Multipath Transport Protocols for Video Streaming over Heterogeneous Wireless Networks

This dissertation presents a multipath transport protocol to provide a seamless high-quality video streaming service using multiple wireless networks simultaneously. Thanks to the fast development of communication and networking technologies, video streaming services are recently available anytime and anywhere. However, it is well known that the resources available over wireless networks are very limited compared to those over wired networks. In recent years, heterogeneous wireless networks have co-existed to support a variety of subscriber requirements. State of the art smart mobile devices have remarkable functionalities, such as high computing power, high-resolution display capability, and multiple advanced networking interfaces. Thus, users may expect that current mobile devices will improve the Quality-of-Service (QoS) by using multiple networking interfaces simultaneously. However, conventional transport protocols such as TCP and UDP cannot support multi-homing devices to use multiple paths concurrently. Therefore, a multipath transport protocol needs to be developed considering the functionalities of state of the art smart mobile devices for seamless video streaming. First, we present a multipath multimedia transport protocol (MPMTP), which exploits path diversity over heterogeneous wireless networks. The goal of MPMTP is to provide a seamless high-quality video streaming service by using multiple wireless networks simultaneously. In MPMTP, systematic Raptor codes are adopted to mitigate video quality degradation caused by wireless channel errors as well as to alleviate a head-of-line blocking problem in multipath environments, and their encoding parameters such as code rate, symbol size, and the number of source symbols are determined on the fly by considering the wireless channel state, Raptor encoding and decoding complexity, and receiver buffer occupancy. Furthermore, MPMTP performs packet scheduling considering not only wireless network conditions but also packet payload characteristics for smooth video playback. The proposed MPMTP is fully implemented in a Linux kernel and examined over real wireless network environments. Second, we propose an energy-aware multipath streaming transport protocol (EMSTP). The goal of the proposed EMSTP is to support a seamless high-quality video streaming service in an energy efficient way over heterogeneous wireless networks. One major concern of using multipath transport protocol in smart mobile devices is the higher energy required for maintaining multiple wireless networks. For an energy saving at the receiver side, EMSTP not only shapes a video stream into bursts, but also determines Raptor encoding parameters considering an energy consumption of Raptor decoding on the fly. The proposed EMSTP is fully implemented using C/C++ and Java at Android-based smartphone, and examined over heterogeneous wireless networks.