The Vision and Requirements of the 6G Systems

- The Vision of the 6G Systems

6G will be like 5G, but more so. Even higher speeds, even lower latency, and masses of bandwidth. Researchers and scientists are talking about 6G going beyond a “wired” network, with devices acting as antennas using a decentralized network not under the control of a single network operator. If everything connects using 5G, 6G will set these connected devices free, as higher data speeds and lower latency make instant device-to-device connection possible.

The researchers around the globe are proposing cutting edge technologies such as artificial intelligence (AI)/machine learning (ML), quantum communication/quantum machine learning (QML), blockchain, tera-Hertz and millimeter waves communication, tactile Internet, non-orthogonal multiple access (NOMA), small cells communication, fog/edge computing, etc., as the key technologies in the realization of beyond 5G and 6G communications. I

The vision of future 6G wireless system, network architecture, and its emerging technologies such as artificial intelligence (AI), terahertz communications, optical wireless technology, free space optic network, blockchain, three dimensional networking, quantum communications, unmanned aerial vehicle, cell-free communications, integration of wireless information and energy transfer, integration of sensing and communication, integration of access-backhaul networks, dynamic network slicing, holographic beamforming, and big data analytics that can assist the 6G architecture development in guaranteeing the QoS. 

- The Requirements of the 6G Systems

The 6G systems aim to achieve high spectral and energy efficiency, low latency, and massive connectivity because of extensive growth in the number of Internet-of-Things (IoT) devices. These IoT devices will realize advanced services such as smart traffic, environment monitoring, and control, virtual reality (VR)/virtual navigation, telemedicine, digital sensing, high definition (HD), and full HD video transmission in connected drones and robots. 

IoT devices are predicted to reach 25 billion by the year 2025, and therefore, it is very challenging for the existing multiple access techniques to accommodate such a massive number of devices. Even 5G systems, which are being rolled out in the world at the moment, cannot support such a high number of IoT devices. Third generation partnership project (3GPP) is already working on the development of 5G standard and has identified massive machine type communication (mMTC), ultra-reliable and low latency communication (URLLC), and enhanced mobile broad band (eMBB) as three main use cases for 5G in its Release 13 (R13). 

At the same time, algorithms for the next generation (6G) communication systems, which will have the performance higher than that of existing 5G networks, are being developed. A typical 5G communication system has the capability to support at most 50,000 IoTs and/or narrowband IoT (NB-IoT) devices per cell. Specifically, a more robust network must be designed to realize the massive access in beyond 5G (B5G)/6G communication systems. 

Currently, there is little information about the standards of 6G. However, it is estimated that the international standardization bodies will sort out the standards for 6G by the year 2030. The work at some of the research centers has shown that 6G will be capable of transmitting a signal at a human computational capability by the year 2035. While the rollout of 5G is still underway, the researchers across the world have started working to bring a new generation of wireless networks.

- 6G vs. 5G

The most obvious difference is speed. 6G will use more advanced radio equipment and greater capacity and diversity of airwaves than 5G, including the use of extremely high frequency (EHF) spectrum, to deliver ultra-high speeds and massive capacity over short distances. 

4G speeds are discussed in megabits, while 5G will break the gigabit barrier and 6G will deliver theoretical terabit speeds. Most users will get over 100Gbps, but this is still a transformative bitrate.

In terms of coverage, 6G may become ubiquitous. 6G satellite technology and smart surfaces that reflect electromagnetic signals will provide low-latency, multi-gigabit connectivity in parts of the world where traditional mobile networks are difficult or too expensive. Remote areas of the planet, the sky and the oceans can all be connected.

While 5G already leverages artificial intelligence for optimization, dynamic resource allocation and data processing, ultra-low latency of less than one millisecond and decentralized architecture means 6G will be able to deliver integrated intelligence everywhere. In fact, Japanese operator NTT DoCoMo believes that 6G will achieve artificial intelligence similar to the human brain. 

6G will also be more efficient and consume less power than its predecessor. Due to the expected growth in data generation, energy efficiency is critical for a more sustainable mobile industry.

- AI-Enabled 6G Air Interface

AI-enabled 6G air interface (or AI-AI) is a key component of 6G networking that uses artificial intelligence (AI) and machine learning (ML) to replace parts of the signal processing chain on the physical layer. The goal of AI-AI is to serve applications with the data they need in the most efficient way possible, while taking into account the available hardware and radio environment.

 AI-AI could give radios the ability to:

• Learn from their environments and each other
• Adapt their signaling schemes to perform best in any situation
• Make smart choices, such as reconfiguring signal paths, modulation schemes, and moving between spectrum bands
• Set up bespoke constellations, waveforms, and pilot signals

Some other potential benefits of AI-AI include: Improved performance, Increased energy efficiency, Simplified network management and optimization, and Cheaper network operation.

To establish an AI-native air interface, individual processing blocks are replaced with trained ML models, and then tasks that logically belong together are combined into a single model.

For example, channel equalization, channel estimation, and demapping tasks could be combined into a single trained ML model called a neural receiver.
 

- The 6G Ecosystem

In the 6G era, the digital, physical and human world will seamlessly fuse to trigger extrasensory experiences. Intelligent knowledge systems will be combined with robust computation capabilities to make humans endlessly more efficient and redefine how we live, work and take care of the planet. 

The 6G ecosystem is a collaborative network of researchers, businesses, and ICT enterprises. It's expected to support technologies like: 

• Automated cars
• Smart-home networks
• E-health
• Precision health care
• Smart agriculture
• Earth monitor
• Digital twins
• Cobots
• Robot navigation

6G will also include features like:

• Intelligent connected management and control functions
• Programmability
• Integrated sensing and communication
• Reduction of energy footprint
• Trustworthy infrastructure
• Scalability
• Affordability

The FCC estimates that 6G's frequencies will be between 95 GHz to 3 THz, which is 3 to 1,000 times more potent than 5G's frequencies. However, the frequencies are non-ionizing and safe.