5G has little to do with the classic mobile communications as we know it. Unlike previous technologies like 4G, there is not a uniform 5G network. It is more than an evolution of previous technology; it is a whole set of new networks for different applications.
That makes the entire topic a little confusing, but the promises of 5G standard are great. Maximum speeds of up to 20 GB/s, minimization of the signal propagation time (latency) and many simultaneously mobile devices per area let all wireless experiences seem instantaneous and opens the doors for new applications. For some of us, nothing will change apart from quicker video streams and a more realistic gaming experience, but during this time unidentified use cases are being developed.
So, what is 5G? And what do designers and engineers need to know in order to take advantage of this technology?
5G standardization process
5G is an umbrella term covering various networks, technologies, and applications. It is a standardization for mobile communication. The name 5G was coined from the International Telecommunication Union (ITU) as a “fifth generation mobile communications system.” To this end, the standardization organization 3rd Generation Partnership Project (3GPP) is advancing its 5G implementation with the International Mobile Telecommunication (IMT-2020) initiative. In parallel, other standardization bodies, including the Institute of Electrical and Electronics Engineers (IEEE) and the ITU, are working on a 5G specification. In late 2019 the standardization process was finalized, and we now see more and more applications being commercialized.
Different applications require different antennas
There are many applications that are addressed with the new communication standard and there are multiple frequency ranges for 5G mobile communication to be considered. In general, 5G mobile networks can operate in various frequencies and hence requiring different antennas for different frequency bands.
5G frequencies, reach, and applicationsIt gets clearer when we pick some 5G frequency bands from the so-called multi-layer spectrum and align them with an application.
The coverage area: Below 2 GHz (for example 700 MHz) is suitable for indoor and broader coverage areas as the electromagnetic wave at this wavelength travels far and through objects.
The C-band: 2–6 GHz combines coverage, capacity, and the so-called “super data layer.” The frequencies larger than 6 GHz (e.g., 24–29 GHz and 37–43 GHz) provide a high bandwidth but require a direct line of sight as even leaves on trees can block the connection.
As various frequencies are used to transport a signal for different applications, specialized antennas and antenna concepts are required. So, the variation of frequency bands used for the communication are one reason why we see more antennas. The specialty of the New Radio (NR), requiring Line of Sigth LoS is the other reason why we see more antennas.
5G NR works differently than 4G
As the demand for frequencies continues to grow, federal communication agencies (such as the FCC in the U.S.) are reallocating free or vacant frequency ranges. By re-framing, already allocated frequencies for 5G are granted the operating license. The network operators are therefore free to decide which mobile communications technology they want to use.
The expiry of the UMTS frequencies in the 2 GHz band at the end of 2020 and 2025 will allow these frequencies to be allocated for 5G beginning in 2021 and going through 2026 (60 MHz in total).
Worldwide there is the unused 3.5 GHz band left behind by WiMax technology. As a result, in 2022, 300 MHz bandwidth will become available in the 3.6 GHz band and frequencies will range between 3.7 and 3.8 GHz.
The NR uses the mmWave range (millimeter waves) and starts at 24 GHz and extends up to 52.6 GHz. Possibly parts from the 64 to 86 GHz range will also be added in future.
But most of the frequencies intended for 5G (3.5 GHz, 26 GHz and above) are only suitable for a short range due to the physical propagation conditions of the radio signals. However, these frequency ranges have a high bandwidth potential. Low powered base stations, called femtocells, can be used to operate mobile radio hotspots with very high data rates. This means that more base stations are required. So, it may be that at some point streetlamps will provide not only light but also access to mobile Gigabit internet by hosting base stations for femtocells.
4G network compared to a 5G urban installation with active directive antennas.Antennas don’t look like antennas anymore
Higher frequencies for 5G are great for a number of reasons, one of the most important being that they support a huge capacity for fast data. They are highly directional and can be used right next to other wireless signals without causing interference. This is very different than 4G towers that send signals in all directions, potentially wasting both energy and power to beam radio waves at locations that aren't even requesting access to the internet.
5G NR uses shorter wavelengths due to higher frequencies, which means that antennas can be much smaller than existing antennas while still providing precise directional control. Since one base station can accommodate many directional antennas, it means that 5G can support over 1,000 more devices per meter than what 4G can accommodate. This means that 5G networks can beam ultrafast data to a lot more users, with high precision and little latency.
However, most of these super-high frequencies work only if there is a clear, direct line-of-sight between the antenna and the device receiving the signal. And some of these higher frequencies are easily absorbed by humidity, rain, and other objects, meaning that they don’t travel as far.
5G array antenna mounted on a base stationIt’s for these reasons that a strong 5G connection could drop down to 4G speeds when you walk just a few feet away. One way this is addressed is by using strategically placed antennas, either really small networks in specific rooms or buildings that need them, or large networks positioned throughout a city.
As 5G expands, there will likely be many repeating stations to push the radio waves as far as possible to provide long range 5G support.
Another difference between 5G and 4G is that 5G networks can more easily understand the type of data being requested, and are able to switch into a lower power mode when not in use or when supplying low rates to specific devices, but then switch to a higher powered mode for things like HD video streaming.
Enable better beamforming
Beamforming is an active antenna technology that uses directional radio links to supply individual mobile devices simultaneously and selectively with high bandwidth.
Use of higher frequency ranges makes multi-antenna systems necessary. The higher the frequency, the worse the conditions under which the electromagnetic waves are propagated. Multi-antenna systems and beamforming can partially counteract this. Beamforming enables the spatially targeted transmission and reception of radio signals. The more Dipoles (antenna elements) are available, the better beamforming works.
Massive Multiple Input Multiple Output (MIMO) - 5G mobile radio transmission technology
Unlike previous generations of mobile communications with GSM, UMTS and 4G/LTE, 5G does not have to undergo fundamental technical changes. In addition to the existing LTE technology, further systems and infrastructure are added, for example, to achieve higher data throughput and lower latency. Key elements of the 5G NR infrastructure are the active antenna arrays, allowing multi-user MIMO technologies. These antenna modules use beamforming for targeted radio contact with the receiver.
Simulation of a 5G massive MIMO array antenna in a network environment. Beamforming antenna pattern superposed with real installation.Arrays of extremely small antennas with high directivity can provide individual mobile devices with a high transmission rate. In the latest 3D MIMO and massive MIMO devices, several transmitter and receiver units are in one terminal device.
5G channel and network deployment – simulating how many antennas are needed
Mobile and base station antenna patterns can be simulated and then further used for high-level system analysis of the 5G radio network coverage and to determine channel statistics for urban, rural, and indoor scenarios.
5G on a factory floor. 5G base station antenna pattern simulation for further use in a high-level system analysis of the 5G radio network coverage.Altair Feko™ with WinProp modelling has been extensively used for 4G/LTE network planning. However, the use cases for 5G networks will be even more relevant largely due to the different factors that occur in the millimeter band. These include higher path loss from atmospheric absorption and rainfall, minimal penetration into walls, and stronger effects due to surface roughness.
In addition to being able to calculate the angular and delay spread, WinProp also provides a platform to analyze and compare the performance of different MIMO configurations while taking beamforming into account.
5G mobile communications applications and outlook
5G is an important mobile platform for the networked society, which must meet different broadband requirements. Many expect that 5G will lead to a modern industrial revolution. Much is expected from 5G mobile technology, and it is assumed that 5G will create the foundation for future applications like:
- Digital home
- Industry 4.0
- Internet of Things
- eHealth and mHealth
- Mobile TV / 5G broadcast
- Real-time communication (tactile communication)
- Autonomous driving
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