The state of the art in propagation and mobile channel modeling [From the Guest Editors]

In recent years, the ever-increasing demand for multimedia services, high mobility, and global connectivity has resulted in an explosion of new technologies for wireless communication systems. The design of all components of wireless communication systems, ranging from digital modulation schemes over channel coding techniques up to higher-layer protocols, is influenced by the propagation characteristics of the mobile channel. A thorough understanding of mobile channels is, therefore, crucial for the development, performance optimization, and testing of present as well as next-generation mobile communication systems. This is the reason why exploring the mobile channel has been a key research topic since the beginning of mobile communications. Currently, the research on propagation and mobile channel modeling involves a variety of challenging topics, such as the modeling of vehicle-to-vehicle channels; high-speed railway channels; power-line communication channels; multiple-input, multiple output (MIMO) channels; air-to-ground channels for future unmanned aircraft systems; and indoor-to-outdoor channels, to name only a few. The objective of this special issue is to capture the state of the art in the fascinating areas of propagation and mobile channel modeling.