5G Technology: 5G mobile communications

5G Cellular Technology Tutorial Includes:
5G Technology     5G Requirements     5G NR, New Radio     5G NG NextGen Network     5G waveforms & modulation     5G multiple access scheme     5G mmWave     Massive MIMO & beam-forming     Frequency bands & channels     Data channels: physical, transport & logical     Voice over New Radio, VoNR    

The 5G mobile communications system provides a far higher level of performance than the previous generations of mobile communications systems.

The new 5G technology is not just the next version of mobile communications, evolving from 1G to 2G, 3G, 4G, but it provides a new approach giving ubiquitous connectivity.

5G technology is very different. Previous systems had evolved driven more by what could be done with the latest technology. The new 5G technology has been driven by specific uses ad applications.

5G mobile communications has been driven by the need to provide ubiquitous connectivity for applications as diverse as automotive communications, remote control with haptic style feedback, huge video downloads, as well as the very low data rate applications like remote sensors and what is being termed the IoT, Internet of Things.

5G is able to provide much greater flexibility and therefore it is able to support a much wider range of applications, from low data rate Internet of Things requirements through to very fast data rate and very low latency applications.

5G standardisation

Like all widely used systems, the 5G mobile communications is governed by a series of standards. Building on 2G GSM, 3G UMTS and then 4G LTE, the 5G standard come under the auspices of 3GPP - Third generation Partnership Project.

3GPP has a number of different work groups, each addressing different elements of the required standards. They draw on industry expert who give of their time and are sponsored by relevant mobile communications companies. In this way the standards are written and developed.

By having a main industry organisation that controls the standards, interested parties are able to influence the standards to ensure that the required functionality is obtained. Also as the standard are international not only can different companies work on different elements of the system and know they will interoperate, but also for the user, capabilities like roaming are available, and the cost of phones, calls, etc are reduced as a result of the savings of scale, etc.

The 3GPP standards are updated as specific releases - each release refining elements that have already been described, and introducing new functionality. Previous releases contained the standards for GSM, UMTS and LTE. As 5G started to be developed, it too was incorporated into the standards.

The new releases also contain updates for previous systems - Release 14, for example contained many new elements of functionality for LTE as well as updates etc, for UMTS and GSM.

5G cellular systems overview

As the different generations of cellular telecommunications have evolved, each one has brought its own improvements. The same is true of 5G technology.

• First generation, 1G:   These phones were analogue and were the first mobile or cellular phones to be used. Although revolutionary in their time they offered very low levels of spectrum efficiency and security.
• Second generation, 2G:   These were based around digital technology and offered much better spectrum efficiency, security and new features such as text messages and low data rate communications.
• Third generation, 3G:   The aim of this technology was to provide high speed data. The original technology was enhanced to allow data up to 14 Mbps and more.
• Fourth generation, 4G:   This was an all-IP based technology capable of providing data rates up to 1 Gbps.
• 5G technology:   When 5G was being first postulated a number of use cases were put forwards: very high speed data transfer as video downloads become larger and more commonplace; remote control with low latency - examples of autonomous vehicles communicating with rad infrastructure to provide safe transport as well as the example of experienced surgeons being able to perform delicate surgery remotely using a 5G link both of these examples require very low latency mobile communications; more capability for general data communications; ability to accommodate the very low data rate and occasional communications for the Internet of Things, IoT where very long battery life is needed.

Rather than just offering more of what was in the previous mobile communications generations, 5G technology needed to offer new capabilities and ubiquitous connectivity. This would require not only the use of exiting base stations which could be converted to 5G, but also many more small cells as well.

5G requirements

As the preliminaries for the work for the new 5G mobile communications system, the outline requirements were set in place. These were A defined by the ITU as part of IMT2020. Even now with 5G as an active mobile communications system, it is useful to refer to these requirements.

5G communications system

The 5G mobile cellular communications system is a major shift in the way mobile communications networks operate. New network topologies, access networks and the like were defined and implemented.

• 5G New Radio, 5G NR:   5G new radio is the new name for the 5G radio access network. It consists of the different elements needed for the new radio access network. Using a far more flexible technology the system is able to respond to the different and changing needs of mobile users whether they be a small IoT node, or a high data user, stationary or mobile.
  Read more about . . . . 5G New Radio, 5G NR.
  
  
• 5G NextGen Core Network:   Although initial deployments of 5G utilised the core network of LTE or possibly even 3G networks, the network needed to move to a much flatter structure to provide the data capability and low latency needed.
  
  Read more about . . . . 5G NextGen Core Network.
  
  

5G technologies

5G also incorporates many technologies, many of which are new, to enable the it to provide the very high levels of performance required of it.

The technologies for 5G mobile communications include:

• Waveforms & modulation:   One of the major discussions when 5G was being developed was based around the type of waveform to be used. In the end the scheme was based around OFDM, with actual modulation formats dependent upon the link and these include QPSK, 16QAM, 64QAM, 256QAM and for the uplink when DFT-OFDM is used, π/2-BPSK can be used.
  
  For the future, other forms of waveform may be developed, but currently the waveform is based around OFDM.
  
  Read more about . . . . 5G waveforms & modulation.
  
  
• Multiple Access:   Again a variety of access schemes were discussed, but for the 5G New Radio, OFDMA was implemented. For the downlink CP-OFDM was used and in the uplink either CP-OFDM or DFT-OFDM could be used.
  
  Read more about . . . . Multiple access.
  
  
• Millimetre-Wave communications:   Millimetre wave mobile communications was not implemented for the initial deployments of the 5g mobile communications system as the technology for cost effective millimetre wave communications had not been sufficiently developed. The use of mmWave for 5G mobile communications will require a large number of base stations to give the required coverage.
  
  In preparation for the implementation of mmWave, frequencies are being allocated and fall within the FR2 (Frequency Range 2) set of allocations.
  
  Read more about . . . . mmWave mobile communications.
  
  
• Massive MIMO with beam-steering:   The antenna technologies for 5G have provided significant opportunities for enhancement of the performance over 4G. Although MIMO was used with 4G LTE, the technology has been taken further.
  
  Beam-steering technology has also been adopted to enable the transmitter and receiver antenna beams to be focussed towards the mobiles with which they are communicating. Each mobile can have its own beam, using advanced antenna technology, and this focussed the transmitted power where it is required and reduces interference between mobiles. This gives a significant improvement in performance.
  
  Read more about . . . . Massive MIMO & beam-steering.
  
  
• Dense networks:   Reducing the size of cells provides a much more overall effective use of the available spectrum. Whilst the large macro cells will be retained for general communications, many more small cells will be deployed to ensure that the data capacity can be provided.
  
  The use of smaller cells gives much greater frequency re-use and as a result the overall network can provide a significantly increased level of data capacity. As data usage is increasing rapidly, this is a clear and pressing requirement.

These are a few of the main techniques being developed and discuss for use within 5G.

5G timeline & dates

5G technology has developed rapidly. The first real deployments went live in 2019, and further deployments soon followed. Although there were some teething issues, many noticed a significant increase in speed.

New handsets were launched to accommodate the new technology and these enabled users to take advantage of much higher download speeds.

Many countries were keen to deploy 5G technology quickly as effective communications enable economic growth and are seen as an essential element of modern day life and industry.

5G mobile communications technology is rapidly developing and it is becoming the technology that everyone is moving towards. Not only will it be able to accommodate the super fast speeds required of it, but it will also be possible to accommodate the low data rate requirements for IoT and IIoT applications. As such 5G mobile communications will be able to encompass a huge number of different applications, and accommodate very many different data types.

  Written by Ian Poole .
  Experienced electronics engineer and author.

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