# Reviews Based on the Reconfigurable Intelligent Surface Technical Issues
## 2 Technical Considerations for RIS  
### RIS Standardization  
Some of the pain points for the industry, especially network operators, in current 5G networks are scarce spectrum, high power consumption, and high deployment and maintenance costs. The overall goal of 3 GPP and several other Standards Development Organizations (SDOs) is to support new paradigms and capabilities that can meet the needs of 5G networks and beyond by using limited spectrum, power, and hardware costs [22]. The RIS has recently emerged as a promising technology for next-generation wireless networks such as B5G and 6G, and there is a broad consensus in academia and industry that the RIS, which uses modulation and coding techniques to artificially configure the channel for optimized performance, can revolutionize the current communication paradigm of adapting to the channel [23]. The standardization process typically starts with Study Items (SIs) in one or several SDOs or industry forums, and then expands to international SDOs such as 3 GPP, where Work Items (WIs) are established, technical specifications are comprehensively defined, and then are published and finalized as global standards. RIS-related SDO activities are centered in the United States, Europe, and China. In the U.S., two Special Interest Groups (SIGs) and one Emerging Technology Initiative (ETI) [24] have been established within the IEEE Communication Society, Reconfigurable Intelligent Surfaces for Smart Radio Environment (RISE) [25] and REconFigurable Intelligent Surfaces for Signal Processing and CommunicatONS (REFLECTIONS) [26], to foster collaboration among researchers in various fields such as wireless communications, signal processing, and metamaterials. In addition, industries, such as carriers and network infrastructure providers, are being engaged to provide understanding from an industrial perspective and to discuss the costs and potential applications of RISs. In Europe, the European Telecommunications Standards Institute (ETSI) proposed and approved an Industry Specification Group (ISG) on the RIS in June 2021, with participation from chipset vendors, network infrastructure providers, telecommunication companies, research organizations, and universities. The ISG defined the use of the RIS, developed key performance indicators (KPIs), published deliverables such as technical reports on RIS deployment scenarios, communication models, and channel models, and proposed 11 core use cases of RISs in May 2023 [27; 28]. Figure 9 shows ETSI's plans for RIS standardization by year [28]. Figure 9: RIS standardization of ETSI. In China, two standards organizations, China Communications Standards Association (CCSA) and FuTURE Forum, which is a non-profitable international organization jointly initiated by famous mobile telecommunication operators, mobile communication device manufactures, research institutes, and universities from both home and abroad in 2005, have started RIS-related standardization work. CCSA is an official standards organization established by enterprises and institutions in China to conduct standardization activities in the ICT field, and a proposal to create an SI for RISs was approved at the 55 th meeting of TC5-WG6 in 2020 [29]. CCSA conducts research on realizing RIS-enabled wireless communication systems, including channel modeling, channel estimation and feedback, beamforming using RIS, RIS, and AI, and networking protocols for RIS-enabled networks, while FuTURE Forum conducts research on integrating RIS into next-generation wireless communication [30]. In addition to these regional RIS standardization activities, as a global standardization, during the ITU-R Working Party (WP) 5D meeting in October 2020, each country submitted candidate proposals for next-generation wireless technologies to be included in the IMT Future Technology Trends Report, and a report including an RIS was submitted, led by Chinese companies.