Industry Specification Group (ISG) on Reconfigurable Intelligent Surfaces (RIS) Activity Report 2023

Chair: Arman Shojaeifard (InterDigital)

Reviewing and establishing global standardization for Reconfigurable Intelligent Surface technology.

RIS (Reconfigurable Intelligent Surface) describes a new type of system node that leverages smart radio surfaces – with thousands of small antennas or metamaterial elements – to dynamically shape and control radio signals in a goal-oriented manner.

RIS corresponds to a planar surface composed of a certain arrangement of unit-cells, whose properties can be dynamically controlled to change its response in the electromagnetic domain. RIS can be controlled dynamically and/or semi-statically through control signalling such to tune the incident wireless signals through reflection, refraction, focusing, collimation, modulation, absorption or any combination of these.

RIS can be potentially deployed for both indoor and outdoor usage, including offices, airports, shopping centres, lamp posts and advertising billboards, and may take any shape or be integrated onto objects. Its characteristics may also result in low energy consumption, making RIS a sustainable technology solution. RIS can be configured to operate at any part of the radio spectrum, including frequencies from below 6 GHz to THz, and may harness tools from Artificial Intelligence (AI) and Machine Learning (ML) to enable systems operation and optimization.

RIS technology will effectively turn the wireless environment into a service, inspiring a host of new use cases. These include enhancements to capacity, coverage, positioning, security, and sustainability, as well as the support of further sensing, wireless power transfer, and ambient backscattering capabilities.

Providing coverage continues to be a challenge for operators commercializing 5G, and existing deployment solutions such as IAB (Integrated Access and Backhaul) and NCR (Network-Controlled Repeater) may not be economically viable in all cases, e.g. indoors. Here RIS can serve as a new low-cost energy-efficient deployment solution for enhancing coverage and capacity performance in 5G‑Adv and future 6G networks, by intently reflecting signals to and from the end users. RIS may also be used to enable new types of wireless applications such as Integrated Sensing and Communications (ISAC).

ETSI’s Industry Specification Group on Reconfigurable Intelligent Surfaces (ISG RIS) gives ETSI members the opportunity to coordinate their pre-standardization research efforts on RIS technology across various EU/UK collaborative projects, together with global initiatives, paving the way for future standardization of the technology.

Since the launch of ISG RIS in September 2021, the group has been working on defining use cases and deployment scenarios, covering technological challenges, RIS channel models and evaluation frameworks, and clearly documenting the relevant requirements.

2023 was marked by the release of ISG RIS’ first phase of deliverables as a suite of three Group Reports (GRs).

Published in April, GR RIS-001 identifies and defines relevant RIS use cases, with corresponding general Key Performance Indicators (KPIs). It also describes deployment scenarios as well as potential requirements for each identified use case, to enable interoperability with existing and upcoming wireless technologies and networks. 11 concrete key use cases are identified in the report, where RIS deployment may provide enhancements or new functionalities.

Published in August, GR RIS 002 describes the technological challenges in deploying RIS as a new network node. Analyzing potential impacts to network architecture, protocol architecture and a RIS control framework, it offers recommendations for requirements and potential impact to specifications supporting RIS as a new feature.

Published in June, GR RIS 003 explores:

(i)  communication models that offer a trade-off between electromagnetic accuracy and simplicity for performance evaluation and optimization;

(ii)  channel models that include path-loss and multipath propagation effects, as well as the impact of interference; and

(iii)  KPIs and the methodology for evaluating the performance of RISs for application to wireless communications – including the coexistence between different network operators – and for comparing transmission techniques, communication protocols and network deployments.

Work meanwhile commenced during the year on three further Work Items – to be published as Group Reports:

  • RIS-004 on Implementation and Practical Considerations;
  • RIS-005 on Diversity and Multiplexing of RIS-aided Communications;
  • RIS-006 on Multi-functional Reconfigurable Intelligent Surfaces (RIS): Modelling, Optimisation, and Operation.

In June 2023, ISG RIS requested an extension of its period of activity for a further two years. After consultation with the ETSI BOARD the request was accepted by the ETSI Director-General. ISG RIS in its second phase will focus on informative and normative work including assessing the technology’s potential and providing technical requirements.

See the full list of ISG RIS Work Items currently in development here.