Dynamic media streaming with predictable reliability and opportunistic TCP-friendliness

Due to the increasing number of portable and mobile consumer electronics devices, today´s Internet paths include generally at least one wireless segment. Predominant architectures are IEEE 802.11 wireless as well as 3G/4G mobile networks. Dynamic stream switching schemes such as DASH (Dynamic Adaptive Streaming over HTTP) have been developed in order to adapt the rigid bandwidth requirement of real-time video services to the dynamic capacity of such Internet channels. Meanwhile, the actual bandwidth provisioning on wireless and mobile networks is no longer the limiting factor for high definition media streaming. However, the quality of such HTTP/TCP-based stream switching services is severely affected by the inefficiency of TCP´s loss-based congestion control, the ACK-clocked window control as well as the ARQ-only error control in presence of physical packet loss and large propagation delay. In this paper we address this quality bottleneck on wireless and mobile networks via a novel dynamic streaming architecture that proactively transmits packetized multimedia services under delay-based congestion control. The presented scheme builds upon the Predictably Reliable Real-time Transport protocol (PRRT) that efficiently provides the reliability required by multimedia services under their specific delay constraint. Under the delay-based congestion control the transport protocol implements opportunistic TCP-friendliness, which allows media streams to acquire additional bandwidth that remains unutilized by inefficient TCP sessions. We evaluate the bandwidth allocation of our dynamic streaming approach and demonstrate a significant increase of the video bit rate compared to HTTP-DASH on mobile broadband and wireless home network infrastructures as well as an emulated broadband access network path.