# Key Technologies for 6G-Enabled Smart Sustainable City
## 3 Standardization of Smart Sustainable City
### ICT Standardization for Smart Sustainable City  
The technical committee (TC) on smart cities, ISO/TC 268 [12], promotes standardization for smart cities, focusing on fostering sustainability within cities. Furthermore, ISO/IEC joint technical committee (JTC) 1 [13] has established working group (WG) 11 to investigate the standardization of ICT in smart cities. Within the ISO 37106 [14] standard, ISO/TC 268 has defined a smart operating model to implement a vision for a sustainable future. This model enables strategies and policies to operate more rapidly and reduce delivery risks. The new operation model focuses on citizen-centric and collaborative approaches, while the traditional city operation was inefficient and uncoordinated. In addition, this standard encompasses details of the delivery principles and risk management for the transition to a smart city operating model.  
ISO/IEC JTC 1 WG 11 focuses on standardizing the platform for evaluating performance metrics in smart city data processing, especially from the ICT perspective. ISO/IEC 30146 [15] describes a set of evaluation indicators related to the adoption and use of smart city ICT, providing detailed information on measurement methods. This facilitates understanding smart city performance from an ICT perspective and enables the assessment of the city's ICT readiness. Within the standard, smart city ICT indicators are categorized into performance indicators and capability indicators. Performance indicators encompass citizen service, efficient governance, and livable environment, while capability indicators include smart facilities, information resources, and cybersecurity.  
ITU-SG 20 [16] focuses on the standardization of key performance indicators (KPIs) to evaluate the use of ICT. Additionally, it focuses on standardizing IoT technologies for the establishment and operation of smart cities, aiming to address urban development challenges. ITU-T Y.4900/L.1600 [17] provides an overview of KPIs for SSC. These KPIs are categorized into six dimensions: (1) ICT, (2) environmental sustainability, (3) productivity, (4) quality of life, (5) equity and social inclusion, and (6) physical infrastructure, with each dimension comprising sub-dimensions. ITU-T Y.4901/L.1601 [18] covers how to evaluate the use of ICT and the utilization rate for each sub-dimension of the KPIs. Specifically, each sub-dimension incorporates the core indicator applicable to all cities, as well as the additional indicator that can be selected based on factors such as the city's economic strength, population, and geography. For example, Networks and access, a sub-dimension of the ICT dimension, includes the availability of wireless broadband subscriptions (core indicator) and the availability of WiFi in public areas (additional indicator) [18].  
ITU-T Y.4904 [19] introduces the SSC maturity model (SSC-MM) to identify the development or progress level of a specific city in terms of smart sustainable development. To measure the achievement of sustainable development goals (SDG), there are five maturity levels categorized into three dimensions: (1) economic, (2) environmental, and (3) social. The main topics for each dimension are shown in Table 2, and the maturity levels of the ICT infrastructure topic in the economic dimension are shown in Table 3.  
\begin{table}
\begin{tabular}{c c} \hline
**Country** & **Contents** \\ \hline \hline  & (2015) Smart city initiative: Establabl policies to solve various local problems and create new solutions for smart cities \\  & (2019) National spectrum Strategy: Plan to invest heavily in future technologies such as 5G, AI, advanced manufacturing, and quantum information science \\  & (2021) IoT strategy: Expand the approach by presenting an IoT framework based on the New York IoT strategy \\ \hline \hline \end{tabular}
\end{table}
Table 1: _Cont._