5G (5th generation mobile networks or 5th generation wireless systems) denotes the next major phase of mobile telecommunications standards beyond the current 4G/IMT-Advanced standards. 5G is also referred to as beyond 2020 mobile communications technologies. 5G does not describe any particular specification in any official document published by any telecommunication standardization body.
Although updated standards that define capabilities beyond those defined in the current 4G standards are under consideration, those new capabilities are still being grouped under the current ITU-T 4G standards.
Background of 5G
A new mobile generation has appeared approximately every 10th year since the first 1G system, Nordic Mobile Telephone, was introduced in 1981. The first 2G system started to roll out in 1991, the first 3G system first appeared in 2001 and 4G systems fully compliant with IMT Advanced were standardized in 2012. The development of the 2G (GSM) and 3G (IMT-2000 and UMTS) standards took about 10 years from the official start of the R&D projects, and development of 4G systems started in 2001 or 2002. Predecessor technologies have occurred on the market a few years before the new mobile generation, for example the pre-3G system CdmaOne/IS95 in the US in 1995, and the pre-4G systems Mobile WiMAX in South-Korea 2006, and first release-LTE in Scandinavia 2009.
Mobile generations typically refer to non–backwards-compatible cellular standards following requirements stated by ITU-R, such as IMT-2000 for 3G and IMT-Advanced for 4G. In parallel with the development of the ITU-R mobile generations, IEEE and other standardisation bodies also develop wireless communication technologies, often for higher data rates and higher frequencies but shorter transmission ranges. The first gigabit IEEE standard was IEEE 802.11ac, commercially available since 2013, soon to be followed by the multi-gigabit standard WiGig or IEEE 802.11ad.
Based on the above observations, some sources suggest that a new generation of 5G standards may be introduced approximately in the early 2020s. However, still no international 5G development projects have officially been launched, and there is still a large extent of debate on what 5G is exactly about. Prior to 2012, some industry representatives have expressed skepticism towards 5G but later took a positive stand.
New mobile generations are typically assigned new frequency bands and wider spectral bandwidth per frequency channel (1G up to 30 kHz, 2G up to 200 kHz, 3G up to 20 MHz, and 4G up to 100 MHz), but skeptics argue that there is little room for larger channel bandwidths and new frequency bands suitable for land-mobile radio. From users' point of view, previous mobile generations have implied substantial increase in peak bitrate (i.e. physical layer net bitrates for short-distance communication), up to 1 Gbit/s to be offered by 4G.
If 5G appears, and reflects these prognoses, the major difference from a user point of view between 4G and 5G techniques must be something else than increased peak bit rate; for example higher number of simultaneously connected devices, higher system spectral efficiency (data volume per area unit), lower battery consumption, lower outage probability (better coverage), high bit rates in larger portions of the coverage area, lower latencies, higher number of supported devices, lower infrastructure deployment costs, higher versatility and scalability or higher reliability of communications. Those are the objectives in several of the research papers and projects below.
GSMHistory.com  has recorded three very distinct 5G network visions having emerged by 2014:
A super-efficient mobile network that delivers a better performing network for lower investment cost. It addresses the mobile network operators pressing need to see the unit cost of data transport falling at roughly the same rate as the volume of data demand is rising. It would be a leap forward in efficiency based on the IET Demand Attentive Network (DAN)philosophy 
A super-fast mobile network comprising the next generation of small cells densely clustered together to give a contiguous coverage over at least urban areas and gets the world to the final frontier for true “wide area mobility”. It would require access to spectrum under 4 GHz perhaps via the world's first global implementation of Dynamic Spectrum Access.
A converged fiber-wireless network that uses, for the first time for wireless Internet access, the millimeter wave bands (20 – 60 GHz) so as to allow very wide bandwidth radio channels able to support data access speeds of up to 10 Gb/s. The connection essentially comprises “short” wireless links on the end of local fiber optic cable.It would be more a “nomadic” service (like WiFi) rather than a wide area “mobile” service.
In 2008, the South Korean IT R&D program of "5G mobile communication systems based on beam-division multiple access and relays with group cooperation" was formed.
