This brief examines current research on improving Vehicular Networks (VANETs), examining spectrum scarcity due to the dramatic growth of mobile data traffic and the limited bandwidth of dedicated vehicular communication bands and the use of opportunistic spectrum bands to mitigate congestion. It reviews existing literature on the use of opportunistic spectrum bands for VANETs, including licensed and unlicensed spectrum bands and a variety of related technologies, such as cognitive radio, WiFi and device-to-device communications. Focused on analyzing spectrum characteristics, designing efficient spectrum exploitation schemes, and evaluating the date delivery performance when utilizing different opportunistic spectrum bands, the results presented in this brief provide valuable insights on improving the design and deployment of future VANETs.
This book provides a comprehensive overview of wireless technologies for industrial network systems. The authors first describe the concept of industrial network systems and their application to industrial automation. They then go on to cover the role of sensing and control in industrial network systems, and the challenge of sensing and control in the industrial wireless environment. Then, the existing techniques for resource efficiency information transmission are introduced and studied. Afterward, the authors introduce sensing and control-oriented transmission for industrial network systems, which take advantage of spatial diversity gain to overcome the interference and fading, which in turn improves the transmission reliability without expending extra spectrum resources and enlarging the transmission delay. Subsequently, edge assisted efficient transmission schemes are introduced, which integrate the capacities of communication, computing, and control to relieve the contradiction ofresource limitation and massive data. Finally, the authors discuss open research issues and future works about information transmission in industrial network systems.
This book presents the modeling and transmission theory of RF OAM communications. The book features the UCA-based RF point-to-point OAM communication system, the UCA-based RF point-to-multipoint OAM wireless backhaul network, the HCCL structure for long-distance OAM transmissions, and the UCA-based joint OAM RadCom scheme. For the UCA-based RF point-to-point OAM communication system, a 2-D ESPRIT-based distance and AoA estimation method is first introduced, followed by an OAM reception scheme including the hybrid mechanical and electronic beam steering with the estimated AoA and the amplitude detection with the estimated distance. The proposed RF OAM communication scheme is extended to the RF OAM-MIMO system equipped with UCCAs. For the UCA-based RF point-to-multipoint OAM wireless backhaul network, an OAM-based multi-user distance and AoA estimation method is introduced, followed by a multi-user OAM preprocessing scheme. At last, the proposed methods are extended to the downlink multi-user OAM-MIMO wireless backhaul system equipped with UCCAs. Moreover, a novel HCCL structure is introduced to realize long-distance OAM transmission. For the UCA-based joint OAM RadCom scheme, an OAM-based 3-D super-resolution position estimation and rotation velocity detection method is introduced, and then the PCRB of the OAM-based estimates and the transmission rate of the integrated system are derived and analyzed. To achieve the best performance trade-off, the transmitted integrated OAM beams is optimized by means of an exhaustive search method. Finally, this book discusses future research directions to inspire further investigation in the field of RF OAM communications from different perspectives.
This book systematically and comprehensively studies on alternative media in Taiwan, using a historical approach and primary data and first hand collected materials to examine how political openness and social movement in the 1980s through the 1990s in Taiwan enabled the rapid growth and wide development of Taiwan's alternative media, what impact the alternative media in Taiwan had on its socio-political transformation, and what implications Taiwan's case of alternative media has for other societies, especially for other Asian societies.
This book would be a good reading for intellectuals, media professionals, government analysts, and the general public as well, who are interested in this topic.
