v FOREWORD The ITU-T Focus Group on Smart Sustainable Cities (FG-SSC) concluded its two-year study in May 2015 with the delivery of 21 Technical Reports and Specifications to provide the foundations of subsequent ITU-T standardization work. This compendium of the reports and specifications released by the Focus Group will assist the studies of all decision-makers with smart-city ambitions. Smart Sustainable Cities will contribute to the achievement of the Sustainable Development Goals by leveraging information and communication technologies (ICTs) to set cities on a development course characterized by environmental sustainability, resilience, and equitable social and economic growth. The ITU-T Focus Group on Smart Sustainable Cities encouraged collaboration among the many stakeholders expected to contribute to the development of Smart Sustainable Cities. The diverse group analyzed research on the topic of smart cities, addressing gaps in research and establishing a basis for the development of relevant international standards. Smart Sustainable Cities require trusted information infrastructure capable of supporting an enormous volume and diversity of ICT applications and citizen-driven services. The foundational ICT infrastructure of a smart city should ensure openness and interoperability, achieved with coordinated adherence to common standards.In June 2015, ITU members established the new ITU-T Study Group 20 to look at “Internet of Things and its applications including smart cities and communities”. ITU-T Study Group 20 is taking an innovative approach to IoT standardization by placing ITU’s technical expertise at the service of national and local governments, city planners and a wide range of vertical industries. We have also partnered with Dubai and Singapore in a two-year trial of ITU’s key performance indicators for Smart Sustainable cities, and we are in discussion with other cities interested in following suit. The development of Smart Sustainable Cities will require national and local governments to work in collaboration with industry and society to develop processes for more integrated decision-making. ITU-T Study Group 20 and the trial implementation of the key performance indicators are examples of new models of collaboration to improve the coordination of smart-city development. I trust that this compendium will provide a valuable reference point to the community driving the development of Smart Sustainable Cities. The Focus Group was successful in encouraging the collaboration of smart-city stakeholders, and this compendium is expected to play a similar role in building a common understanding of stakeholders’ respective responsibilities in the development of Smart Sustainable Cities. Chaesub Lee Director, ITU Telecommunication Standardization Bureau