Tackling network congestion with ISAC and RIS
Network congestion is a constant challenge in wireless communications from 1G to the forthcoming 6G. As the number of connected devices skyrockets, the limited available bandwidth must be allocated judiciously to allow for higher network capacity and speed.
Recently, two advancements have emerged with the most promising ways to address this challenge: Integrated Sensing and Communication (ISAC) and Reconfigurable Intelligent Surfaces (RIS). Individually or combined, ISAC and RIS can enhance capacity, reduce congestion, and provide improved user experiences.
Understanding ISAC and RIS
ISAC provides the network operator with more intelligence about users. ISAC enables the efficient reuse of resources, including hardware and waveforms, to combine the sensing and communication functions. The same equipment that offers communication services can also sense the environment, providing valuable data about user locations and movements. Access to this data enhances the user experience by allowing the network to communicate optimally with users.
RIS, on the other hand, addresses the problem of signal blockage and low signal power, especially in high-density urban settings. RIS allows RF signals’ reflections to be reconfigured based on the location of the user. Once the user’s location is determined, RIS manipulates signals’ phase, amplitude and polarisation to direct them toward specific users. This capability ensures signals reach their intended audience, even in environments with obstacles, such as dense foliage, tall buildings in urban areas, or indoor settings with multiple walls and partitions.
The synergy of ISAC and RIS
The real power of ISAC and RIS lies in their synergy. ISAC’s sensing capabilities can inform RIS on how to best direct signals. RIS uses the data ISAC provides to minimise interference and ensure each user receives the strongest possible connection. Adjusting signal paths in real time helps alleviate network congestion and optimise available bandwidth by steering signals around obstacles and directing them toward users.
One key advantage of coupling ISAC and RIS is their economic viability. These technologies do not require new base stations and minimal new hardware and investment. Instead, engineers can integrate them into existing network set-ups and avoid major infrastructure changes. ISAC uses existing base station set-ups, simply enhancing their operation with sensing capabilities. While RIS requires some investment in metasurfaces, the overall hardware investment is significantly lower than deploying new base stations or overhauling existing network infrastructure.
Potential use cases for ISAC and RIS
The combination of ISAC and RIS is promising for addressing network congestion and enhancing connectivity in a variety of applications, including broadband wireless communications, autonomous vehicles and smart manufacturing.
Broadband wireless communications
In urban environments where obstacles cause signal deterioration, ISAC and RIS overcome these challenges to enable robust, high-speed internet access. ISAC gathers intelligence about user locations and movements to optimise signal delivery. RIS uses building surfaces with reconfigurable elements that alter signals to overcome blockages and enhance connectivity based on the user locations ISAC provides.
Autonomous vehicles
In autonomous vehicle operation, ISAC offers customised communication services that enable precise and reliable communication for real-time decision-making. RIS allows engineers to manipulate the environment, ensuring the signal is focused only where needed. Using ISAC and RIS in autonomous vehicle communication supports safe and efficient operations by reducing accidents and improving traffic flow.
Smart manufacturing
Smart manufacturing relies on efficient communication and sensing to optimise production processes and improve operational efficiency. ISAC and RIS technologies facilitate these goals by enabling real-time data exchange and environmental monitoring within manufacturing facilities. ISAC’s sensing capabilities provide detailed insights into machine operations and environmental conditions, while RIS ensures reliable connectivity by dynamically adjusting signal paths to avoid interference. This combination enhances the flexibility and responsiveness of manufacturing systems, allowing for more efficient resource utilisation and reduced downtime, even in highly congested industrial environments.
Best practices in ISAC and RIS deployment
Engineers should employ various best practices, including environmental modelling, custom waveform development, and advanced algorithm and hardware implementation, to effectively deploy ISAC and RIS into modern communication systems.
Precise modelling and simulation of the propagation environment are crucial for successful ISAC deployment. Any errors during modelling propagate and affect the final design. Path loss, multipath and signal reflection must all be accurately modelled to optimise performance and system efficiency. Additionally, it’s essential to use ray tracing to model the wireless channel by simulating the reflection, refraction and diffraction of electromagnetic waves in the environment. Ray tracing requires extreme precision as it is susceptible to atmospheric effects. Modelling and simulation are vital because the accuracy of the propagation environment directly affects waveform effectiveness.
Wireless communication waveforms based on industry standards cannot be used in ISAC and RIS design. Instead, engineers must design custom waveforms to enable sensing and communication to work together seamlessly. Engineers can use the Wireless Waveform Generator app in MATLAB to generate standards-based waveforms. Carefully designed waveforms enable ISAC and RIS to achieve high-resolution sensing and maintain robust communication links. When it comes time to deploy ISAC and RIS systems, their success hinges on both the waveform design and the sophisticated algorithms and hardware solutions that manage the complex computations needed for accurate sensing and communication.
Deploying ISAC and RIS technologies requires developing efficient algorithms and advanced hardware solutions to ensure reliable real-time performance. Engineers must implement the algorithms primarily on field-programmable gate arrays (FPGAs) because of their high-speed processing capabilities, but this puts a burden on the real-time performance of the FPGAs. Therefore, the algorithms implementing ISAC and RIS must be optimised using FPGA-ready IP blocks.
ISAC and RIS in 6G and beyond
As the era of 6G wireless communications draws closer, the challenge that network congestion presents grows with every passing day. The integration of ISAC and RIS has the potential to transform many industries by enabling simultaneous sensing and communication and optimising signal propagation and coverage. Their economic viability makes them even more attractive as they offer cost-effective solutions that take advantage of existing infrastructure without extensive overhauls. As engineers push the boundaries of 6G wireless communications and beyond, the synergy of ISAC and RIS will play a central role in shaping tomorrow's wireless networks.
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