5G Mobile Wireless Technology
- preliminary details and information about the wireless technology being developed for 5th generation or 5G mobile wireless or cellular telecommunications systems
With the 4G telecommunications systems now starting to be deployed, eyes are looking towards the development of 5th generation or 5G technology and services.
Although the deployment of any wireless or cellular system takes many years, development of the 5G technology systems is being investigated. The new 5G technologies will need to be chosen developed and perfected to enable timely and reliable deployment.
The new 5th generation, 5G technology for cellular systems will probably start to come to fruition around 2020 with deployment following on afterwards.
5G mobile systems status
The current status of the 5G technology for cellular systems is very much in the early development stages. Very many companies are looking into the technologies that could be used to become part of the system. In addition to this a number of universities have set up 5G research units focussed on developing the technologies for 5G
In addition to this the standards bodies, particularly 3GPP are aware of the development but are not actively planning the 5G systems yet.
Many of the technologies to be used for 5G will start to appear in the systems used for 4G and then as the new 5G cellular system starts to formulate in a more concrete manner, they will be incorporated into the new 5G cellular system.
The major issue with 5G technology is that there is such an enormously wide variation in the requirements: superfast downloads to small data requirements for IoT than any one system will not be able to meet these needs. Accordingly a layer approach is likely to be adopted. As one commentator stated: 5G is not just a mobile technology. It is ubiquitous access to high & low data rate services.
5G cellular systems overview
As the different generations of cellular telecommunications have evolved, each one has brought its own improvements. The same will be 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.
Any new 5th generation, 5G cellular technology needs to provide significant gains over previous systems to provide an adequate business case for mobile operators to invest in any new system.
Facilities that might be seen with 5G technology include far better levels of connectivity and coverage. The term World Wide Wireless Web, or WWWW is being coined for this.
For 5G technology to be able to achieve this, new methods of connecting will be required as one of the main drawbacks with previous generations is lack of coverage, dropped calls and low performance at cell edges. 5G technology will need to address this.
Although the standards bodies have not yet defined the parameters needed to meet a 5G performance level yet, other organisations have set their own aims, that may eventually influence the final specifications.
Typical parameters for a 5G standard may include:
|Suggested 5G Wireless Performance|
|Network capacity||10 000 times capacity of current network|
|Peak data rate||10 Gbps|
|Cell edge data rate||100 Mbps|
|Latency||< 1 ms|
These are some of the ideas being put forwards for a 5G standard, but they are not accepted by any official bodies yet.
There are several key areas that are being investigated by research organisations. These include:
- Millimetre-Wave technologies: Using frequencies much higher in the frequency spectrum opens up more spectrum and also provides the possibility of having much wide channel bandwidth - possibly 1 - 2 GHz. However this poses new challenges for handset development where maximum frequencies of around 2 GHz and bandwidths of 10 - 20 MHz are currently in use. For 5G, frequencies of above 50GHz are being considered and this will present some real challenges in terms of the circuit design, the technology, and also the way the system is used as these frequencies do not travel as far and are absorbed almost completely by obstacles. Read more about 5G millimetre wave links
- Future PHY / MAC: The new physical layer and MAC presents many new interesting possibilities in a number of areas:
- Waveforms: One key area of interest is that of the new waveforms that may be seen. OFDM has been used very successfully in 4G LTE as well as a number of other high data rate systems, but it does have some limitations in some circumstances. Formats being proposed include: GFDM, Generalised Frequency Division Multiplexing, as well as FBMC, Filter Bank Multi-Carrier, UFMC, Universal Filtered MultiCarrier. Each has its own advantages and limitations and it is possible that adaptive schemes may be employed, utilising different waveforms adaptively for the 5G mobile systems as the requirements dictate. This provides considerably more flexibility for 5G mobile communications. Read more about 5G waveforms
- Multiple Access Schemes: Again a variety of new access schemes are being investigated for 5G technology. Techniques including OFDMA, SCMA, NOMA, PDMA, MUSA and IDMA have all been mentioned. Read more about 5G multiple access schemes
- Modulation: Whilst PSK and QAM have provided excellent performance in terms of spectral efficiency, resilience and capacity, the major drawback is that of a high peak to average power ratio. Modulation schemes like APSK could provide advantages in some circumstances. Read more about 5G modulation schemes
- Duplex methods: There are several candidate forms of duplex that are being considered. Currently systems use either frequency division duplex, FDD or time division duplex, TDD. New possibilities are opening up for 5G including flexible duplex, where the time or frequencies allocated are variable according toth e load in either direction or a new scheme called division free duplex or single channel full duplex. This scheme for 5G would enable simultaneous transmission and reception on the same channel. Read more about 5G full duplex
- Massive MIMO: Although MIMO is being used in many applications from LTE to Wi-Fi, etc, the numbers of antennas is fairly limited -. Using microwave frequencies opens up the possibility of using many tens of antennas on a single equipment becomes a real possibility because of the antenna sizes and spacings in terms of a wavelength.
- Dense networks Reducing the size of cells provides a much more overall effective use of the available spectrum. Techniques to ensure that small cells in the macro-network and deployed as femtocells can operate satisfactorily are required.
Other 5G concepts
There are many new concepts that are being investigated and developed for the new 5th generation mobile system. Some of these include:
- Pervasive networks : This technology being considered for 5G cellular systems is where a user can concurrently be connected to several wireless access technologies and seamlessly move between them.
- Group cooperative relay: This is a technique that is being considered to make the high data rates available over a wider area of the cell. Currently data rates fall towards the cell edge where interference levels are higher and signal levels lower.
- Cognitive radio technology: If cognitive radio technology was used for 5th generation, 5G cellular systems, then it would enable the user equipment / handset to look at the radio landscape in which it is located and choose the optimum radio access network, modulation scheme and other parameters to configure itself to gain the best connection and optimum performance.
- Wireless mesh networking and dynamic ad-hoc networking: With the variety of different access schemes it will be possible to link to others nearby to provide ad-hoc wireless networks for much speedier data flows.
- Smart antennas: Another major element of any 5G cellular system will be that of smart antennas. Using these it will be possible to alter the beam direction to enable more direct communications and limit interference and increase overall cell capacity.
There are many new techniques and technologies that will be used in the new 5G cellular or mobile telecommunications system. These new 5G technologies are still being developed and the overall standards have not yet be defined. However as the required technologies develop, they will be incorporated into the new system which will be defined by the standards bodies over the coming years.
By Ian Poole
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