Recent technological advances in electronics, sensors, and communications have accelerated the widespread use of smart communication devices and high-speed networks. The communication technology is now used pretty much everywhere through a wide range of devices – from smartphones, tablets, laptops, and wearable computers to household electrical equipment such as game-stations, microwave ovens, and refrigerators, or even unmanned aerial vehicles (drones) and environmental monitoring devices. As a consequence, the networks that connect these communication devices have become more diverse. For instance, we have fixed optical fiber networks, wireless access networks, cellular networks, satellite networks, and vehicular networks. In addition, there are ad hoc networks, sensor networks, and so on. A key question arises from the diversification of these communication networks: are we efficiently utilizing these networks? Is it possible to further improve the abilities of such networks? My research interests focus not only on theoretical design of next generation networks and protocols in order to optimize the communication networks, but also stressing on practical scenarios.