CodePlay: Live multimedia streaming in VANETs using symbol-level network coding

The fundamental challenges of providing live multimedia streaming (LMS) services in vehicular ad hoc networks (VANETs) come from achieving stable and high streaming rate (smooth playback) for all the interested vehicles while using minimal bandwidth resources, especially under the highly dynamic topology of VANETs and the lossy nature of vehicular wireless communications. Packet level network coding (PLNC) technique has been widely accepted as an effective approach to improve the network performance during the last decade. More recent symbol-level network coding (SLNC) could further improve the efficiency of bandwidth utilization by exploiting both wireless symbol-level diversity and the benefits of network coding. In this paper, we introduce CodePlay, a new LMS scheme in VANETs that fully takes advantage of SLNC through a coordinated local push mechanism. Streaming contents are actively disseminated from dedicated sources to interested vehicles via local coordination of distributively selected relays, each of which will ensure smooth playback for vehicles nearby. Extensive simulations show that simply replacing the SLNC with PLNC technique in previous LMS schemes can not provide satisfiable user experience, and special scheme design based on the unique characteristics of SLNC proposed in CodePlay is necessary for future LMS applications in VANET.