Integration and Provision for City Public Service in Smart City Cloud Union: Architecture and Analysis

City public service is recognized as a foundation to satisfy users' daily life in smart city. However, in the existing framework of smart city, different service providers are separated from each other and are incapable of providing communications with high reliability and low latency. On the other hand, data onto a smart city needs to be integrated, providing superb services for all of these users. As such, this article proposes the concept of "city cloud union" to embrace the whole city public service and raise the users' satisfaction. In the city cloud union, city public service can be divided into two main categories, individual service and subscription service. Then, a city public service relevance and sharing architecture of the city cloud union are constructed. In this architecture, knowledge mapping for information integration and cooperative sharing scheme are designed for performing individual service and accelerating the subscription service, respectively. Accordingly, for the quality of service in the city cloud union, an optimal distribution of genetic algorithm (ODGA) is proposed to complete the cache placement in the cooperative sharing scheme and obtain the ultra low latency. Simulation results illustrate that the proposed algorithm reveals the relationship between average latency and some key parameters in the smart city and it can reduce the latency effectively.