In 2012 the UK Government announced the setting up of a 5G Innovation Centre at the University of Surrey – the world’s first research centre set up specifically for 5G mobile research 
In 2012, NYU WIRELESS was established as a multi-disciplinary research center, with a focus on 5G wireless research as well as in the medical and computer science fields. The center is funded by the National Science Foundation and a board of 10 major wireless companies (as of July 2014) who serve on the Industrial Affiliates board of the center (www.nyuwireless.com). NYU WIRELESS has conducted and published some of the world's first channel measurements that show that millimeter wave frequencies will be viable for multi-Gigabit per second data rates for future 5G networks, and shares its extensive propagation database with the industrial affiliate sponsors of its research center. NYU WIRELESS hosted the first Brooklyn 5G Summit (B5GS) held on its Brooklyn, NY campus on April 24-25, 2014, where global leaders working on 5G provided thoughts and early results. The B5GS is an annual event that will be held in April, to bring together the research and technology leaders who are working on 5G.
In Europe, Neelie Kroes, the European Commissioner, committed in 2013 50 million euros for research to deliver 5G mobile technology by 2020. In particular, The METIS 2020 Project is driven by a car manufacturer and several telecommunicaitons companies, and aims at reaching world-wide consensus on the future global mobile and wireless communications system. The METIS overall technical goal is to provide a system concept that supports 1000 times higher mobile system spectral efficiency as compared with current LTE deployments. In addition, in 2013 another project has started, called 5GrEEn, linked to project METIS and focusing on the design of Green 5G Mobile networks. Here the goal is to develop guidelines for the definition of new generation network with particular care of energy efficiency, sustainability and affordability aspects.
Key concepts suggested in scientific papers discussing 5G and beyond 4G wireless communications are:
The IEEE Journal on Selected Areas in Communications published a special issue on 5G - see the issue for June 2014, containing, among other papers, a comprehensive survey of 5G enabling technologies and solutions. IEEE Spectrum has a story about millimeter wave wireless communications as a viable means to support 5G in its September 2014 issue.
Pearson/Prentice Hall has released the first comprehensive text on "Millimeter Wave Wireless Communications," authored by T. S. Rappaport, R. W Heath, Jr., Robert Daniels, and James Murdock. This text, over 700 pages in length, covers virtually all technical areas regarding potential 5G technologies, including all of the major global 60 GHz wireless local area network (WLAN) and personal local area network (WPAN) standards.
The world's first extensive radio propagation and channel models for millimeter wave wireless communications may be found in IEEE papers: "Millimeter Wave Mobile Communications for 5G Cellular: It Will Work!" in IEEE Access, Vol. 1, May 2013; "Broadband Millimeter-Wave Propagation Measurements and Models Using Adaptive-Beam Antennas for Outdoor Urban Cellular Communications, in IEEE Trans. Antennas and Propagation, April 2013, and many other peer-reviewed conference and journal papers by NYU WIRELESS students and faculty.
- Massive Dense Networks also known as Massive Distributed MIMO providing green flexible small cells 5G Green Dense Small Cells. A transmission point equipped with a very large number of antennas that simultaneously serve multiple users. With massive MIMO multiple messages for several terminals can be transmitted on the same time-frequency resource, maximising beamforming gain while minimising interference.
- Advanced interference and mobility management, achieved with the cooperation of different transmission points with overlapped coverage, and encompassing the option of a flexible usage of resources for uplink and downlink transmission in each cell, the option of direct device-to-device transmission and advanced interference cancellation techniques.
- Efficient support of machine-type devices to enable the Internet of Things with potentially higher numbers of connected devices, as well as novel applications such as mission critical control or traffic safety, requiring reduced latency and enhanced reliability.
- The usage of millimetre wave frequencies (e.g. up to 90 GHz) for wireless backhaul and/or access (IEEE rather than ITU generations)
- Pervasive networks providing Internet of things, wireless sensor networks and ubiquitous computing: The user can simultaneously be connected to several wireless access technologies and seamlessly move between them (See Media independent handover or vertical handover, IEEE 802.21, also expected to be provided by future 4G releases. See also multihoming.). These access technologies can be 2.5G, 3G, 4G, or 5G mobile networks, Wi-Fi, WPAN, or any other future access technology. In 5G, the concept may be further developed into multiple concurrent data transfer paths.
- Multi-hop networks: A major issue in beyond 4G systems is to make the high bit rates available in a larger portion of the cell, especially to users in an exposed position in between several base stations. In current research, this issue is addressed by cellular repeaters and macro-diversity techniques, also known as group cooperative relay, where also users could be potential cooperative nodes thanks to the use of direct device-to-device (D2D) communications.
