technology since he founded and ran Dedicated Devices Corp. up until 2004. Since then, he has been doing research and development, writing articles, and developing technologies for next-generation engineers and students.