6G    

 

 

 

6G Radio Technologies

6G Radio will be targeted for covering many area that is not covered by the current technology or doing the similar thing as current technology in more advanced way. For those new features and implementation, 6G radio would incorporated many component technologies as described in this note.

Since nothing is clearly determined about specific radio technologies to be used for 6G implementation. I would just keep consolidating various ideas from different sources in this note.

Research Areas on 6G Radio Technlogy

Following illustration is based on the contents from Roadmap to 6G (Next G Alliance). This diagram presents a roadmap of cutting-edge innovations, from intelligent air interfaces to spectrum efficiency and eco-friendly systems, each playing a pivotal role in crafting a more connected and efficient world. These advancements promise to redefine wireless networking by leveraging artificial intelligence, enhancing device interconnectivity, and embracing green communication principles, marking a transformative leap in how we transmit information and perceive our environment

Followings are brief descriptions of each of these items.

  • AI and Distributed Cloud
    • the integration of AI and cloud computing distributed across the network infrastructure(from RAN through Core) to enhance processing capabilities and network intelligence.
  • Spectrum Expansion and Efficiency
    • THz/Sub-THz: Utilization of terahertz and sub-terahertz frequencies to provide higher data rates and bandwidth.
    • mmWave Enhancement: Improvements to millimeter-wave technology to facilitate better performance at higher frequencies.
    • Spectrum Sharing: Techniques that allow different systems to share the same spectrum more efficiently.
    • Advanced MIMO Technologies: Using multiple antennas at both the transmitter and receiver to improve communication performance.
    • Advanced Duplexing Schemes: Methods for separating the uplink and downlink communications to increase efficiency.
    • Waveform, Coding, Modulation, and Multiple Access: Innovations in signal processing that allow more data to be transmitted over the same frequency band.
  • Green Communication
    • Air Interface Enhancement for Distributed Computing and Intelligence across Device and Network: This suggests improvements in the way devices communicate wirelessly, with a focus on integrating distributed computing and artificial intelligence directly into the air interface—the part of the network that deals with the wireless communication aspects.
    • Focus on making network operations more environmentally friendly.
    • Zero-Energy Communications: Systems that aim to operate with minimal energy input.
    • Ultra-Low-Resolution Communications Systems: Communication systems that are efficient and require lower resolution or less complexity.
    • Device Power Saving: Technologies aimed at reducing the power consumption of devices.
  • Joint Communication and Sensing
    • Recognition of the surrounding environment: Technologies that enable devices to understand and interact with their environment.
    • Wireless sensing and positioning: The use of wireless signals for sensing purposes and for determining the position of devices.
  • Advanced Topology and Networking
    • Mesh Network: A network where devices are interconnected in a mesh topology to allow for efficient data routing.
    • Device to Device Communications: Enabling direct communication between devices without the need for a central access point.
    • Cooperative Communications: Techniques where devices work together to enhance communication performance.
    • Non-Terrestrial Communication: Communication solutions that involve non-earthly components such as satellites or airborne platforms.
    • Radio for extreme networking: Robust communication methods designed to work in extreme or challenging environments.

 

Following is a list of possible enablers suggested by Qualcomm : Why and what you need to know about 6G in 2022 .

The presentation deals with better ways to code channels for quick and efficient sending of information, and new waveforms that make the most of frequency and power. It also uses smarter methods to modulate and encode signals so we can do more with the airwaves we have. Plus, it introduces a fresh way of allowing lots and lots of devices to share the network without problems. All these pieces are key to a 6G network, which will make our internet faster, more stable, and save energy, ready for a world where everything is connected.