- Cognitive radio technology, also known as smart-radio: allowing different radio technologies to share the same spectrum efficiently by adaptively finding unused spectrum and adapting the transmission scheme to the requirements of the technologies currently sharing the spectrum. This dynamic radio resource management is achieved in a distributed fashion, and relies on software-defined radio. See also the IEEE 802.22 standard for Wireless Regional Area Networks.
- Dynamic Adhoc Wireless Networks (DAWN), essentially identical to Mobile ad hoc network (MANET), Wireless mesh network (WMN) or wireless grids, combined with smart antennas, cooperative diversity and flexible modulation.
- Vandermonde-subspace frequency division multiplexing (VFDM): a modulation scheme to allow the co-existence of macro-cells and cognitive radio small-cells in a two-tiered LTE/4G network.
- IPv6, where a visiting care-of mobile IP address is assigned according to location and connected network.
- Wearable devices with AI capabilities. such as smartwatches and optical head-mounted displays for augmented reality
- One unified global standard.
- Real wireless world with no more limitation with access and zone issues.
- User centric (or cell phone developer initiated) network concept instead of operator-initiated (as in 1G) or system developer initiated (as in 2G, 3G and 4G) standards
- Li-Fi (a portmanteau of light and Wi-Fi) is a massive MIMO visible light communication network to advance 5G. Li-Fi uses light-emitting diodes to transmit data, rather than radio waves like Wi-Fi.
- World wide wireless web (WWWW), i.e. comprehensive wireless-based web applications that include full multimedia capability beyond 4G speeds.
- In 2008, the South Korean IT R&D program of "5G mobile communication systems based on beam-division multiple access and relays with group cooperation" was formed.
- On 8 October 2012, the UK's University of Surrey secured £35M for new 5G research centre, joint funded between the British government's UK Research Partnership Investment Fund (UKRPIF) and a consortium of key international mobile operators and infrastructure providers –including Huawei, Samsung, Telefonica Europe, Fujitsu Laboratories Europe, Rohde & Schwarz, and Aircom International– it will offer testing facilities to mobile operators keen to develop a mobile standard that uses less energy and radio spectrum whilst delivering faster than current 4G speeds, with aspirations for the new technology to be ready within a decade.
- On 1 November 2012, the EU project "Mobile and wireless communications Enablers for the Twenty-twenty Information Society" (METIS) starts its activity towards the definition of 5G. METIS intends to ensure an early global consensus on these systems. In this sense, METIS will play an important role of building consensus among other external major stakeholders prior to global standardisation activities. This will be done by initiating and addressing work in relevant global fora (e.g. ITU-R), as well as in national and regional regulatory bodies.
- In February 2013, ITU-R Working Party 5D (WP 5D) started two study items: (1) Study on IMT Vision for 2020 and beyond, and; (2) Study on future technology trends for terrestrial IMT systems. Both aiming at having a better understanding of future technical aspects of mobile communications towards the definition of the next generation mobile.
- On 12 May 2013, Samsung Electronics stated that they have developed the world's first "5G" system. The core technology has a maximum speed of tens of Gbit/s (gigabits per second). In testing, the transfer speeds for the “5G” network sent data at 1.056 Gbit/s to a distance of up to 2 kilometres.with the use of an 8*8 MIMO.
- In July 2013, India and Israel have agreed to work jointly on development of fifth generation (5G) telecom technologies.
- On 1 October 2013, NTT (Nippon Telegraph and Telephone), the same company to launch world first 5G network in Japan, wins Minister of Internal Affairs and Communications Award at CEATEC for 5G R&D efforts
- On 6 November 2013, Huawei announced plans to invest a minimum of $600 million into R&D for next generation 5G networks capable of speeds 100 times faster than modern LTE networks.
- On 8 May 2014, NTT DoCoMo start testing 5G mobile networks with Alcatel Lucent, Ericsson, Fujitsu, NEC, Nokia and Samsung.
- Head-mounted display (HMD)
- IEEE 802.11u authentication
- IEEE P1905 hybrid networking
- Ka band
- OpenFlow/OpenRadio for sharing backhaul.
- Ultra-wideband (UWB)
- Virtual retinal display
- Web 2.0
- Web 3.0
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4th Generation (4G)
|Mobile Telephony Generations||Succeeded by
6th Generation (6G) (a future standard)