As the world eagerly anticipates the arrival of applicable 6G innovations, researchers face numerous challenges in validating this next-generation wireless communication technology. The journey from theoretical concepts and mathematical equations to real-world 6G implementation is complex and requires meticulous planning, testing, and measurements to better characterize these ultra-high frequencies.
Not only must 6G research help uncover specific channel behaviors ─ it also validates how these new frequencies, waveforms, and other capabilities will perform from the physical layer up to the higher-layer protocols. Let’s dive into the challenges that researchers must resolve:
Channel-Level 6G Challenges
- High-frequency signal propagation:
- Path loss: Sub-terahertz and terahertz (THz) bands are prone to significant signal attenuation, losing signal strength over long distances. They also encounter penetration loss where high-frequency signals fade upon encountering obstacles like buildings and foliage, leading to coverage issues.
- Atmospheric absorption: THz signals are particularly susceptible to absorption by atmospheric gases, reducing signal strength and reliability.
- Link budget challenges: The broad bandwidth of 6G signals can lead to low signal-to-noise ratios, as energy is spread over a wider frequency range.
- Multipath propagation:
- Interference: Signals reflecting off surfaces and arriving at the receiver at different times cause interference and signal distortion. This is exacerbated in urban environments.
- Fading: Rapid fluctuations in signal amplitude due to multipath effects lead to inconsistent signal quality and reduced communication reliability.
- Beamforming and beam management:
- Beam alignment: Precise beamforming techniques are required to direct high-frequency narrow beams towards the receiver, which is challenging in dynamic environments.
- Beam tracking: Continuous tracking of the receiver’s location to adjust the beam direction in real time adds complexity to the system.
Network-Level 6G Challenges
- Network density and interference:
- Inter-cell interference: Dense networks with numerous small cells may increase inter-cell interference, degrading overall network performance.
- Spectrum management: Efficient spectrum management is crucial to minimize interference and maximize the use of available frequencies.
- Latency and reliability:
- Ultra-low latency: Achieving ultra-low latency targets (e.g., one-microsecond latency) requires highly efficient signal processing and transmission techniques.
- Reliability: Ensuring reliable communication in diverse environments, including urban, rural, and remote areas, is a significant challenge.
- Integration with heterogeneous networks:
- Seamless handover: Integrating 6G networks with existing 5G and other wireless technologies requires seamless handover between various network types.
- Interoperability: Ensuring interoperability between various network components and technologies, such as satellite, terrestrial, and aerial networks, is critical for achieving comprehensive coverage and performance goals.
From 6G Theory to Simulation, and Emulation
6G researchers are modeling systems, channel propagation, and waveforms with design simulation software tools.
The next step in this 6G development process is to take these simulations into real-world signal emulation. Emulation is crucial for testing the performance of 6G systems in real-time channels and networks, from the physical layer to higher layer protocols.
Emulating 6G signals in a controlled lab environment enables researchers to accurately assess the performance of 6G systems. This includes evaluating the challenges mentioned earlier under repeatable conditions to fine-tune program iterations against varying scenarios. Researchers can also study system vulnerabilities by emulating cybersecurity issues and addressing them early on.
6G: From Innovative Research to Reality
The industry expects 6G commercialization to happen by 2030 – leaving at best five years to bring to fruition both products and applications which must meet conformance standards that are still in various stages of formulation. Researchers, device and component designers, test and measurement specialists, network and cybersecurity engineers, and regulatory authorities are collaborating across the 6G ecosystem to bring 6G to life.
Recently, Keysight had the opportunity to visit the 6G research labs at Northeastern University, where the researchers shared their exciting projects. These covered:
- Studying a 130 GHz broadband MIMO system to increase data throughput and transmission distance. The MIMO system uses two data streams with 10 GHz of bandwidth at 130 GHz to achieve a 36 Gbps over-the-air transmission.
- Emulating a person-in-the-middle attack scenario to eavesdrop on a highly directional sub-THz communication link. The person-in-the-middle attack scenario uses a metasurface to bend a highly directional sub-THz beam towards an eavesdropper receiver while maintaining the line-of-sight link.
- Researching real-time sub-THz for network applications. The real-time sub-THz test bed uses an FPGA prototyping system with high-speed digital-to-analog converters (DACs) and analog-to-digital converters (ADCs), capable of supporting 8-10 GHz of contiguous bandwidth at sub-THz frequencies to get up to 60 Gbps.
Keysight’s production crew captured highlights of these exciting 6G projects, so that we can share them with you in this online event: Innovating for 6G with Keysight & Northeastern University. Pick a date and time that is convenient for you to attend.