  • Channel Coding
    • Advanced channel coding aimed at achieving high throughput, low power usage, and cost-effective implementation. This coding strives to approach the theoretical limits of data transmission over various block lengths and signal-to-noise ratio (SNR) regimes.
  • Waveform
    • Introduction of new waveforms and advanced signal processing techniques to increase spectral and power efficiency across diverse spectrum bands in the 6G unified air interface (UAI).
  • Modulation
    • Enhanced modulation schemes designed to make more efficient use of the spectrum and available resources. These schemes enable higher data rates and are adaptable to various MIMO (Multiple Input Multiple Output) transmission systems.
  • Multiple Access
    • Ongoing development of scheduled multiple access methods in conjunction with advanced MIMO and duplexing technologies, which are critical for supporting very high cell capacity. It also includes the development of contention-based random access methods to scale up the massive number of devices in cellular systems efficiently.
  • Advanced RF and Baseband Joint Design:
    • Support for wider bandwidth, faster transmit/receive (Tx/Rx) switching, higher power amplifier (PA) efficiency, and massive spectrum aggregation across new and existing bands.
  • Efficient Modem System Implementation:
    • Modem-Radio Frequency (RF) implementations that are friendly to the physical layer (PHY), aiding in data rate scaling while maintaining superior power efficiency.
  • Advanced Air Interface Features:
    • Coevolution of waveform and multiple access with next-generation MIMO, flexible and full duplex technologies.
  • Extreme Energy-Efficient Devices:
    • Devices and use cases that vary widely, from those requiring extreme data rates to passive Internet of Things (IoT) applications.
  • Seamless Multi-RAT Connectivity and Spectrum Sharing:
    • Efficient multi-RAT (Radio Access Technology) for 5G/6G, allowing spectrum access and resource sharing over multiple users and connectivity across different RATs on the same device.
  • Enabling Immersive Experience:
    • Facilitating immersive experiences such as extended reality (XR) and metaverse by utilizing 6G air interface and new network topology technologies.

Main focus on TeraHz Communication

Key areas for developing end-to-end THzCom systems can be summarized in illustration as follows focusing on physical, link, and network layers. (NOTE : You see a specific name of the technology like Graphene, IRS etc, but we don't know yet which specific techology will be employeed in real 6G implementation. Take these specific name just as a candidate for future implementation).

Source : Terahertz Communications for 6G and Beyond Wireless Networks

Frequency Spectrum:

  • THzCom utilizes the terahertz frequency band, which is located between the microwave and infrared bands.
  • The THz band offers huge available bandwidths that can support data rates up to one terabit per second (Tb/s), which is 100 times that of 5G.
  • The entire THz band is divided into ultra-wideband transmission windows (TWs) and absorption coefficient peak regions (ACPRs).

Antenna Technology:

  • THzCom requires new antenna designs that can operate at higher frequencies and provide high gain and directivity.
  • Beamforming techniques are necessary to overcome the high path loss in the THz band.
  • NOTE : Just in terms of high level terminology (e.g, Beam Forming, Array Antenna etc) there wouldn't be much differences between 5G antenna technology and Thz antenna technology. But it is definitely more challenging to implment THz antenna. Refer to this note regarding some of the challenges with the implementation of Thz Antenna.

Other Enabling Technologies:

  • Other 6G-enabling technologies such as artificial intelligence (AI), machine learning (ML), and IRS(Intellegent Reflective Surface) can be integrated into THzCom to enhance its performance.
  • The integration of these technologies can help address challenges such as security, interference management, and energy efficiency.

Building Blocks of 6G Radio Hardware

The building blocks of 6G Radio (actually any kind of digital communication radio) can be summarized as follows (this is based on [1]).  Since these building blocks are mostly implemented by hardware electronics, you would find more detailed information from the note : 6G Electronics.

NOTE : In such a high frequency like sub Thz or Thz, the Antenna System may be integrated with Lenses or other reflective structures.

Reference

[1] Terahertz Band Communication: An Old Problem Revisited and Research Directions for the Next Decade

[2] Roadmap to 6G

[3] Terahertz Communications for 6G and Beyond Wireless Networks: Challenges, Key Advancements, and Opportunities (2022)

[4] Toward a 6G AI-Native Air Interface(2021)

[5] Overview of Prospects for Service-Aware Radio Access towards 6G Networks (2022)

[6] Why and what you need to know about 6G in 2022 - Qualcomm (2022)

[7] Terahertz Reconfigurable Intelligent Surfaces (RISs) for 6G Communication Links - 2022

[8] Deliverable D2.3 Radio models and enabling techniques towards ultra-high data rate links and capacity in 6G - Hera X

[9] The Generalization of Orthogonal Frequency Division Multiplexing With Subcarrier Power Modulation to Quadrature Signal Constellations